Low-density lipoprotein is the major carrier of lipid hydroperoxides in plasma. Relevance to determination of total plasma lipid hydroperoxide concentrations

Comparative Susceptibility to Oxidation of Different Classes of Blood Plasma Lipoproteins

The kinetics of free radical peroxidation of different classes of blood plasma lipoproteins (nanoparticles involved in lipid transport in the body) was studied. The susceptibility of atherogenic low-density lipoproteins (LDLs) to the Cu2+-initiated free radical peroxidation in vitro was found to be more than ten times higher than that of antiatherogenic high density lipoproteins (HDLs). The baseline content of acyl hydroperoxy derivatives of phospholipids (primary products of free radical peroxidation) in the outer layer of LDL particles in vivo measured per particle exceeded the baseline content of these compounds in HDL particles by more than an order of magnitude. The susceptibility to oxidation of the HDL₂ subfraction of HDLs was higher than the susceptibility of total HDL fraction and HDL₃ subfraction. The data obtained confirm an important role of free radical peroxidation of LDLs in the molecular mechanisms of vascular wall damage in atherosclerosis.

Oxidatively modified low-density lipoproteins are potential mediators of proteasome inhibitor resistance in multiple myeloma

Proteasome inhibitor (PI) therapy has improved the survival of multiple myeloma (MM) patients. However, inevitably, primary or acquired resistance to PIs leads to disease progression; resistance mechanisms are unclear. Obesity is a risk factor for MM mortality. Oxidized LDL (OxLDL), a central mediator of atherosclerosis that is elevated in metabolic syndrome (co-occurrence of obesity, insulin resistance, dyslipidemia and hypertension), has been linked to an increased risk of solid cancers and shown to stimulate pro-oncogenic/survival signaling. We hypothesized that OxLDL is a mediator of chemoresistance and evaluated its effects on MM cell killing by PIs. OxLDL potently suppressed the ability of the boronic acid-based PIs bortezomib (BTZ) and ixazomib, but not the epoxyketone-based PI carfilzomib, to kill human MM cell lines and primary cells. OxLDL suppressed BTZ-induced inhibition of proteasome activity and induction of pro-apoptotic signaling. These cytoprotective effects were abrogated when lipid hydroperoxides (LOOHs) associated with OxLDL were enzymatically reduced. We also demonstrated the presence of OxLDL in the MM bone marrow microenvironment as well as numerous granulocytes and monocytes capable of cell-mediated LDL oxidation through myeloperoxidase. Our findings suggest that OxLDL may be a potent mediator of boronic acid-based PI resistance, particularly for MM patients with metabolic syndrome, given their elevated systemic levels of OxLDL. LDL cholesterol-lowering therapy to reduce circulating OxLDL, and pharmacologic targeting of LOOH levels or resistance pathways induced by the modified lipoprotein, could deepen the response to these important agents and offer clinical benefit to MM patients with metabolic syndrome.

Royal jelly alleviates the detrimental effects of aging on immune functions by enhancing the in vitro cellular proliferation, cytokines, and nitric oxide release in aged human PBMCS

Aging strongly delays the immunity. Our research aims to assess the in vitro effects of royal jelly (RJ) on the immune function of aged PBMCs. PBMCs were obtained from 10 healthy aged and young donors by the gradient density centrifugation method and further cultured in RPMI-1640 medium supplemented with or without RJ in the presence of Con A. Cell proliferation was assessed by MTT assay along with the measurement of interleukins, Nitric oxide (NO), Glutathione (GSH), and Malondialdehydes (MDA). Our results showed that RJ improved PBMCs proliferation significantly in the elderly subjects, accompanied by the increase in NO (p = .001) and the release of IL-2, IL-4, and IL-6 cytokines. RJ also increased the intracellular GSH (p = .001) and MDA (p = .001) levels in aged PBMCs. In young subjects, RJ enhanced PBMCs proliferation potency, IL-4, IL-6, GSH, and intracellular MDA levels but with a concomitant decrease in NO and IL-2 cytokine secretion as compared with non RJ-treated cells. In conclusion, RJ restored functions of the aged PBMCs as well as the young control subjects, indicating a beneficial effect on immune status during the aging process. PRACTICAL APPLICATIONS: Royal jelly is a well-known edible dietary compound, used traditionally to treat many diseases throughout the world. Since antiquity, it was shown to have medicinal importance. The immuno-enhancing potential of this food was largely and scientifically established by the lipid and protein fractions. The present study illustrates the anti-aging and stimulatory effects of the fresh RJ whole extract, from local Algerian honey bee: Apis mellifera intermissa, on the immunity of aged men. This study provides the experimental evidence supporting anti-immunosenesence effects of royal jelly. RJ supplementation can be used in the old age management and human age-related complications, especially, associated with the weaknesses of the immune response.

Clinical Utility of the Logarithmically Transformed Ratio of Triglycerides-to- High-Density Lipoprotein Cholesterol and Its Relationship with Other Atherosclerosis-Related Lipid Factors in Type 2 Diabetes

Background: Elevated triglyceride (TG) levels and reduced high-density lipoprotein-cholesterol (HDL-c) levels indicate lipid abnormalities, but their levels alone do not reflect the actual status of plasma atherogenicity and cardiovascular disease risk (CVD). TG and HDL-c levels directly affect the balance between plasma atherogenic and antiatherogenic factors, as well as values of the atherogenic index of plasma [AIP (logarithmically transformed ratio of TG-to-HDL-c)]. The aim of this study was to evaluate the AIP risk categories (an indicator of plasma atherogenicity) and the relationships of AIP with other atherosclerosis-related lipid parameters in patients with type 2 diabetes mellitus (T2DM) and their potential clinical utility. Methods: Standard lipid profile, AIP, and lipid hydroperoxides (LOOH) were investigated in 124 T2DM outpatients (mean age 52.7 ± 5.9 years) and 61 healthy subjects (mean age 50.9 ± 6.8 years). T2DM patients were subclassified according to the AIP risk category and glycemic control. Results: Higher levels of AIP, LOOH, and TG and lower HDL-c (all P < 0.0001) were observed in T2DM patients than in the control group. AIP positively correlated with LOOH, non-HDL-c, and the non-HDL/HDL ratio (all P < 0.0001). The TG level was strongly correlated with the LOOH level among T2DM patients (P < 0.0001). Conclusions: The close association of AIP with other atherosclerosis-related lipid factors reveals an increased plasma atherogenicity. AIP risk categories indicate the actual status of plasma atherogenicity and identify subjects who are at an increased atherogenic risk and the development of CVD. In this respect, AIP has a promising future in routine clinical practice.

