F2-dihomo-isoprostanes arise from free radical attack on adrenic acid

Immunosuppressive therapies attenuate paraquat-induced renal dysfunction by suppressing inflammatory responses and lipid peroxidation

Although paraquat (PQ) induces oxidative damage and inflammatory responses in the lungs, the mechanism underlying PQ-induced acute kidney injury in patients is unclear. Immunosuppressive therapy with glucocorticoids and the immunosuppressant cyclophosphamide (CP) has been employed to treat patients with PQ poisoning. This study examined whether PQ could concurrently cause renal injury, inflammatory responses, and oxidative damage in the kidneys, and whether CP and dexamethasone (DEX) could suppress PQ-induced alterations. Mice were assigned to eight groups: Control, PQ, DEX, PQ plus DEX, CP, PQ plus CP, DEX plus CP, and PQ plus DEX with CP. DEX, CP, and DEX plus CP reversed PQ-induced renal injury, as indicated by urinary albumin-to-creatinine ratios and urea nitrogen levels in serum. The treatments also attenuated PQ-induced renal infiltration of leukocytes and macrophages and induction of the Il6, Tnf, Icam, Cxcl2, Tlr4, and Tlr9 genes encoding the inflammatory mediators in the kidneys. However, DEX only partially suppressed the macrophage infiltration, whereas DEX plus CP provided stronger protection than DEX or CP alone for the induction of Il6 and Cxcl2. Moreover, through the detection of F₂-isoprostanes (F₂-IsoPs) and isofurans in the kidneys and lungs and F₂-IsoPs in the plasma and urine, the therapies were found to suppress PQ-induced lipid peroxidation, although DEX was less effective. Finally, PQ decreased ubiquinol-9:ubiquinone-9 ratios in the kidneys. This effect of PQ was not found under CP treatment, but the ratio was lower than that of the control group. Our findings suggest that the suppression of PQ-induced inflammatory responses by DEX and CP in the kidneys can mitigate oxidative damage and acute kidney injury.

Assessment of Lipid Peroxidation in Alzheimer's Disease Differential Diagnosis and Prognosis

Alzheimer’s disease (AD) and other dementias are becoming increasingly common in the older population, and the number of people affected is expected to increase in a few years. Nowadays, biomarkers used in early AD diagnosis are expensive and invasive. Therefore, this research field is growing. In fact, peroxidation by-products derived from the oxidation of brain lipids (arachidonic (AA), docosahexanoic (DHA) and adrenic acid (AdA)) could be potential biomarkers, participating in the mechanisms of inflammation, neurotoxicity and cell death in AD pathology. Previous studies have shown specificity between lipid peroxidation compounds and other dementias (e.g., Lewy bodies (DLB), frontotemporal dementia (FTD)), but more research is required. Lipid peroxidation compounds (prostaglandins, isoprostanes, isofurans, neuroprostanes, neurofurans, dihomo-isoprostanes and dihomo-isofurans) were analysed by liquid chromatography and mass spectrometry in plasma samples from participants classified into a healthy group (n = 80), a mild cognitive impairment due to AD group (n = 106), a mild dementia due to AD group (n = 70), an advanced dementia due to AD group (n = 11) and a group of other non-AD dementias (n = 20). Most of these compounds showed statistically significant differences between groups (p < 0.05), showing higher levels for the healthy and non-AD groups than the AD groups. Then, a multivariate analysis was carried out on these compounds, showing good diagnosis indexes (AUC 0.77, sensitivity 81.3%, positive predictive value 81%). Moreover, evaluating AD disease prognosis, two compounds (15-F2t-IsoP and 14(RS)-14-F4t-NeuroP) and three total parameters (isoprostanes, isofurans and neurofurans) showed significant differences among groups. Some compounds derived from the oxidation of AA, DHA and AdA have demonstrated their potential use in differential AD diagnosis. Specifically, 15-F2t-IsoP, 14(RS)-14-F4t-NeuroP and the total parameters for isoprostanes, isofurans and neurofurans have shown prognostic value for AD from its earliest stages to its most severe form.

Isoprostanoid Plasma Levels Are Relevant to Cerebral Adrenoleukodystrophy Disease

