Oxidative Stress and Asprosin Levels in Type 2 Diabetic Patients with Good and Poor Glycemic Control.

Objectives: HbA1c is the most widely used test as an indicator of glucoregulation in patients with type 2 diabetes mellitus (T2DM). Asprosin and oxidative stress levels can be reduced with good glycemic control (GC) and thus prevented or delayed micro/macro complications in patients with T2DM. The relationship between asprosin, which is thought to affect GC, and oxidative stress parameters such as lipid hydroperoxides (LOOHs), glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (Cu,Zn-SOD), and total antioxidant capacity (TAC) was evaluated in T2DM patients. Materials and Methods: The study was conducted prospectively in 75 healthy people admitted to the hospital for a general health check-up and 150 T2DM patients treated in the diabetes outpatient clinic. The patient's glycemic status measurements were categorized as good glycemic control group (GGC) is defined as HbA1c < 7 and poor glycemic control (PGC) group is defined as HbA1c ≥ 7. Results: The study found a consistent increase in LOOH and MDA levels across the control, GGC, and PGC groups, while GSH, Cu/Zn-SOD, and TAC levels decreased in these respective groups. Additionally, asprosin levels showed a gradual rise in all groups. Positive correlations were observed between asprosin levels and various metabolic and oxidative stress markers, including BMI, WC, FBG, insulin, homeostasis model assessment for insulin resistance (HOMA-IR), DM duration, LOOH, and MDA, while negative correlations were noted with GSH, Cu/Zn-SOD, and TAC specifically in the PGC group. Furthermore, multivariate regression analysis identified HOMA-IR as the primary influencing factor on asprosin levels in PGC patients. Conclusions: Current glycemic dysregulation may lead to increased circulating asprosin and oxidative stress, which cause complications. Since asprosin levels may be an important hormonal factor in determining GC in T2DM, the use of this hormone may be recommended in the future to accelerate therapeutic approaches in T2DM. Early diagnosis and appropriate treatment may delay the development and progression of diabetic complications.

Emerging role of ferroptosis in metabolic dysfunction-associated steatotic liver disease: revisiting hepatic lipid peroxidation.

Metabolic dysfunction-associated steatohepatitis (MASH) is characterised by cell death of parenchymal liver cells which interact with their microenvironment to drive disease activity and liver fibrosis. The identification of the major death type could pave the way towards pharmacotherapy for MASH. To date, increasing evidence suggest a type of regulated cell death, named ferroptosis, which occurs through iron-catalysed peroxidation of polyunsaturated fatty acids (PUFA) in membrane phospholipids. Lipid peroxidation enjoys renewed interest in the light of ferroptosis, as druggable target in MASH. This review recapitulates the molecular mechanisms of ferroptosis in liver physiology, evidence for ferroptosis in human MASH and critically appraises the results of ferroptosis targeting in preclinical MASH models. Rewiring of redox, iron and PUFA metabolism in MASH creates a proferroptotic environment involved in MASH-related hepatocellular carcinoma (HCC) development. Ferroptosis induction might be a promising novel approach to eradicate HCC, while its inhibition might ameliorate MASH disease progression.

Inhibition of the skeletal muscle Lands cycle ameliorates weakness induced by physical inactivity.