The Use of Biomarkers as Alternatives to Current Animal Tests on Food Chemicals

Recent developments in biomarkers relating to the interrelationship of diet, disease and health were surveyed. Most emphasis was placed on biomarkers of deleterious effects, since these are of greatest relevance to the subject of this review. The area of greatest activity was found to be that relating to biomarkers of mutagenic, genotoxic and carcinogenic effects. This is also one of the major areas of concern in considerations of the beneficial and deleterious effects of dietary components, and also the area in which regulatory testing requires studies of the longest duration. A degree of progress has also been made in the identification and development of biomarkers relating to certain classes of target organ toxicity. Biomarkers for other types of toxicity, such as immunotoxicity, neurotoxicity, reproductive toxicity and developmental toxicity, are less developed, and further investigation in these areas is required before a comprehensive biomarker strategy can be established. A criticism that recurs constantly in the biomarker literature is the lack of standardisation in the methods used, and the lack of reference standards for the purposes of validation and quality control. It is encouraging to note the growing acknowledgement of the need for validation of biomarkers and biomarker assays. Some validation studies have already been initiated. This review puts forward proposals for criteria to be used in biomarker validation. More discussion on this subject is required. It is concluded that the use of biomarkers can, in some cases, facilitate the implementation of the Three Rs with respect to the testing of food chemicals and studies on the effects of diet on health. The greatest potential is seen to be in the refinement of animal testing, in which biomarkers could serve as early and sensitive endpoints, in order to reduce the duration of the studies and also reduce the number of animals required. Biomarkers could also contribute to establishing a mechanistic basis for in vitro test systems and to facilitating their validation and acceptance. Finally, the increased information that could result from the incorporation of biomarker determinations into population studies could reduce the need for supplementary animal studies. This review makes a number of recommendations concerning the prioritisation of future activities on dietary biomarkers in relation to the Three Rs. It is emphasised, however, that further discussions will be required among toxicologists, epidemiologists and others researching the relationship between diet and health.

Glycomacropeptide Ameliorates Indomethacin-Induced Enteropathy in Rats by Modifying Intestinal Inflammation and Oxidative Stress

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy is considered a serious and increasing clinical problem without available treatment. Glycomacropeptide (GMP) is a 64-amino acid peptide derived from milk κ-casein with numerous biological activities. The aim of this study was to investigate the protective effect of GMP on NSAID enteropathy in rats. Enteropathy was induced by seven days oral indomethacin administration. Rats were orally GMP treated from seven days previous and during the establishment of the enteropathy model. Changes in metabolism, hematological and biochemical blood alterations, intestinal inflammation and oxidative damage were analyzed. Integrity barrier markers, macroscopic intestinal damage and survival rate were also evaluated. GMP treatment prevented anorexia and weight loss in animals. Furthermore, prophylaxis with GMP ameliorated the decline in hemoglobin, hematocrit, albumin and total protein levels. The treatment had no therapeutic efficacy on the decrease of occludin and mucin (MUC)-2 expression in intestinal tissue. However, GMP markedly decreased neutrophil infiltration, and CXCL1, interleukin-1β and inducible nitric oxide synthase expression. Nitric oxide production and lipid hydroperoxide level in the small intestine were also diminished. These beneficial effects were mirrored by preventing ulcer development and increasing animal survival. These results suggest that GMP may protect against NSAID enteropathy through anti-inflammatory and antioxidant properties.

Beneficial Effects of Low-Calorie-Carbohydrate/High-Agar Diet on Cardiometabolic Disorders Associated with Non-Alcoholic Fatty Liver Disease in Obese Rats

Energy restriction and low carbohydrate diets are recommended as nutrition therapies to prevent becoming overweight or obese. However, their beneficial effects in non-alcoholic fatty liver disease (NAFLD) are less well investigated. In addition, the effects of the type of polysaccharides incorporated into these diets and their contents have been scarcely studied. Therefore, this study aimed to elucidate whether low-calorie-carbohydrate high-agar diets could improve liver metabolic dysfunction, membrane fluidity, oxidative damage, and endothelial dysfunction in obese rats. Obesity was induced by feeding rats a high-fat diet (HFD) for 10 weeks. The obese rats were then divided into two homogenous groups: the first group was fed low-calorie-carbohydrate/high-agar diet (LCC/HA) and the second continued to consume the HFD for 4 weeks [obese control (Ob-C)]. Normo-ponderal rats were fed a normal diet during the entire study, and were used as the control (N-C). Compared with the Ob-C group, body weight, hepatic lipids, low density lipoproteins cholesterol (C), the non esterified cholesterol/phospholipids ratio, serum transaminases activities, and lipid peroxidation markers (thiobarbituric acid reactive substances and lipid hydroperoxides) were reduced in LCC/HA group (P<0.05). However, the serum concentration of high density lipoproteins-C was enhanced (P<0.05). In addition, we observed improved antioxidant defence and endothelial dysfunction associated with antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase, and catalase (P<0.05), and nitric oxide level (P<0.05). These findings suggest that hypocaloric diets low in energy and carbohydrates and rich in agar may be beneficial against HFD-induced hepatic steatosis damage, and may be a promising therapeutic strategy to counteract NAFLD development associated with obesity.

