Arachidonic acid-induced malondialdehyde formation in rat platelets. Kinetic aspects and inhibition by acetylsalicylic acid and indomethacin

GC-MS and GC-MS/MS measurement of malondialdehyde (MDA) in clinical studies: Pre-analytical and clinical considerations

Malondialdehyde (MDA; 1,3-propanedial, OHC-CH2-CHO) is one of the most frequently measured biomarkers of oxidative stress in plasma and serum. L-Arginine (Arg) is the substrate of nitric oxide synthases (NOS), which convert L-arginine to nitric oxide (NO) and L-citrulline. The Arg/NO pathway comprises several members, including the endogenous NOS-activity inhibitor asymmetric dimethylarginine (ADMA) and its major metabolite dimethyl amine (DMA), and nitrite and nitrate, the major NO metabolites. Reliable measurement of MDA and members of the Arg/NO pathway in plasma, serum, urine and in other biological samples, such as saliva and cerebrospinal fluid, is highly challenging both for analytical and pre-analytical reasons. In our group, we use validated gas chromatography-mass spectrometry (GC-MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) methods for the quantitative determination in clinical studies of MDA as a biomarker of oxidative stress, and various Arg/NO metabolites that describe the status of this pathway. Here, the importance of pre-analytical issues, which has emerged from the use of GC-MS and GC-MS/MS in clinico-pharmacological studies, is discussed. Paradigmatically, two studies on the long-term oral administration of L-arginine dihydrochloride to patients suffering from peripheral arterial occlusive disease (PAOD) or coronary artery disease (CAD) were considered. Pre-analytical issues that were addressed include blood sampling, plasma or serum storage, study design (notably in long-term studies), and the alternative of measuring MDA in human urine.

Multiomics analyses uncover nanoceria triggered oxidative injury and nutrient imbalance in earthworm Eisenia fetida

The toxic stress caused by nanoceria remains vague owing to the limited efforts scrutinizing its molecular mechanisms. Herein, we investigated the impacts of nanoceria on earthworm Eisenia fetida, at the molecular level using the multiomics-based profiling approaches (transcriptomics, metabolomics, and 16 S rRNA sequencing). Nanoceria (50 and 500 mg/kg) significantly increased the contents of malondialdehyde (MDA), Fe, and K in worms, suggesting oxidative injury and nutrient imbalance. This was corroborated by the transcriptomic and metabolomic analyses. Nanoceria decreased the levels of certain genes and metabolites associated with glycerolipid and glycerophospholipid metabolisms, suggesting the production of reactive oxygen species and subsequent oxidative stress. Additionally, the ABCD3 gene belonging to ABC transporter family was upregulated, facilitating Fe uptake by worms. Moreover, the higher contents of MDA, Fe, and K after exposure were tightly associated with the imbalanced intestinal flora. Specifically, a higher relative abundance of Actinobacteriota and a lower relative abundance of Proteobacteria and Patescibacteria were induced. This study, for the first time, revealed that nanoceria at nonlethal levels caused oxidative stress and nutrient imbalance of earthworms from the perspective of genes, metabolites, and gut microbiome perturbations, and also established links between the gut microbiome and the overall physiological responses of the host.

Isa WYH. An Evaluation of the Role of Oxidative Stress in Non-Obstructive Coronary Artery Disease

Approximately half of all women presenting to the emergency department with angina chest pain do not have obstructive coronary artery disease (CAD) on coronary angiography. This condition is termed non-obstructive coronary artery disease (NOCAD), and includes ischemia with no obstructive coronary artery disease (INOCA) and myocardial infarction with non-obstructive coronary arteries (MINOCA). Oxidative stress has been reported to be involved in the development and progression of CAD. However, a scarcity of studies has assessed a correlation between oxidative stress and NOCAD. Thus, a literature review was performed of available reports on the role of oxidative stress in NOCAD. Possible mechanisms involved in oxidative stress that may contribute to NOCAD were identified and evaluated. A key finding of this literature review was that oxidative stress caused vasoconstriction and endothelial damage, and this results in coronary microvascular dysfunction and vasospasm, which, in turn, lead to the pathogenesis of NOCAD.

Lower blood malondialdehyde is associated with past pesticide exposure: findings in Gulf War illness and healthy controls

BACKGROUND

Malondialdehyde (MDA) is a candidate general marker of oxidative stress (OS). We sought to assess the relation of MDA to Gulf War illness (GWI) and to a variety of exposures.

METHODS

This is an observational study involving subjects from Southern California recruited from October 2011 to May 2014. MDA was assessed in 81 participants (41 GWI-cases, 40 controls). General and Gulf-specific exposures were elicited. MDA case-control comparison was restricted to 40 matched pairs. The potential association between MDA and exposures was assessed using regression analyses. Gulf-specific exposures were incorporated into a case-specific model.

RESULTS

Plasma MDA was significantly lower in GWI-cases than controls. Composite pesticide and fuel-solvent exposures negatively predicted MDA in the total sample, as well as in the analyses that included either GWI-cases or controls only. Self-reported exposure to organophosphate (OP) nerve gas was a strong predictor for lower MDA level in veterans with GWI.

CONCLUSION

Past pesticide exposures predicted lower MDA in both veterans with GWI and in healthy controls.