BACKGROUND: Lipid hydroperoxides (LOOH) have been implicated in skeletal muscle atrophy with age and disuse. Lysophosphatidylcholine acyltransferase 3 (LPCAT3), an enzyme of the Lands cycle, conjugates a polyunsaturated fatty acyl chain to a lysophospholipid to form a polyunsaturated fatty acid containing phospholipid (PUFA-PL) molecule, providing substrates for LOOH propagation. Previous studies suggest that inhibition of the Lands cycle is an effective strategy to suppress LOOH. Mice with skeletal muscle-specific tamoxifen-inducible knockout of LPCAT3 (LPCAT3-MKO) were utilized to determine if muscle-specific attenuation of LOOH may alleviate muscle atrophy and weakness with disuse. METHODS: LPCAT3-MKO and control mice underwent 7 days of sham or hindlimb unloading (HU model) to study muscle mass and force-generating capacity. LOOH was assessed by quantifying 4-hydroxynonenal (4-HNE)-conjugated peptides. Quantitative PCR and lipid mass spectrometry were used to validate LPCAT3 deletion. RESULTS: Seven days of HU was sufficient to induce muscle atrophy and weakness concomitant to a ~2-fold increase in 4-HNE (P = 0.0069). Deletion of LPCAT3 reversed HU-induced increase in muscle 4-HNE (P = 0.0256). No difference was found in body mass, body composition, or caloric intake between genotypes. The soleus (SOL) and plantaris (PLANT) muscles of the LPCAT3-MKO mice experienced ~15% and ~40% less atrophy than controls, respectively. (P = 0.0011 and P = 0.0265). Type I and IIa SOL myofibers experienced a ~40% decrease in cross sectional area (CSA), which was attenuated to only 15% in the LPCAT3-MKO mice (P = 0.0170 and P = 0.0411, respectively). Strikingly, SOL muscles were fully protected and extensor digitorum longus (EDL) muscles experienced a ~35% protection from HU-induced reduction in force-generating capacity in the LPCAT3-MKO mice compared with controls (P < 0.0001 for both muscles). CONCLUSIONS: Our findings demonstrate that attenuation of skeletal muscle lipid hydroperoxides is sufficient to restore its function, in particular a protection from reduction in muscle specific force. Our findings suggest muscle lipid peroxidation contributes to atrophy and weakness induced by disuse in mice.

Inhibition of skeletal muscle Lands cycle ameliorates weakness induced by physical inactivity.

Background: Lipid hydroperoxides (LOOH) have been implicated in skeletal muscle atrophy with age and disuse. Lysophosphatidylcholine acyltransferase 3 (LPCAT3), an enzyme of Lands cycle, conjugates a polyunsaturated fatty acyl chain to a lysophospholipid (PUFA-PL) molecule, providing substrates for LOOH propagation. Previous studies suggest that inhibition of Lands cycle is an effective strategy to suppress LOOH. Mice with skeletal muscle-specific tamoxifen-inducible knockout of LPCAT3 (LPCAT3-MKO) were utilized to determine if muscle-specific attenuation of LOOH may alleviate muscle atrophy and weakness with disuse. Methods: LPCAT3-MKO and control mice underwent 7 days of sham or hindlimb unloading (HU model) to study muscle mass and force-generating capacity. LOOH was assessed by quantifying 4-hydroxynonenal (4-HNE)-conjugated peptides. Quantitative PCR and lipid mass spectrometry were used to validate LPCAT3 deletion. Results: 7 days of HU was sufficient to induce muscle atrophy and weakness concomitant to an increase in 4-HNE. Deletion of LPCAT3 reversed HU-induced increase in muscle 4HNE. No difference was found in body mass, body composition, or caloric intake between genotypes. The soleus (SOL) and plantaris (PLANT) muscles of the LPCAT3-MKO mice were partially protected from atrophy compared to controls, concomitant to attenuated decrease in cross-sectional areas in type I and IIa fibers. Strikingly, SOL and extensor digitorum longus (EDL) were robustly protected from HU-induced reduction in force-generating capacity in the LPCAT3-MKO mice compared to controls. Conclusion: Our findings demonstrate that attenuation of muscle LOOH is sufficient to restore skeletal muscle function, in particular a protection from reduction in muscle specific force. Thus, muscle LOOH contributes to atrophy and weakness induced by HU in mice.

Low-Field Benchtop NMR Spectroscopy for Quantification of Aldehydic Lipid Oxidation Products in Culinary Oils during Shallow Frying Episodes.

