Matrix effect in F₂-isoprostanes quantification by HPLC-MS/MS: a validated method for analysis of iPF₂α-III and iPF₂α-VI in human urine

LC-MS/MS based analytical strategies for the detection of lipid peroxidation products in biological matrices

Oxidative stress (OS) arises mainly from exposure to reactive oxygen species (ROS) such as superoxide anion, hydroxyl radical, and hydrogen peroxide. These molecules can cause significant damage to proteins, DNA, and lipids, leading to various diseases. Cells fight ROS with detoxifying enzymes; however, an imbalance can cause damage leading to ischemic conditions, heart disease progression, and neurological disorders such as Alzheimer's disease. Accurate assessment of OS levels is then crucial and oxidized lipidic products are considered relevant OS biomarkers. In fact, lipids are particularly prone to ROS attack, leading to lipid peroxidation, cell membrane damage, and toxic by-products affecting DNA, proteins, and low-density lipoproteins. This review reports on recent advances in LC-MS/MS approaches for OS lipidic biomarkers, focusing on overcoming analytical challenges. 3 different classes of biomarkers have been reported, malondialdehyde, isoprostanes and oxidised sterols. For each class, the main analytical challenges with a particular focus on derivatisation procedure, sensitivity, matrix effect, ionisation have been described and discussed. The recent advancements of the LC-MS-MS procedures move towards simpler approaches, reducing errors and improving the reliability of the measurement thus enabling a comprehensive and robust OS assessment.

Multi-sample analytical workflow for the determination of isoprostanes in oral fluid: A new tool for non-invasive evaluation of oxidative stress

Oxidative stress is a pathological condition that contributes to the onset of various diseases. In this way, studying oxidative stress could lead to significant discoveries in the field of therapeutic and preventive medicine. Lipid peroxidation is the most significant event in the oxidative stress process and the gold standard biomarkers for endogenous oxidative damage to lipids are isoprostanes (IsoPs). This project aims to develop a reliable analytical method for the liquid-liquid microextraction technique, parallel artificial liquid membrane extraction (PALME) and LC-MS/MS analysis. PALME allowed to obtain a significant enrichment factor and, at the same time, a good sample purification by removing compounds that cause signal suppression, thereby reducing matrix effect. The chromatographic and mass spectrometric conditions have been fine tuned to improve the sensitivity of the method and therefore obtaining very low LOD and LOQ values. The recovery values obtained for the analytes are slightly above 50 %, except for 6-keto Prostaglandin F1A (24 %). Matrix effects were ≤ -10 %, with LODs ranging between 1 and 5 pg mL-1. The developed method is characterized by high sensitivity and low consumption of organic solvents, according to the principles of Green Analytical Chemistry and enables the determination of basal levels of IsoPs in oral fluid by processing 96 samples simultaneously.

Role of ultra-processed foods in modulating the effect of Mediterranean diet on human and planet health-study protocol of the PROMENADE randomized controlled trial

BACKGROUND

The Mediterranean diet (MD), globally recognized for its sustainability and health benefits, traditionally emphasizes the consumption of plant-based foods in raw or minimally processed forms. However, shifting lifestyles, even in Mediterranean regions, have led to an increasing consumption of ultra-processed foods (UPF). Epidemiological evidence suggests that UPF consumption may be detrimental to human health, but there is only one clinical trial on this topic which is largely debated in the scientific community. This study aims to investigate the impact of the inclusion of UPF within a Mediterranean-based dietary pattern on cardiometabolic markers, gut microbiota, and other markers of human and planet health.

METHODS

Fifty clinically healthy individuals showing overweight and presenting a low-to-moderate cardiovascular risk profile will be recruited for a 7-month randomized, open, cross-over dietary trial. Eligible participants will be randomly assigned to a 3-month high-UPF MD (intervention group) or a low-UPF MD (control group), with a 1-month wash-out period. Both intervention diets will have identical food group compositions, with the intervention group consuming 5 servings/day of selected UPF items, and the control group consuming raw/minimally processed items from the same food group. Blood, urine, and fecal samples, alongside food/lifestyle diaries, will be collected from each participant before and after the dietary interventions. The primary endpoint will be the change in plasma LDL-cholesterol levels from baseline. Additional markers include blood pressure, anthropometric parameters, chemical parameters, glucose and lipid-related metabolic markers, incretins, inflammatory and oxidative stress markers, fecal microbiota composition, and short-chain fatty acids. Finally, food waste production will be evaluated through specific validated food diaries. The study has been approved by the Ethical Committee of the University of Milan and the Tuscany Regional Ethics Committee of the Azienda Ospedaliera Universitaria (AOU) - Careggi, Florence.

DISCUSSION

Results from the PROMENADE study will improve knowledge about the impact of UPF consumption on human and planet health and will contribute to the scientific debate on this topic.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06314932. Registered on March 13, 2024.

Aflatoxin detection technologies: recent advances and future prospects

Aflatoxins have posed serious threat to food safety and human health. Therefore, it is important to detect aflatoxins in samples rapidly and accurately. In this review, various technologies to detect aflatoxins in food are discussed, including conventional ones such as thin-layer chromatography (TLC), high performance liquid chromatography (HPLC), enzyme linked immunosorbent assay (ELISA), colloidal gold immunochromatographic assay (GICA), radioimmunoassay (RIA), fluorescence spectroscopy (FS), as well as emerging ones (e.g., biosensors, molecular imprinting technology, surface plasmon resonance). Critical challenges of these technologies include high cost, complex processing procedures and long processing time, low stability, low repeatability, low accuracy, poor portability, and so on. Critical discussion is provided on the trade-off relationship between detection speed and detection accuracy, as well as the application scenario and sustainability of different technologies. Especially, the prospect of combining different technologies is discussed. Future research is necessary to develop more convenient, more accurate, faster, and cost-effective technologies to detect aflatoxins.