Exposure of Human Gastric Cells to Oxidized Lipids Stimulates Pathways of Amino Acid Biosynthesis on a Genomic and Metabolomic Level

The Western diet is characterized by a high consumption of heat-treated fats and oils. During deep-frying processes, vegetable oils are subjected to high temperatures which result in the formation of lipid peroxidation products. Dietary intake of oxidized vegetable oils has been associated with various biological effects, whereas knowledge about the effects of structurally-characterized lipid peroxidation products and their possible absorption into the body is scarce. This study investigates the impact of linoleic acid, one of the most abundant polyunsaturated fatty acids in vegetable oils, and its primary and secondary peroxidation products, 13-HpODE and hexanal, on genomic and metabolomic pathways in human gastric cells (HGT-1) in culture. The genomic and metabolomic approach was preceded by an up-to-six-hour exposure study applying 100 µM of each test compound to the apical compartment in order to quantitate the compounds’ recovery at the basolateral side. Exposure of HGT-1 cells to either 100 µM linoleic acid or 100 µM 13-HpODE resulted in the formation of approximately 1 µM of the corresponding hydroxy fatty acid, 13-HODE, in the basolateral compartment, whereas a mean concentration of 0.20 ± 0.13 µM hexanal was quantitated after an equivalent application of 100 µM hexanal. An integrated genomic and metabolomic pathway analysis revealed an impact of the linoleic acid peroxidation products, 13-HpODE and hexanal, primarily on pathways related to amino acid biosynthesis (p < 0.05), indicating that peroxidation of linoleic acid plays an important role in the regulation of intracellular amino acid biosynthesis.

Can Indirect Herbicide Exposure Modify the Response of the Colorado Potato Beetle to an Organophosphate Insecticide?

Organisms live in complex multivariate environments. In agroecosystems, this complexity is often human-induced as pest individuals can be exposed to many xenobiotics simultaneously. Predicting the effects of multiple stressors can be problematic, as two or more stressors can have interactive effects. Our objective was to investigate whether indirect glyphosate-based herbicide (GBH) exposure of the host plant has interactive effects in combination with an insecticide (azinphos-methyl) on an invasive pest Colorado potato beetle (Leptinotarsa decemlineata Say). We tested the effects of GBH and insecticide on the survival, insecticide target genes expression (acetylcholinesterase genes) and oxidative status biomarkers (glutathione S-transferase [GST], glucose-6-phosphate dehydrogenase [G6PDH], glutathione reductase homolog [GR], glutathione peroxidase homolog [GPx], total glutathione [totGSH], glutathione reduced-oxidized [GSH: GSSG], catalase [CAT], superoxide dismutase [SOD], lipid hydroperoxides). We found that exposure to indirect GBH has no single or interactive effects in combination with the insecticide on larval survival. However, prior exposure to GBH inhibits Ldace1 gene expression by 0.55-fold, which is the target site for the organophosphate and carbamate insecticides. This difference disappears when individuals are exposed to both GBH and insecticide, suggesting an antagonistic effect. On the other hand, oxidative status biomarker scores (PCAs of GPx, GR, and CAT) were decreased when exposed to both stressors, indicating a synergistic effect. Overall, we found that indirect GBH exposure can have both antagonistic and synergistic effects in combination with an insecticide, which should be considered when aiming for an ecologically relevant risk assessment of multiple human-induced stressors.

Meta-analysis of genomic variants and gene expression data in schizophrenia suggests the potential need for adjunctive therapeutic interventions for neuropsychiatric disorders

Schizophrenia (SZ) is a debilitating mental illness with a multigenic aetiology and significant heritability. Despite extensive genetic studies, the molecular aetiology has remained enigmatic. A recent systems biology study suggested a protein-protein interaction network for SZ with 504 novel interactions. The onset of psychiatric disorders is predominant during adolescence, often accompanied by subtle structural abnormalities in multiple regions of the brain. The availability of BrainSpan Atlas data allowed us to re-examine the genes present in the SZ interactome as a function of space and time. The availability of genomes of healthy centenarians and nonpsychiatric Exome Aggregation Consortium database allowed us to identify the variants of criticality. The expression of the SZ candidate genes responsible for cognition and disease onset was studied in different brain regions during particular developmental stages. A subset of novel interactors detected in the network was further validated using gene expression data of post-mortem brains of patients with psychiatric illness. We have narrowed down the list of drug targets proposed by theprevious interactome study to 10 proteins. These proteins belonging to 81 biological pathways are targeted by 34 known Food and Drug Administration-approved drugs that have distinct potential for the treatment of neuropsychiatric disorders. We also report the possibility of targeting key genes belonging to celecoxib pharmacodynamics, Gα signalling and cGMP-PKG signalling pathwaysthat are not known to be specific to SZ aetiology.

Iron as a catalyst of human low-density lipoprotein oxidation: Critical factors involved in its oxidant properties

Iron-induced human LDL oxidation, which is relevant to atherosclerosis, has not yet been properly investigated. We addressed such issue using iron(II) and (III) basically in the presence of phosphates, which are present in vivo and influence iron oxidative properties, at pH 4.5 and 7.4, representative, respectively, of the lysosomal and plasma environment. In 10mM phosphate buffered saline (PBS), iron(II) induces substantial LDL oxidation at pH 4.5 at low micromolar concentrations, while at pH 7.4 has low oxidative effects; iron(III) promotes small LDL oxidation only at pH 4.5. In 10mM sodium acetate/NaCl buffer, pH 4.5, iron-induced LDL oxidation is far higher than in PBS, highlighting the relevance of phosphates in the inhibitory modulation of iron-induced LDL oxidation. LDL oxidation is related to iron binding to the protein and lipid moiety of LDL, and requires the presence of iron(II) bound to LDL together with iron(III). Chemical modification of LDL carboxyl groups, which could bind iron especially at pH 4.5, decreases significantly iron binding to LDL and iron-induced LDL oxidation. Hydroxyl radical scavengers are ineffective on iron-induced LDL oxidation, which is inhibited by metal chelation, scavengers of alkoxyl/peroxyl radicals, or removal of LDL lipid hydroperoxides (LOOH). Overall, substantial human LDL oxidation is induced LOOH-dependently by iron(II) at pH 4.5 even in the presence of phosphates, suggesting the occurrence of iron(II)-induced LDL oxidation in vivo within lysosomes, where pH is about 4.5, iron(II) and phosphates coexist, plasma with its antioxidants is absent, and glutathione peroxidase is poorly expressed resulting in LOOH accumulation.

Clinical association of baseline levels of conjugated dienes in low-density lipoprotein and nitric oxide with aggressive B-cell non-Hodgkin lymphoma and their relationship with immunoglobulins and Th1-to-Th2 ratio

Objective

The aim of this study was to highlight the clinical association of baseline levels of conjugated dienes in low-density lipoprotein (LDL-BCD) and nitric oxide (NO) with immunoglobulins (Igs) and T helper (Th)1/Th2 ratio in patients with newly diagnosed B-cell non-Hodgkin lymphoma (NHL).