INTRODUCTION: Toxic aldehydic lipid oxidation products (LOPs) arise from the thermo-oxidative deterioration of unsaturated fatty acids present in heated culinary oils when exposed to high-temperature frying episodes, and currently these effects represent a major public health concern. OBJECTIVES: In this study, we investigated the applications of low-field (LF), benchtop NMR analysis to detect and quantify toxic aldehyde species in culinary oils following their exposure to laboratory-simulated shallow frying episodes (LSSFEs) at 180 °C. Four culinary oils of variable fatty acid (FA) composition were investigated to determine the analytical capabilities of the LF NMR instrument. Oil samples were also analysed using a medium-field (400 MHz) NMR facility for comparative purposes. RESULTS: Aldehydes were quantified as total saturated and total α,ß-unsaturated classes. The time-dependent production of α,ß-unsaturated aldehydes decreased in the order chia > rapeseed ≈ soybean > olive oils, as might be expected from their polyunsaturated and monounsaturated FA (PUFA and MUFA, respectively) contents. A similar but inequivalent trend was found for saturated aldehyde concentrations. These data strongly correlated with medium-field 1H NMR data obtained, although LF-determined levels were significantly lower in view of its inability to detect or quantify the more minor oxygenated aldehydic LOPs present. Lower limit of detection (LLOD) values for this spectrometer were 0.19 and 0.18 mmol/mol FA for n-hexanal and trans-2-octenal, respectively. Aldehydic lipid hydroperoxide precursors of aldehydic LOPs were also detectable in LF spectra. CONCLUSIONS: We therefore conclude that there is scope for application of these smaller, near-portable NMR facilities for commercial or 'on-site' quality control determination of toxic aldehydic LOPs in thermally stressed frying oils.

Review of Lipid Biomarkers and Signals of Photooxidative Stress in Plants.

The degree of unsaturation of plant lipids is high, making them sensitive to oxidation. They thus constitute primary targets of reactive oxygen species and oxidative stress. Moreover, the hydroperoxides generated during lipid peroxidation decompose in a variety of secondary products which can propagate oxidative stress or trigger signaling mechanisms. Both primary and secondary products of lipid oxidation are helpful markers of oxidative stress in plants. This chapter describes a number of methods that have been developed to measure those biomarkers and signals, with special emphasis on the monitoring of photooxidative stress. Depending on their characteristics, those lipid markers provide information not only on the oxidation status of plant tissues but also on the origin of lipid peroxidation, the localization of the damage, or the type of reactive oxygen species involved.

Unravelling the role of sodium chloride and hydroxytyrosol on the colloidal properties and oxidative stability of olive oil-based o/w emulsions: A multivariate statistical approach.

The individual and combined effect of sodium chloride and hydroxytyrosol on the colloidal properties and the chemical and physical stability of olive oil-in-water emulsions was explored by multivariate statistical analysis. Sodium chloride affected the dispersion degree of the emulsions causing an increase of droplet size and inducing flocculation phenomena; however, during storage, the presence of hydroxytyrosol, when added in combination with 2% and 5% of NaCl, retarded samples physical destabilization. A protective effect of salt on lipid hydroperoxides, over storage, was highlighted, mainly at the highest concentrations used. The analysis of volatile organic compounds allowed to identify different oxidation patterns as a consequence of NaCl addition and hydroxytyrosol; moreover, by applying a multivariate statistical approach, it was possible to highlight a positive effect of both NaCl and hydroxytyrosol over the reduction of some oxidation volatiles.

Redox status biomarkers in the fast-twitch extensor digitorum longus resulting from the hypoxic exercise.

The fast-twitch muscle may be affected from over-produced reactive oxygen species (ROS) during hypoxia/hypoxic exercise. The study aims to investigate redox status biomarkers in the fast-twitch extensor digitorum longus (EDL) muscle after hypoxic exercise. Male Sprague Dawley rats (eight-week-old) were randomly divided into six groups of the experimental "live high train high (LHTH), live high train low (LHTL) and live low train low (LLTL)" and their respective controls. Before the EDLs' extraction, the animals exercised for a 4-week familiarization period, then they exercised for four-weeks at different altitudes. The LHTH group had higher ratios of lipid hydroperoxides (LHPs) than the experimental groups of LHTL (p=0.004) and LLTL (p=0.002), while having no difference than its control 'LH'. Similarly, a higher percentage of advanced oxidation protein products (AOPP) was determined in the LHTH than the LHTL (p=0.041) and LLTL (p=0.048). Furthermore, oxidation of thiol fractions was the lowest in the LHTH and LH. However, redox biomarkers and thiol fractions illustrated no significant change in the LHTL and LLTL that might ensure redox homeostasis due to higher oxygen consumption. The study shows that not hypoxic exercise/exercise, but hypoxia might itself lead to a redox imbalance in the fast-twitch EDL muscle.