Assessment of lipid peroxidation by measuring malondialdehyde (MDA) and relatives in biological samples: Analytical and biological challenges

Malondialdehyde (MDA), 4-hydroxy-nonenal (HNE) and the F₂-isoprostane 15(S)-8-iso-prostaglandin F_2α (15(S)-8-iso-PGF_2α) are the best investigated products of lipid peroxidation. MDA, HNE and 15(S)-8-iso-PGF_2α are produced from polyunsaturated fatty acids (PUFAs) both by chemical reactions and by reactions catalyzed by enzymes. 15(S)-8-iso-PGF_2α and other F₂-isoprostanes are derived exclusively from arachidonic acid (AA). The number of PUFAs that may contribute to MDA and HNE is much higher. MDA is the prototype of the so called thiobarbituric acid reactive substances (TBARS). MDA, HNE and 15(S)-8-iso-PGF_2α are the most frequently measured biomarkers of oxidative stress, namely of lipid peroxidation. In many diseases, higher concentrations of MDA, HNE and 15(S)-8-iso-PGF_2α are measured in biological samples as compared to health. Therefore, elevated oxidative stress is generally regarded as a pathological condition. Decreasing the concentration of biomarkers of oxidative stress by changing life style, by nutritional intake of antioxidants or by means of drugs is generally believed to be beneficial to health. Reliable assessment of oxidative stress by measuring MDA, HNE and 15(S)-8-iso-PGF_2α in biological fluids is highly challenging for two important reasons: Because of the duality of oxidative stress, i.e., its origin from chemical and enzymatic reactions, and because of pre-analytical and analytical issues. This article focuses on these key issues. It reviews reported analytical methods and their principles for the quantitative measurement of MDA, HNE and 15(S)-8-iso-PGF_2α in biological samples including plasma and urine, and critically discusses their biological and biomedical outcome which is rarely crystal clear and free of artefacts.

Inhibitory effect of aryl thienyl-ketones and -thioketones on arachidonic acid-induced malondialdehyde formation in human platelets: biological data and molecular modelling

A series of anti-thrombotic aryl thienyl-ketones and -thioketones was assayed in vitro for their inhibitory effect on malondialdehyde (MDA) production induced by arachidonic acid in human platelets. For several compounds MDA formation was strongly inhibited indicating that the anti-platelet target was situated on the cyclooxygenase pathway. A comparison between the inhibition constant Ki and the IC50 values revealed competitive inhibition kinetics. The molecular structure of one active compound was analysed by X-ray diffraction and theoretical calculations to provide information on its electronic and lipophilic properties.

Measurement of malonyldialdehyde production during sodium arachidonate-induced polymorphonuclear leukocyte aggregation

Sodium arachidonate stimulated canine polymorphonuclear leukocytes (PMNs) to aggregate and produce malonyldialdehyde (MDA). The MDA production was due to cellular processes during the aggregation, as boiled PMN suspension neither aggregated nor produced MDA. Aggregation and MDA production were not due to platelet contamination because epinephrine and ADP were unable to stimulate either of these responses in the PMN suspensions. Finally, use of the aggregatory modifiers indomethacin, 1-methylimidazole, and vitamin E dissociated aggregation from MDA production. These results suggest that the cellular process(es) resulting in MDA production is/are not responsible for canine PMN aggregation.

Effect of SAS 650 (Furofenac) on malondialydehyde production by platelets

The activity of SAS 650, a new anti-inflammatory drug, on ex vivo and in vitro MDA production by platelets was compared to that of aspirin. The drug induced dose-dependent inhibition of in vitro MDA production by rat and guinea-pig platelets and also had good activity after 30 second of incubation in rat platelets, quicker than aspirin. SAS 650 preincubation reduced the in vitro inhibitory effect of ASA, as shown also by ex vivo experiments. The results of the present study support the involvement of SAS 650 in the platelet cyclooxygenase pathway.

Antithrombotic activity of a glycosaminoglycan (sulodexide) in rats

Glycosaminoglycans extracted from various sources are extensively utilized in the treatment of occlusive vascular disease. These products have shown to possess antithrombotic activity in some experimental thrombosis (1,2). Our purpose was to study the activity of Sulodexide, an heparin-like compound (3,4), on rat model of arterial thrombosis and to study its interaction with platelets.

Differential effects of itanoxone--a new hypolipidemic and hypouricemic drug--on platelet and vascular prostaglandin generation in rats

Itanoxone ((chloro-2'-diphenyl)-4-oxo-4 methylene 2-butyric acid), a newly developed, hypolipidemic and hypouricemic compound with moderate anti-inflammatory activity, showed a short-lived, dose-dependent (20--200 mg/kg, orally), apparently competitive inhibition of platelet malondialdehyde (MDA), stimulated by either thrombin or arachidonic acid. Repeated doses did not result in any cumulative effect. At doses which completely blocked MDA production, itanoxone also inhibited thrombin-stimulated thromboxane B2 production in platelets but had no measurable effect on vascular prostacyclin generation. Pretreatment with itanoxone partially prevented the inhibitory effect of aspirin on both platelet and vascular prostaglandin synthesis. This suggests that itanoxone--like aspirin--acts at the level of cyclo-oxygenase but with greater selectivity on the platelet enzyme. This pharmacological activity is of great theoretical interest for the potential use of this compound as an antithrombic drug.