Patients and methods

Thirty-two newly diagnosed patients with aggressive B-cell NHL and 25 age-, sex-, and body-mass-index-matched healthy controls were randomly selected for a cross-sectional case–control study conducted at the Hematology Department of Tlemcen Medical Centre University (northwest of Algeria).

Results

Circulating levels of LDL-BCD and NO and those of IgA and IgM were significantly higher in patients than in controls. The levels of Th1/Th2 ratio and plasma total antioxidant capacity were significantly lower in patients compared with controls, while malondialdehyde and protein carbonyl levels were significantly higher in patients. B-cell NHL was significantly associated with high levels of LDL-BCD from 25th to 75th percentile (25th percentile: relative risk [RR] =2.26, 95% confidence interval [CI] 1.42–3.59, P=0.014; 50th percentile: RR =2.84, 95% CI 1.72–4.68, P<0.001; 75th percentile: RR =5.43, 95% CI 2.58–11.42, P<0.001). Similarly, the disease was significantly associated with high levels of NO production from 25th to 75th percentile (25th percentile: RR =2.07, 95% CI 1.25–3.44, P=0.024; 50th percentile: RR =2.78, 95% CI 1.63–4.72, P<0.001; 75th percentile: RR =4.68, 95% CI 2.21–9.91, P<0.001). Moreover, LDL-BCD levels were positively and significantly correlated with interferon (IFN)-γ, whereas NO levels were inversely and significantly correlated with IFN-γ and Th1/Th2 ratio.

Conclusion

LDL-BCD and NO production seem to be associated with aggressive B-cell NHL and alteration of Th1/Th2 ratio. Our results have to be examined using ex vivo mechanistic studies leading to further investigations of these parameters, with an interest in the link between Epstein–Barr virus infection and NO and immunoglobulins.

The effect of compartmentalization on the kinetics of transition metal ions-induced lipoprotein peroxidation

In a previous study, we proposed characterizing the typically observed kinetic profiles of transition metal ion-induced lipid peroxidation in terms of a limited number of characteristic time-points. These time-points can be derived from experimental time-dependencies and be presented in terms of rate constants and concentrations as calculated based on mechanistic considerations. The critical part of that analysis was that we had to assume that the experimental system behaves as if it is homogeneous, i.e., as if the reaction occurs in a solution. In spite of the uncertainties due to the latter assumption, we obtained a reasonable agreement between the experimental data and the theoretically predicted dependencies, which supports our theoretical treatment. Yet, several previous findings could not have been explained in terms of our ('quasi-homogeneous') model, indicating that the model is valid not under all conditions. One example is that under certain conditions, rapid peroxidation occurs prior to complete consumption of LDL-associated tocopherol. This can be attributed to compartmentalization of residual tocopherol, namely, after the onset of propagation, part of the LDL particles contain tocopherol, whereas in the other, tocopherol-depleted particles, the PUFA may undergo rapid LOOH-accelerated peroxidation only if they contain at least two hydroperoxides molecules per particle. In the present investigation, we show that the results of all our kinetic studies can be understood if we consider compartmentalization. Specifically, for any given composition of the particles (LDL and/or HDL), the kinetic results may be governed by the distribution and rate of exchange of antioxidants and hydroperoxides between particles. Our analysis is of special importance for systems containing more than one population of lipoprotein particles.

Relationship between NADPH and Th1/Th2 ratio in patients with non-Hodgkin lymphoma who have been exposed to pesticides

The effect of pesticides on nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), including its level and relationship with the T helper 1 (Th1)/Th2 ratio, in patients suffering from non-Hodgkin lymphoma (NHL) was investigated. One hundred newly diagnosed patients with aggressive NHL (53 men, 47 women) and 40 healthy age-, sex-, and body mass index-matched controls (23 men, 17 women), exposed or not to pesticides, were recruited for a cross-sectional study conducted at the Clinical Hematology Departments of Tlemcen and Sidi Bel-Abbès University Medical Centers in the northwest of Algeria. NADPH levels were significantly increased in patients compared with controls; and in exposed patients compared with those not exposed, and controls (one-way analysis of variance; P=0.000). Albumin, glutathione peroxidase, superoxide dismutase, catalase activity, and oxygen radical absorbance capacity levels were significantly decreased in patients compared with in the control group. Oxygen radical absorbance capacity levels were significantly decreased in exposed patients compared with in unexposed patients; however, malondialdehyde levels were significantly increased in exposed patients when compared with controls and unexposed patients. Protein carbonyl and xanthine oxidase levels were significantly increased in exposed patients compared with controls; meanwhile, there were no significant differences between the two patient groups or between unexposed patients and controls. The Th1/Th2 ratio was significantly decreased in patients when compared with controls; the neutrophil-to-lymphocyte ratio was significantly increased (for both comparisons, P<0.001). In addition, NADPH was strongly associated with NHL (Mantel–Haenszel common odds ratio estimate =5.55; 95% confidence interval, 2.22–13.88; P=0.000). Moreover, NADPH levels were significantly negatively related to the Th1/Th2 ratio, either in exposed patients or in unexposed patients (respectively, r=−0.498 [P=0.004] and r=−0.327 [P=0.006]). In conclusion, pesticide exposure was strongly associated with NADPH alteration in NHL. The relationship between NADPH and Th1/Th2 ratio should focus on new therapeutic strategies for the disease.

Sequential analysis of oxidative stress markers and vitamin C status in acute bacterial osteomyelitis

In bacterial bone infections, excessively formed oxidants may result in local and systemic oxidative stress. Vitamin C is the major extracellular nonenzymatic antioxidant, also implicated in bone cells metabolism and viability. The physiological functions of vitamin C largely depend on its redox status. We sequentially assessed oxidative stress markers, hydroperoxides and malondialdehyde (MDA), total antioxidant activity (AOA), total vitamin C, ascorbic acid (Asc), and oxidized/reduced vitamin C ratio in 137 patients with acute osteomyelitis (OM). Compared to 52 healthy controls, in OM group baseline serum hydroperoxides, MDA and oxidized/reduced vitamin C ratio were higher whilst Asc and AOA were lower (P < 0.05, resp.). On the other side, total vitamin C levels in patients and controls were similar (P > 0.05), thereby suggesting a relative rather than absolute vitamin C deficiency in OM. During the follow-up, oxidative stress markers, AOA, and oxidizedreduced vitamin C ratio were gradually returned to normal, while there was no apparent change of total vitamin C concentrations. Persistently high values of oxidized/reduced vitamin C ratio and serum MDA were found in subacute OM. In conclusion, acute OM was associated with enhanced systemic oxidative stress and the shift of vitamin C redox status towards oxidized forms.