Oxidative Stress and Lipid Dysregulation in Lipid Droplets: A Connection to Chronic Kidney Disease Revealed in Human Kidney Cells.

Chronic kidney disease (CKD), which is defined as a condition causing the gradual loss of kidney function, shows renal lipid droplet (LD) accumulation that is associated with oxidative damage. There is a possibility that an LD abnormality in quality plays a role in CKD development. This study aimed to explore the chemical composition of LDs that are induced in human kidney cells during exposure to free fatty acids as an LD source and oxidized lipoproteins as oxidative stress. The LDs were aspirated directly from cells using nanotips, followed by in-tip microextraction, and the LD lipidomic profiling was conducted using nanoelectrospray mass spectrometry. As a result, the free fatty acids increased the LD lipid content and, at the same time, changed their composition significantly. The oxidized lipoproteins caused distorted proportions of intact lipids, such as triacylglycerols (TG), phosphatidylcholines (PC), phosphatidylethanolamines (PE), and cholesteryl esters (CE). Notably, the oxidized lipids, including the hydroperoxides of TG, PC, and PE, exhibited significant elevations in dose-dependent manners. Furthermore, the dysregulation of intact lipids was paralleled with the accumulation of lipid hydroperoxides. The present study has revealed that the oxidation of lipids and the dysregulation of the lipid metabolism coexisted in LDs in the kidney cells, which has provided a potential new target for diagnosis and new insights into CKD.

Genetic Disruption of the γ-Glutamylcysteine Ligase in PDAC Cells Induces Ferroptosis-Independent Cell Death In Vitro without Affecting In Vivo Tumor Growth.

The conceptualization of a novel type of cell death, called ferroptosis, opens new avenues for the development of more efficient anti-cancer therapeutics. In this context, a full understanding of the ferroptotic pathways, the players involved, their precise role, and dispensability is prerequisite. Here, we focused on the importance of glutathione (GSH) for ferroptosis prevention in pancreatic ductal adenocarcinoma (PDAC) cells. We genetically deleted a unique, rate-limiting enzyme for GSH biosynthesis, γ-glutamylcysteine ligase (GCL), which plays a key role in tumor cell proliferation and survival. Surprisingly, although glutathione peroxidase 4 (GPx4) has been described as a guardian of ferroptosis, depletion of its substrate (GSH) led preferentially to apoptotic cell death, while classical ferroptotic markers (lipid hydroperoxides) have not been observed. Furthermore, the sensitivity of PDAC cells to the pharmacological/genetic inhibition of GPx4 revealed GSH dispensability in this context. To the best of our knowledge, this is the first time that the complete dissection of the xCT-GSH-GPx4 axis in PDAC cells has been investigated in great detail. Collectively, our results revealed the necessary role of GSH in the overall redox homeostasis of PDAC cells, as well as the dispensability of this redox-active molecule for a specific, antioxidant branch dedicated to ferroptosis prevention.

Vitamin E protects from lipid peroxidation during winter stress in the seagrass Cymodocea nodosa.

MAIN CONCLUSION: Adjustments in the antenna size and α-tocopherol contents provide protection from sustained damage in leaves of a seagrass, while low vitamin E contents appear to be enough to protect rhizomes (which appear to be more cold tolerant than leaves). Despite low temperatures can adversely affect the proper growth and development of marine angiosperms, by, among other processes, increasing reactive oxygen species production and causing oxidative damage to lipid membranes, the role of vitamin E in seagrasses, such as Cymodocea nodosa has not been explored thus far. Here, we aimed to better understand the possible role of this chain-breaking (peroxyl radical-trapping) antioxidant in response to low temperatures, and most particularly in relation to the occurrence of photo-inhibition and lipid peroxidation. Low temperatures caused an important desiccation of leaves, but not of rhizomes, which were much more tolerant to cold stress than leaves. Cold stress during winter was associated with chlorophyll loss and transient photo-inhibition, as indicated by reversible reductions in the Fv/Fm ratio. Adjustments in pigment antenna size and vitamin E contents per unit of chlorophyll during winter may help protect the photosynthetic apparatus from sustained photo-inhibitory damage and lipid peroxidation events in leaves. Rhizomes also accumulated significant amounts of vitamin E, although to a much lesser extent than leaves, and kept protected from lipid peroxidation during winter, as indicated by malondialdehyde contents, a product from secondary lipid peroxidation. It is concluded that vitamin E can help protect both leaves and rhizomes from lipid peroxidation, although cold stress during winter can cause transient photo-inhibition of the photosynthetic apparatus, in C. nodosa.