Lipoxidation in cardiovascular diseases

Lipids can go through lipid peroxidation, an endogenous chain reaction that consists in the oxidative degradation of lipids leading to the generation of a wide variety of highly reactive carbonyl species (RCS), such as short-chain carbonyl derivatives and oxidized truncated phospholipids. RCS exert a wide range of biological effects due to their ability to interact and covalently bind to nucleophilic groups on other macromolecules, such as nucleic acids, phospholipids, and proteins, forming reversible and/or irreversible modifications and generating the so-called advanced lipoxidation end-products (ALEs). Lipoxidation plays a relevant role in the onset of cardiovascular diseases (CVD), mainly in the atherosclerosis-based diseases in which oxidized lipids and their adducts have been extensively characterized and associated with several processes responsible for the onset and development of atherosclerosis, such as endothelial dysfunction and inflammation. Herein we will review the current knowledge on the sources of lipids that undergo oxidation in the context of cardiovascular diseases, both from the bloodstream and tissues, and the methods for detection, characterization, and quantitation of their oxidative products and protein adducts. Moreover, lipoxidation and ALEs have been associated with many oxidative-based diseases, including CVD, not only as potential biomarkers but also as therapeutic targets. Indeed, several therapeutic strategies, acting at different levels of the ALEs cascade, have been proposed, essentially blocking ALEs formation, but also their catabolism or the resulting biological responses they induce. However, a deeper understanding of the mechanisms of formation and targets of ALEs could expand the available therapeutic strategies.

Influence of Diosmin Treatment on the Level of Oxidative Stress Markers in Patients with Chronic Venous Insufficiency

Oxidative stress plays an important role in the pathophysiology of many human disorders, while antioxidants prevent the development of various adverse symptoms. Diosmin is a natural flavonoid applied in vascular system disorders, especially in chronic venous insufficiency (CVI), and it plays a significant part in the alleviation of CVI symptoms. Due to antioxidant activity, it also has the ability to scavenge the oxygen free radicals and hence decreases the level of oxidative stress biomarkers, such as prostaglandins and their precursors—isoprostanes. In the study, the influence of diosmin treatment on the level of isoprostanes in plasma samples of patients suffering from CVI was examined. The qualitative analysis was performed using high-performance liquid chromatography with spectrometry detection (LC-MS). The statistically significant decrease of isoprostane content after 3 months of treatment was observed within the studied group; however, the most significant changes were observed in patients who smoke.

Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-Dependent Signaling in the Cardiovascular System: A Scientific Statement From the American Heart Association

Reactive oxygen species and reactive nitrogen species are biological molecules that play important roles in cardiovascular physiology and contribute to disease initiation, progression, and severity. Because of their ephemeral nature and rapid reactivity, these species are difficult to measure directly with high accuracy and precision. In this statement, we review current methods for measuring these species and the secondary products they generate and suggest approaches for measuring redox status, oxidative stress, and the production of individual reactive oxygen and nitrogen species. We discuss the strengths and limitations of different methods and the relative specificity and suitability of these methods for measuring the concentrations of reactive oxygen and reactive nitrogen species in cells, tissues, and biological fluids. We provide specific guidelines, through expert opinion, for choosing reliable and reproducible assays for different experimental and clinical situations. These guidelines are intended to help investigators and clinical researchers avoid experimental error and ensure high-quality measurements of these important biological species.

Simultaneous quantitative profiling of 20 isoprostanoids from omega-3 and omega-6 polyunsaturated fatty acids by LC-MS/MS in various biological samples

Isoprostanoids are a group of non-enzymatic oxygenated metabolites of polyunsaturated fatty acids. It belongs to oxylipins group, which are important lipid mediators in biological processes, such as tissue repair, blood clotting, blood vessel permeability, inflammation and immunity regulation. Recently, isoprostanoids from eicosapentaenoic, docosahexaenoic, adrenic and α-linolenic namely F3-isoprostanes, F4-neuroprostanes, F2-dihomo-isoprostanes and F1-phytoprostanes, respectively have attracted attention because of their putative contribution to health. Since isoprostanoids are derived from different substrate of PUFAs and can have similar or opposing biological consequences, a total isoprostanoids profile is essential to understand the overall effect in the testing model. However, the concentration of most isoprostanoids range from picogram to nanogram, therefore a sensitive method to quantify 20 isoprostanoids simultaneously was formulated and measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The lipid portion from various biological samples was extracted prior to LC-MS/MS evaluation. For all the isoprostanoids LOD and LOQ, and the method was validated on plasma samples for matrix effect, yield of extraction and reproducibility were determined. The methodology was further tested for the isoprostanoids profiles in brain and liver of LDLR(-/-) mice with and without docosahexaenoic acid (DHA) supplementation. Our analysis showed similar levels of total F2-isoprostanes and F4-neuroprostanes in the liver and brain of non-supplemented LDLR(-/-) mice. The distribution of different F2-isoprostane isomers varied between tissues but not for F4-neuroprostanes which were predominated by the 4(RS)-4-F4t-neuroprostane isomer. DHA supplementation to LDLR(-/-) mice concomitantly increased total F4-neuroprostanes levels compared to F2-isoprostanes but this effect was more pronounced in the liver than brain.