Mitigating role of thymoquinone rich fractions from Nigella sativa oil and its constituents, thymoquinone and limonene on lipidemic-oxidative injury in rats

Therapeutic role of Nigella sativa (NS) seed oil fractions, methanolic extract (ME) and volatile oil (VO) and their constituents, thymoquinone (TQ) and limonene (LMN) in relation to lipidemic-oxidative stress in Wistar rats was determined. The total phenolic contents of NS seed oil and their ME and VO extracts were 320.00 ± 3.00, 300.12 ± 0.04 and 288.41 ± 0.01 mg gallic acid equivalents per 100 g of NS oil, respectively. Their Fe(+2) chelating activities were 870.00 ± 2.00, 222.31 ± 5.80 and 38.59 ± 1.43 mg EDTA equivalents per 100 g of NS oil, respectively. These fractions and compounds exhibited strong antioxidant activities against 2,2-diphenyl-1-picryl hydrazyl, 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid, nitric oxide and hydroxyl radicals. Potential antiperoxidative effects of these fractions and compounds were also observed in liposome, and lipidemic-induced lipid peroxidation in atherogenic suspension fed rats, pretreated with 100 mg ME, 20 mg VO, 10 mg pure TQ or 200 mg LMN for 30 days. ME containing ω-6 linoleic acid and palmitic acid natural compounds was highly effective against lipidemic oxidative stress than VO extract possessing thymol and isothymol phenolic natural antioxidant compounds. TQ, principal compound shared to both the extracts. The test fractions and compounds effectively reduced the erythrocyte and liver lipid peroxidation markers, conjugated diene, lipid hydroperoxide and malondialdehyde to near normal levels in the order ME > TQ > VO > LMN, by directly counteracting free radicals as well as suppressing hepatic HMG-CoA reductase activity. Our findings demonstrated that these natural products, preferably ME possess significant antioxidant activities, and may be recommended as new potential sources of natural antioxidants.

Effect of dietary n - 3 polyunsaturated fatty acids on oxidant/antioxidant status in macrosomic offspring of diabetic rats

The aim of this work was to determine the effect of dietary n − 3 PUFA on oxidant/antioxidant status, in vitro very low and low density lipoprotein (VLDL-LDL), and VLDL-LDL-fatty acid composition in macrosomic pups of diabetic mothers. We hypothesized that n − 3 PUFA would improve oxidative stress in macrosomia. Diabetes was induced in female Wistar rats fed with the ISIO diet (control) or with the EPAX diet (enriched in n − 3 PUFAs), by streptozotocin. The macrosomic pups were killed at birth (day 0) and at adulthood (day 90). Lipid parameters and VLDL-LDL-fatty acid composition were investigated. The oxidant/antioxidant status was determined by measuring plasma oxygen radical absorbance capacity (ORAC), hydroperoxides, carbonyl proteins, and VLDL-LDL oxidation. Macrosomic rats of ISIO fed diabetic mothers showed an increase in plasma and VLDL-LDL-triglycerides and VLDL-LDL-cholesterol levels and altered VLDL-LDL-fatty acid composition. Plasma ORAC was low with high hydroperoxide and carbonyl protein levels. The in vitro oxidizability of VLDL-LDL was enhanced in these macrosomic rats. The EPAX diet corrected lipid parameters and improved oxidant/antioxidant status but increased VLDL-LDL susceptibility to oxidation. Macrosomia is associated with lipid abnormalities and oxidative stress. n − 3 PUFA exerts favorable effects on lipid metabolism and on the oxidant/antioxidant status of macrosomic rats. However, there are no evident effects on VLDL-LDL oxidation.

Flavonoid rich extract of Murraya Koenigii alleviates in-vitro LDL oxidation and oxidized LDL induced apoptosis in raw 264.7 Murine macrophage cells

Several lines of evidences have established a lineage between Oxidised LDL (Ox-LDL) to apoptosis of macrophages in which the high level of intracellular cholesterol play a crucial role. This study assesses the potency of Murraya koenigii (MK) leaf extract in alleviating LDL oxidation and Ox-LDL induced lipotoxicity in murine macrophage (RAW 264.7) cells. Results indicated that presence of MK extract prevented oxidation of LDL as evidenced by its oxidation kinetics and formation of LDL oxidation products. Also, MK extract accounted for improvement in cell viability and mitochondrial membrane potential of Ox-LDL treated cells. The Ox-LDL induced increment in intracellular oxidative stress, nuclear condensation and apoptosis was effectively prevented by MK extract possibly due to their established anti-oxidant and free radical scavenging potentials which may be attributed to the presence of flavonoids present in the extract. Prevention of oxidative modification of LDL, free radical induced damage and Ox-LDL induced death of RAW 264.7 cells provide preliminary evidences of its anti-atherosclerotic potential and warrants further elucidation and validation for its use in-vivo and may be useful as a functional food supplement and an alternative medicine to prevent LDL oxidation and oxidized LDL induced toxicity.

Protective effect of Pterostilbene against free radical mediated oxidative damage

Background

Pterostilbene, a methoxylated analog of Resveratrol, is gradually gaining more importance as a therapeutic drug owing to its higher lipophilicity, bioavailability and biological activity than Resveratrol. This study was undertaken to characterize its ability to scavenge free radicals such as superoxide, hydroxyl and hydrogen peroxide and to protect bio-molecules within a cell against oxidative insult.

Methods

Anti-oxidant activity of Pterostilbene was evaluated extensively by employing several in vitro radical scavenging/inhibiting assays and pulse radiolysis study. In addition, its ability to protect rat liver mitochondria against tertiary-butyl hydroperoxide (TBHP) and hydroxyl radical generated oxidative damage was determined by measuring the damage markers such as protein carbonyls, protein sulphydryls, lipid hydroperoxides, lipid peroxides and 8-hydroxy-2'-deoxyguanosine. Pterostilbene was also evaluated for its ability to inhibit •OH radical induced single strand breaks in pBR322 DNA.