New insights into the kinetic and thermodynamic evaluations of lipid peroxidation.

Simultaneous evaluations over the whole practical range of peroxidation, including the initiation and propagation phases, provide more informative and reliable data than single-parameter analyses being mostly employed only over the course of the initiation phase. Besides an overview on the dominant mechanisms governing the initiation and propagation phases, this article highlights a number of unifying parameters that represent inclusively the two phases. Then, the reliable method to calculate induction period and critical reverse micelle concentration of lipid hydroperoxides as the two interstitial parameters when transitioning from the initiation to the propagation phase is reviewed. Next, a reconsidered form of the conventional methodology on the kinetics of chain-breaking antioxidants is presented. After that, the Arrhenius kinetic and thermodynamic Eyring-Polanyi parameters calculated from the initiation, composite, and decomposition rate constants are compared in order to assess oxidative stabilities. Finally, shelf-life predictions based on a number of proposed end-points of peroxidation are addressed.

Oxidative Stress Linked Organ Lipid Hydroperoxidation and Dysregulation in Mouse Model of Nonalcoholic Steatohepatitis: Revealed by Lipidomic Profiling of Liver and Kidney.

Nonalcoholic steatohepatitis (NASH) is a prevalent disease related to lipid metabolism disorder and oxidative stress. Lipid hydroperoxidation is known to be a critical driving force of various disorders and diseases. However, the combination of both intact and hydroperoxidized lipids in NASH has not yet been studied. In this work, the liver and kidney samples from NASH-model mice were comprehensively investigated by using the LC/MS-based lipidomic analysis. As a result, triglycerides showed the amount accumulation and the profile alteration for the intact lipids in the NASH group, while phosphatidylethanolamines, lysophosphatidylethanolamines, plasmalogens, and cardiolipins largely depleted, suggesting biomembrane damage and mitochondria dysfunction. Notably, the lipid hydroperoxide species of triglyceride and phosphatidylcholine exhibited a significant elevation in both the liver and the kidney of the NASH group and showed considerable diagnostic ability. Furthermore, the relationship was revealed between the lipid metabolism disturbance and the lipid hydroperoxide accumulation, which played a key role in the vicious circle of NASH. The present study suggested that the omics approach to the lipid hydroperoxide profile might be the potential diagnostic marker of NASH and other oxidative stress-related diseases, as well as the evaluative treatment index of antioxidants.

Structural Analysis of Lipid Hydroperoxides Using Mass Spectrometry with Alkali Metals.

Lipid oxidation is involved in various biological phenomena (e.g., oxylipin generation and oxidative stress). Of oxidized lipid structures, the hydroperoxyl group position of lipid hydroperoxides (LOOHs) is a critical factor in determining their biological roles. Despite such interest, current methods to determine hydroperoxyl group positions possess some drawbacks such as selectivity. While we previously reported mass spectrometric methods using Na+ for the highly selective determination of hydroperoxyl group positions, nothing was known except for the fact that sodiated LOOHs (mainly linoleate) provide specific fragment ions. Thus, this study was aimed to investigate the effects of different alkali metals on the fragmentation of LOOHs, assuming its further application to analysis of other complex LOOHs. From the analysis of PC 16:0/18:2;OOH (phosphatidylcholine) and FA 18:2;OOH (fatty acid), we found that fragmentation pathways and ion intensities largely depend on the binding position and type of alkali metals (i.e., Li+, Hock fragmentation; Na+ and K+, α-cleavage (Na+ > K+); Rb+ and Cs+, no fragmentation). Furthermore, we proved that this method can be applied to determine the hydroperoxyl group position of esterified lipids (e.g., phospholipids and cholesterol esters) as well as polyunsaturated fatty acids (PUFAs) including n-3, n-6, and n-9 FA. We anticipate that the insights described in this study provide additional unique insights to conventional lipid oxidation research.