Result

Pterostilbene exhibited strong anti-oxidant activity against various free radicals such as DPPH, ABTS, hydroxyl, superoxide and hydrogen peroxide in a concentration dependent manner. Pterostilbene conferred protection to proteins, lipids and DNA in isolated mitochondrial fractions against TBHP and hydroxyl radical induced oxidative damage. It also protected pBR322 DNA against oxidative assault.

Conclusions

Thus, present study provides an evidence for the strong anti-oxidant property of Pterostilbene, methoxylated analog of Resveratrol, thereby potentiating its role as an anti-oxidant.

Carbamoylation abrogates the antioxidant potential of hydrogen sulfide

Hydrogen sulfide (H2S) has been identified as the third gasotransmitter. Beside its role as signaling molecule in the cardiovascular and nervous system the antioxidant and cyto-protective properties of H2S have gained much attention. In the present study we show that cyanate, an uremic toxin which is found in abundant concentration in sera of patients suffering from chronic kidney disease (CKD), can abrogate the antioxidant and cytoprotective activity of H2S via S-carbamoylation reaction, a reaction that previously has only been shown to have a physiological effect on cysteine groups, but not on H2S. Carbamoylation strongly inhibited the free radical scavenging (ABTS(+·) and alkylperoxyl ROO(·)) properties of H2S. The extent of intracellular ROS formation induced by ROO(·) was diminished by H2S whereas carbamoylation counteracted the protective effect. Reagent HOCl was rapidly inactivated by H2S in contrast to the carbamoylated compound. Protein modification by HOCl was inhibited by H2S but carbamoylation significantly reduced the effect. Thus, S-carbamoylation of low molecular weight thiols by abrogating their antioxidant potential may contribute to the higher oxidative stress observed in CKD.

The role of xanthine oxidase in hemodialysis-induced oxidative injury: relationship with nutritional status

The role of xanthine oxidase (XOD) in patients undergoing chronic hemodialysis treatment (HD) is poorly understood. Geriatric nutritional risk index (GNRI) ≤ 90 could be linked with malnutrition-inflammation complex syndrome. This study measured XOD, myeloperoxidase (MPO), superoxide dismutase (SOD), lipid hydroperoxides, total free thiol groups, and advanced oxidation protein products (AOPP) in 50 HD patients before commencing (pre-HD) and immediately after completion of HD session (post-HD) and in 22 healthy controls. Pre-HD serum hydroperoxides, AOPP, XOD, and SOD were higher and total thiol groups were lower in patients than in controls (P < 0.05, resp.). Compared to baseline values, serum MPO activity was increased irrespective of GNRI status. Serum XOD activity was increasing during HD treatment in the group with GNRI ≤ 90 (P = 0.030) whilst decreasing in the group with GNRI > 90 (P = 0.002). In a multiple regression analysis, post-HD serum XOD activity was independently associated with GNRI ≤ 90 (β  ± SE: 0.398 ± 0.151; P = 0.012) and HD vintage (β  ± SE: −0.349 ± 0.139; P = 0.016). These results indicate that an upregulated XOD may be implicated in HD-induced oxidative injury contributing to accelerated protein damage in patients with GNRI ≤ 90.

Method for the simultaneous determination of free/protein malondialdehyde and lipid/protein hydroperoxides

A simple and sensitive method is presented for the simultaneous quantification (spectrophotometric and spectrofluorimetric) of the main lipid and protein peroxidation products after their initial fractionation: free malondialdehyde (FrMDA), protein-bound malondialdehyde (PrMDA), total hydroperoxides (LOOH), and protein hydroperoxides (PrOOH). FrMDA and PrMDA (released from proteins by alkaline hydrolysis) are measured after the reaction of MDA with thiobarbituric acid (TBA) under acidic conditions, by the specific fluorimetric quantification of the resulting MDA-(TBA)2 adduct chromophore. The measurement of LOOH and PrOOH is based on the reaction of Fe(3+) (resulting from the reaction of LOOH and PrOOH with Fe(2+)) with xylenol orange (XO) and the photometric quantification of the resulting XO-Fe complex. The sensitivity of the assays for FrMDA/PrMDA and LOOH/PrOOH is 20 and 100pmol, respectively. The method was applied successfully on human plasma and can be used for the evaluation of oxidative stress in both basic and clinical research.

Coriandrum sativum L. seed extract mitigates lipotoxicity in RAW 264.7 cells and prevents atherogenic changes in rats

This study was designed to assess the efficacy of Coriandrum sativum L. (CS) in preventing in vitro low density lipoprotein (LDL) oxidation mediated macrophage modification. Further, an in vivo study was also conducted to confirm upon the efficacy of CS seed extract in alleviating pathophysiological alterations of high cholesterol diet induced atherosclerosis in rats. Copper mediated cell free oxidation of LDL accounted for elevated indices of malondialdehyde (MDA), lipid hydroperoxide (LHP)and protein carbonyl (PC) and a progressive increment in conjugate diene (CD) levels whereas, reverse set of changes were recorded in presence of CS extract. Cell mediated LDL oxidation (using RAW 264.7 cells) accounted for lowered MDA production and oxidized LDL (Ox-LDL) mediated cell death in presence of CS extract and the same was attributed to its potent antioxidant and free radical scavenging potentials. High cholesterol fed atherogenic rats showed elevated lipid indices, evidences of LDL oxidation, plaque formation in thoracic aorta. The same was further validated with immunostaining of cell adhesion molecules and hematoxylin and eosin (HXE) staining. However, co-supplementation of CS to atherogenic rats recorded significant lowering of the above mentioned parameters further strengthening the claim that CS extract is instrumental in preventing onset and progression of atherosclerosis.

Protection by polyphenols of postprandial human plasma and low-density lipoprotein modification: the stomach as a bioreactor

Recent studies dramatically showed that the removal of circulating modified low-density lipoprotein (LDL) results in complete prevention of atherosclerosis. The gastrointestinal tract is constantly exposed to food, some of it containing oxidized compounds. Lipid oxidation in the stomach was demonstrated by ingesting heated red meat in rats. Red wine polyphenols added to the rats' meat diet prevented lipid peroxidation in the stomach and absorption of malondialdehyde (MDA) in rat plasma. In humans, postprandial plasma MDA levels rose by 3-fold after a meal of red meat cutlets. MDA derived from meat consumption caused postprandial plasma LDL modification in human. The levels of plasma MDA showed a 75% reduction by consumption of red wine polyphenols during the meat meal. Locating the main biological site of action of polyphenols in the stomach led to a revision in the understanding of how antioxidants work in vivo and may help to elucidate the mechanism involved in the protective effects of polyphenols in human health.

Alteration of antioxidant defense status precedes humoral immune response abnormalities in macrosomia

Background

This study aimed to investigate whether the anomalies affecting the antioxidant and humoral immune defenses could start at birth and to check whether the decrease in antioxidant defenses may precede the immune abnormalities in macrosomic newborns.

Material/Methods

Thirty macrosomic and 30 sex-matched control newborns were recruited for a retrospective case-control study at the Maghnia Maternity Hospital of Tlemcen Department (Algeria).

Results

The serum IgG levels were similar in both groups. However, plasma ORAC, albumin, vitamin E, SOD, CAT and GSH-Px levels were significantly decreased in macrosomic as compared to control newborns, yet no difference was observed after adjustment for weight. Additionally, serum concentrations of complement C3, MDA and XO were significantly higher in macrosomic as compared to controls before adjustment for weight. Moreover, macrosomia was significantly associated with high levels of complement C3 (OR=8, p=0.002); whereas no association with those of IgG was observed (OR<1, p>0.05). Furthermore, macrosomia was significantly associated with low levels of ORAC (OR=4.96, p=0.027), vitamin E (OR=4.5, p=0.018), SOD (OR=6.88, p=0.020) and CAT (OR=5.67, p=0.017), and with high levels of MDA (OR=10.29, p=0.005).

Conclusions

Abnormalities of the humoral defense system in excessive weight could be preceded by alterations of the anti-oxidative defense and by inflammatory response and activation of innate immunity at birth. Additionally, excessive weight could be a potential factor contributing to decreased anti-oxidative capacity and increased oxidative stress.

Argan oil improves surrogate markers of CVD in humans

Limited – though increasing – evidence suggests that argan oil might be endowed with potential healthful properties, mostly in the areas of CVD and prostate cancer. We sought to comprehensively determine the effects of argan oil supplementation on the plasma lipid profile and antioxidant status of a group of healthy Algerian subjects, compared with matched controls. A total of twenty healthy subjects consumed 15 g/d of argan oil – with toasted bread – for breakfast, during 4 weeks (intervention group), whereas twenty matched controls followed their habitual diet, but did not consume argan oil. The study lasted 30 d. At the end of the study, argan oil-supplemented subjects exhibited higher plasma vitamin E concentrations, lower total and LDL-cholesterol, lower TAG and improved plasma and cellular antioxidant profile, when compared with controls. In conclusion, we showed that Algerian argan oil is able to positively modulate some surrogate markers of CVD, through mechanisms which warrant further investigation.

The biological relevance of direct antioxidant effects of polyphenols for cardiovascular health in humans is not established

Human studies provide evidence for beneficial effects of polyphenol-rich foods on cardiovascular health. The antioxidant activity of polyphenols potentially explains these effects, but is the antioxidant activity a reliable predictor for these effects? An International Life Sciences Institute Europe working group addressed this question and explored the potential of antioxidant claims for polyphenols in relation to cardiovascular health by using the so-called Process for the Assessment of Scientific Support for Claims on Foods project criteria. In this process, analytical aspects of polyphenols, their occurrence in foods, dietary intake, and bioavailability were reviewed. Human studies on polyphenols and cardiovascular health were reviewed together with methods for biomarkers of oxidative damage and total antioxidant capacity (TAC). In retrospective studies, F2-isoprostanes and oxidized LDL, the most reliable biomarkers of lipid peroxidation, and measures for TAC showed the expected differences between cardiovascular disease patients and healthy controls, but prospective studies are lacking, and a causal relationship between these biomarkers and cardiovascular health could not be established. Therefore, the physiological relevance of a potential change in these biomarkers is unclear. We found limited evidence that some types of polyphenol-rich products modify these biomarkers in humans. A direct antioxidant effect of polyphenols in vivo is questionable, however, because concentrations in blood are low compared with other antioxidants and extensive metabolism following ingestion lowers their antioxidant activity. Therefore, the biological relevance of direct antioxidant effects of polyphenols for cardiovascular health could not be established. Overall, although some polyphenol-rich foods exert beneficial effects on some biomarkers of cardiovascular health, there is no evidence that this is caused by improvements in antioxidant function biomarkers (oxidative damage or antioxidant capacity).

Clerodendron glandulosum.Coleb extract ameliorates high fat diet/fatty acid induced lipotoxicity in experimental models of non-alcoholic steatohepatitis

This study evaluates the protective role of Clerodendron glandulosum.Coleb (CG) aqueous extract against high fat diet/fatty acid induced lipotoxicity in experimental models of non-alcoholic steatohepatitis (NASH). Supplementation of NASH mice with CG extract (1% and 3% in high fat diet for 16 weeks) prevented high fat diet induced elevation in liver enzymes, plasma and hepatic lipids, mitochondrial oxidative stress and compromised enzymatic and non-enzymatic antioxidant status and histopathological damage to hepatocytes. Furthermore, results from in vitro study indicates, addition of CG extract (20-200 μg/ml for 24h) to HepG2 cells minimizes oleic acid induced lipid accumulation, higher lipid peroxidation, cytotoxicity and reduced cell viability. These in vivo and in vitro studies suggest that CG extract has the potential of preventing high fat/fatty acid induced NASH.