Lipid hydroperoxides in nutrition, health, and diseases.

Research on lipid peroxidation in food degradation, oil and fat nutrition, and age-related diseases has gained significant international attention for the view of improvement of societal health and longevity. In order to promote basic studies on these topics, a chemiluminescence detection-high performance liquid chromatography instrument using a high-sensitivity single photon counter as a detector was developed. This instrument enabled us to selectively detect and quantify lipid hydroperoxides, a primary product of lipid peroxidation reactions, as hydroperoxide groups at the lipid class level. Furthermore, an analytical method using liquid chromatography-tandem mass spectrometry has been established to discriminate the position and stereoisomerization of hydroperoxide groups in lipid hydroperoxides. Using these two methods, the reaction mechanisms of lipid peroxidation in food and in the body have been confirmed.

Recommendations for the use of the acetaminophen hepatotoxicity model for mechanistic studies and how to avoid common pitfalls.

Acetaminophen (APAP) is a widely used analgesic and antipyretic drug, which is safe at therapeutic doses but can cause severe liver injury and even liver failure after overdoses. The mouse model of APAP hepatotoxicity recapitulates closely the human pathophysiology. As a result, this clinically relevant model is frequently used to study mechanisms of drug-induced liver injury and even more so to test potential therapeutic interventions. However, the complexity of the model requires a thorough understanding of the pathophysiology to obtain valid results and mechanistic information that is translatable to the clinic. However, many studies using this model are flawed, which jeopardizes the scientific and clinical relevance. The purpose of this review is to provide a framework of the model where mechanistically sound and clinically relevant data can be obtained. The discussion provides insight into the injury mechanisms and how to study it including the critical roles of drug metabolism, mitochondrial dysfunction, necrotic cell death, autophagy and the sterile inflammatory response. In addition, the most frequently made mistakes when using this model are discussed. Thus, considering these recommendations when studying APAP hepatotoxicity will facilitate the discovery of more clinically relevant interventions.

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.

Aqueous leaf extract from Luehea divaricata Mart. Modulates oxidative stress markers in the spinal cord of rats with neuropathic pain.

ETHNOPHARMACOLOGICAL RELEVANCE: Reactive oxygen species (ROS) play an important role in neuropathic pain (i.e., pain caused by lesion or disease of the somatosensory system). We showed previously that the aqueous extract prepared from Luehea divaricata leaves, a plant explored by native ethnic groups of Brazil to treat different pathologic conditions, exhibits good antioxidant activity and induces analgesia in rats with neuropathic pain (J Ethnopharmacol, 2020; 256:112761. doi: 10.1016/j.jep.2020.112761). The effect was comparable to that of gabapentin, a drug recommended as first-line treatment for neuropathic pain. However, increasing evidence has indicated the need to accurately determine the oxidative stress level of an individual before prescribing supplemental antioxidants. AIM OF THE STUDY: This study assessed the effects of the oral administration of aqueous extract from leaves of L. divaricata on the sciatic functional index (SFI) and spinal-cord pro-oxidant and antioxidant markers of rats with neuropathic pain. MATERIALS AND METHODS: Placement of four loose chromic thread ligatures around the sciatic nerve produced chronic constriction injury (CCI) of the sciatic nerve, a commonly employed animal model to study neuropathic pain. Aqueous extract from leaves of L. divaricata (100, 300, 500 and 1000 mg/kg), gabapentin (50 mg/kg) and aqueous extract (500 mg/kg) + gabapentin (30 mg/kg) were administrated per gavage daily for 10 or 35 days post-CCI. Antinociception was assessed using the von Frey test while SFI showed functional recovery post-nerve lesion throughout the experimental period. At days 10 and 35 post-surgery, the lumbosacral spinal cord and a segment of the injured sciatic nerve were dissected out and used to determine lipid hydroperoxide levels and total antioxidant capacity (TAC). The spinal cord was also used to determine superoxide anion generation (SAG), hydrogen peroxide (H2O2) levels and total thiol content. RESULTS: As expected, the extract, gabapentin and extract + gabapentin induced antinociception in CCI rats. While no significant functional recovery was found at 10 days post-CCI, a significant recovery was found in SFI of extract-treated CCI rats at 21 and 35 days post-CCI. A significant functional recovery was found already at day 10 post-CCI in gabapentin and gabapentin + extract-treated CCI rats. The extract treatment prevented increases in lipid hydroperoxides levels and TAC in injured sciatic nerve, which were found in this tissue of vehicle-treated rats at 10 days post-CCI. Extract also prevented an increase in SAG, H2O2 and lipid hydroperoxides levels in the spinal cord, which were elevated in this tissue of vehicle-treated rats at 10 and 35 days post-CCI. Extract also prevented a decrease in total thiol content and an increase in TAC in the spinal cord of CCI rats in these same time periods. CONCLUSIONS: Aqueous extract from L. divaricata leaves was demonstrated, for the first time, to improve SFI and modulate oxidative stress markers in injured sciatic nerve and spinal cord of CCI rats. Thus, the antinociceptive effect of the extract involves modulation of oxidative stress markers in injured sciatic nerve and spinal cord.