Oxidant/antioxidant status, lipids and hormonal profile in overweight women with breast cancer

This study was carried out to determine the relationships between leptin concentrations, lipid alterations, oxidant/ antioxidant status, in vitro LDL oxidizability and LDL-fatty acid composition in overweight breast cancer patients. Glucose, insulin, leptin, lipids, LDL-cholesteryl ester fatty acids, markers of oxidant status (MDA, Hydroperoxides, carbonyl proteins, conjugated dienes) and markers of antioxidant status (vitamins A, C, E, erythrocyte activities of the enzymes superoxide dismutase, SOD, catalase, glutathione peroxidase,GPx, and glutathione reductase, GR and the serum total antioxidant status, ORAC) were investigated in breast cancer patients and in control women. Our findings showed that insulin, leptin, triglyceride, cholesterol and LDL-C concentrations were increased in patients compared to controls. ORAC and vitamin C and E values were lower while plasma hydroperoxide, carbonyl protein and conjugated diene levels, SOD and GPx activities were higher than in controls. Alterations in LDL-fatty acid composition were associated with their enhanced oxidative susceptibility. There were significant positive correlations between leptin concentrations and LDL-C, hydroperoxides, carbonyl proteins, SOD activity, baseline conjugated diene levels and oxidation rate, and significant negative correlations between leptin and ORAC, lag time and LDL-PUFA in patients. In conclusion, breast cancer is associated with lipid alterations and enhanced oxidative stress linked to high leptin levels in overweight.

Traditional reactive carbonyl scavengers do not prevent the carbonylation of brain proteins induced by acute glutathione depletion

This study investigated the effect of reactive carbonyl species (RCS)-trapping agents on the formation of protein carbonyls during depletion of brain glutathione (GSH). To this end, rat brain slices were incubated with the GSH-depletor diethyl maleate in the absence or presence of chemically different RCS scavengers (hydralazine, methoxylamine, aminoguanidine, pyridoxamine, carnosine, taurine and z-histidine hydrazide). Despite their strong reactivity towards the most common RCS, none of the scavengers tested, with the exception of hydralazine, prevented protein carbonylation. These findings suggest that the majority of protein-associated carbonyl groups in this oxidative stress paradigm do not derive from stable lipid peroxidation products like malondialdehyde (MDA), acrolein and 4-hydroxynonenal (4-HNE). This conclusion was confirmed by the observation that the amount of MDA-, acrolein- and 4-HNE-protein adducts does not increase upon GSH depletion. Additional studies revealed that the efficacy of hydralazine at preventing carbonylation was due to its ability to reduce oxidative stress, most likely by inhibiting mitochondrial production of superoxide and/or by scavenging lipid free radicals.

Photochemistry of bacteriochlorophylls in human blood plasma: 1. Pigment stability and light-induced modifications of lipoproteins

Transmetalated derivatives of bacteriochlorophyll are promising sensitizers in photodynamic therapy. Protocols using short delay times between injection and irradiation cause interest in the photochemistry of these pigments in the blood. Using near-infrared irradiation where these pigments absorb strongly, we have studied the photochemistry of Zn- and Pd-bacteriopheophorbide (WST09), and of the highly polar taurinated Pd-derivative, WST11, in isolated fractions of human blood plasma. The stability of all pigments is increased in blood plasma, compared with monomeric solutions. Pd-bacteriopheophorbide is much more stable than the other two derivatives. It also has a higher capacity for inducing reactive oxygen species, yet the consumption of oxygen is comparable. There is furthermore evidence for photobleaching under anoxic conditions. The generation of hydroperoxides (ROOH) is faster with Pd- than with Zn-complexes; the formation of endoperoxides (ROOR'), measured as thiobarbituric acid reactive substances, is comparable with the two central metals. Formation of both ROOH and ROOR' is increased in low-density lipoproteins (LDL) compared with high-density lipoproteins (HDL), which is probably related to the higher concentration of target molecules in the former. In HDL, extensive cross-linking is induced among the apolipoproteins; judged from the electrophoretic mobility of LDL and HDL particles, there is also a gross structural change. Photosensitized cross-linking is much less pronounced with high-density proteins.

Free radical scavenging and antiatherogenic activities of Sesamum indicum seed extracts in chemical and biological model systems

An emerging consensus underscores the importance of oxidative events in vascular disease including excess production of reactive oxygen/nitrogen species (ROS/RNS), in addition to lipoprotein oxidation. Sesamum indicum has long been used extensively as a traditional food. The aim of present study was to evaluate antioxidant action of aqueous and ethanolic seed extracts from S. indicum using various in vitro ROS/RNS generated chemical and biological models. Results demonstrated that the graded-dose (25-1000 microg/ml) of aqueous and ethanolic extracts markedly scavenged the nitric oxide, superoxide, hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, showed metal chelating ability as well as reducing capacity in Fe(3+)/ferricyanide complex and ferric reducing antioxidant power assays. In biological models, both extracts were found to inhibit metal-induced lipid peroxidation in mitochondrial fractions, human serum and LDL oxidation models. In lipoprotein kinetics study, both extracts significantly (P<0.05) increased lag phase time along with reduced oxidation rate and conjugated dienes production. Ethanolic extract of S. indicum showed higher amounts of total polyphenol and flavonoid content as compared to their counterpart. The IC(50) values of both extracts were compared with respective antioxidant standards. Overall, ethanolic extract of S. indicum possess strong antioxidant capacity and offering effective protection against LDL oxidation susceptibility.

Hydrogen sulphide: A novel physiological inhibitor of LDL atherogenic modification by HOCl

Hypochlorite (HOCl), the product of the activated myeloperoxidase/H(2)O(2)/chloride (MPO/H(2)O(2)/Cl(- )) system is favored as a trigger of LDL modifications, which may play a pivotal role in early atherogenesis. As HOCl has been shown to react with thiol-containing compounds like glutathione and N-acetylcysteine protecting LDL from HOCl modification, we have tested the ability of hydrogen sulfide (H(2)S) - which has recently been identified as an endogenous vasorelaxant - to counteract the action of HOCl on LDL. The results show that H(2)S could inhibit the atherogenic modification of LDL induced by HOCl, as measured by apolipoprotein alterations. Beside its HOCl scavenging potential, H(2)S was found to inhibit MPO (one may speculate that this occurs via H(2)S/heme interaction) and destroy H(2)O(2). Thus, H(2)S may interfere with the reactants and reaction products of the activated MPO/H(2)O(2)/Cl(- ) system. Our data add to the evidence of an anti-atherosclerotic action of this gasotransmitter taking the role of HOCl in the atherogenic modification of LDL into account.