Influence of linseed and antioxidant-rich diets in pig nutrition on lipid oxidation during cooking and in vitro digestion of pork.

Enrichment of pig diets with polyunsaturated fatty acids (PUFA) is considered an emerging strategy to increase their intake in the human diet. However, PUFA are particularly vulnerable to oxidative reactions leading to the generation of toxic compounds. The aim of this study was to evaluate the effect of supplementation of pig diets with extruded linseed (L), either or not in combination with synthetic antioxidants (E, tocopheryl-acetate and selenium) or natural extracts (P, grape-skin and oregano), and basal diet (C, without linseed) on the oxidative stability in raw, grilled and in vitro digested pork. The diet supplementation with antioxidant-rich ingredients resulted in the accumulation of specific metabolites in meat. Actually, 11 different phenolic- and 6 tocopherol-derived metabolites were identified by UHPLC/HR-MS. These metabolites were potentially correlated with the reduction in the oxidative phenomena occurring during meat cooking and digestion. Specifically, 16% and 35% reduction in the amounts of lipid hydroperoxides and TBA-RS were assessed after cooking of meat from P diet, respect to the L diet. Diet supplementations with α-tocopheryl acetate and selenium reduced the oxidative reactions only during meat cooking. A significant reduction was attended at the end of in vitro digestion, showing about 24% and 34% hydroperoxides and TBA-RS concentration reductions, respectively, in P diet samples respect to the L ones. Thus, our study suggests that the appearance of phenolic metabolites in meat could be associated to a reduction in the oxidative phenomena during meat cooking and digestion.

Comprehensive lipidomic profiling in serum and multiple tissues from a mouse model of diabetes.

INTRODUCTION: Diabetes mellitus is a serious metabolic disorder causing multiple organ damage in human. However, the lipidomic profiles in different organs and their associations are rarely studied in either diabetic patients or animals. OBJECTIVES: To evaluate and compare the characteristics of lipid species in serum and multiple tissues in a diabetic mouse model. METHODS: Semi-quantitative profiling analyses of intact and oxidized lipids were performed in serum and multiple tissues from a diabetic mouse model fed a high fat diet and treated with streptozotocin by using LC/HRMS and MS/MS. The total content of each lipid class, and the tissue-specific lipid species in all tissue samples were determined and compared by multivariate analyses. RESULTS: The diabetic mouse model displayed characteristic differences in serum and multiple organs: the brain and heart showed the largest reduction in cardiolipin, while the kidney had more alterations in triacylglycerol. Interestingly, the lipidomic differences also existed between different regions of the same organ: cardiolipin species with highly polyunsaturated fatty acyls decreased only in atrium but not in ventricle, while renal cortex showed longer fatty acyl chains for both increased and decreased triacylglycerol species than renal medulla. Importantly, diabetes caused an accumulation of lipid hydroperoxides, suggesting that oxidative stress was induced in all organs except for the brain during the development of diabetes. CONCLUSIONS: These findings provided novel insight into the organ-specific relationship between diabetes and lipid metabolism, which might be useful for evaluating not only diabetic tissue injury but also the effectiveness of diabetic treatments.