Cerebral adrenoleukodystrophy (ALD) is a rare neuroinflammatory disorder characterized by progressive demyelination. Mutations within the ABCD1 gene result in very long-chain fatty acid (VLCFA) accumulation within the peroxisome, particularly in the brain. While this VLCFA accumulation is known to be the driving cause of the disease, oxidative stress can be a contributing factor. For patients with early cerebral disease, allogeneic hematopoietic stem cell transplantation (HSCT) is the standard of care, and this can be supported by antioxidants. To evaluate the involvement of fatty acid oxidation in the disease, F2-isoprostanes (F2-IsoPs), F2-dihomo-isoprostanes (F2-dihomo-IsoPs) and F4-neuroprostanes (F4-NeuroPs)-which are oxygenated metabolites of arachidonic (ARA), adrenic (AdA) and docosahexaenoic (DHA) acids, respectively-in plasma samples from ALD subjects (n = 20)-with various phenotypes of the disease-were measured. Three ALD groups were classified according to patients with: (1) confirmed diagnosis of ALD but without cerebral disease; (2) cerebral disease in early period post-HSCT (<100 days post-HSCT) and on intravenous N-acetyl-L-cysteine (NAC) treatment; (3) cerebral disease in late period post-HSCT (beyond 100 days post-HSCT) and off NAC therapy. In our observation, when compared to healthy subjects (n = 29), in ALD (i), F2-IsoPs levels were significantly (p < 0.01) increased in all patients, with the single exception of the early ALD and on NAC subjects; (ii) significant elevated (p < 0.0001) amounts of F2-dihomo-IsoPs were detected, with the exception of patients with a lack of cerebral disease; (iii), a significant increase (p < 0.003) in F4-NeuroP plasma levels was detected in all ALD patients. Moreover, F2-IsoPs plasma levels were significantly higher (p = 0.038) in early ALD in comparison to late ALD stage, and F4-NeuroPs were significantly lower (p = 0.012) in ALD subjects with a lack of cerebral disease in comparison to the late disease stage. Remarkably, plasma amounts of all investigated isoprostanoids were shown to discriminate ALD patients vs. healthy subjects. Altogether, isoprostanoids are relevant to the phenotype of X-ALD and may be helpful in predicting the presence of cerebral disease and establishing the risk of progression.

High Oxygen Does Not Increase Reperfusion Injury Assessed with Lipid Peroxidation Biomarkers after Cardiac Arrest: A Post Hoc Analysis of the COMACARE Trial

The products of polyunsaturated fatty acid peroxidation are considered reliable biomarkers of oxidative injury in vivo. We investigated ischemia-reperfusion-related oxidative injury by determining the levels of lipid peroxidation biomarkers (isoprostane, isofuran, neuroprostane, and neurofuran) after cardiac arrest and tested the associations between the biomarkers and different arterial oxygen tensions (PaO₂). We utilized blood samples collected during the COMACARE trial (NCT02698917). In the trial, 123 patients resuscitated from out-of-hospital cardiac arrest were treated with a 10–15 kPa or 20–25 kPa PaO₂ target during the initial 36 h in the intensive care unit. We measured the biomarker levels at admission, and 24, 48, and 72 h thereafter. We compared biomarker levels in the intervention groups and in groups that differed in oxygen exposure prior to randomization. Blood samples for biomarker determination were available for 112 patients. All four biomarker levels peaked at 24 h; the increase appeared greater in younger patients and in patients without bystander-initiated life support. No association between the lipid peroxidation biomarkers and oxygen exposure either before or after randomization was found. Increases in the biomarker levels during the first 24 h in intensive care suggest continuing oxidative stress, but the clinical relevance of this remains unresolved.

Moving forward with isoprostanes, neuroprostanes and phytoprostanes: where are we now?

Polyunsaturated fatty acids (PUFAs) are essential components in eukaryotic cell membrane. They take part in the regulation of cell signalling pathways and act as precursors in inflammatory metabolism. Beside these, PUFAs auto-oxidize through free radical initiated mechanism and release key products that have various physiological functions. These products surfaced in the early nineties and were classified as prostaglandin isomers or isoprostanes, neuroprostanes and phytoprostanes. Although these molecules are considered robust biomarkers of oxidative damage in diseases, they also contain biological activities in humans. Conceptual progress in the last 3 years has added more understanding about the importance of these molecules in different fields. In this chapter, a brief overview of the past 30 years and the recent scope of these molecules, including their biological activities, biosynthetic pathways and analytical approaches are discussed.

Analysis of Lipid Peroxidation by UPLC-MS/MS and Retinoprotective Effects of the Natural Polyphenol Pterostilbene

The loss of redox homeostasis induced by hyperglycemia is an early sign and key factor in the development of diabetic retinopathy. Due to the high level of long-chain polyunsaturated fatty acids, diabetic retina is highly susceptible to lipid peroxidation, source of pathophysiological alterations in diabetic retinopathy. Previous studies have shown that pterostilbene, a natural antioxidant polyphenol, is an effective therapy against diabetic retinopathy development, although its protective effects on lipid peroxidation are not well known. Plasma, urine and retinas from diabetic rabbits, control and diabetic rabbits treated daily with pterostilbene were analyzed. Lipid peroxidation was evaluated through the determination of derivatives from arachidonic, adrenic and docosahexaenoic acids by ultra-performance liquid chromatography coupled with tandem mass spectrometry. Diabetes increased lipid peroxidation in retina, plasma and urine samples and pterostilbene treatment restored control values, showing its ability to prevent early and main alterations in the development of diabetic retinopathy. Through our study, we are able to propose the use of a derivative of adrenic acid, 17(RS)-10-epi-SC-Δ¹⁵-11-dihomo-IsoF, for the first time, as a suitable biomarker of diabetic retinopathy in plasmas or urine.

Isoprostanes in Veterinary Medicine: Beyond a Biomarker

Oxidative stress has been associated with many pathologies, in both human and animal medicine. Damage to tissue components such as lipids is a defining feature of oxidative stress and can lead to the generation of many oxidized products, including isoprostanes (IsoP). First recognized in the early 1990s, IsoP are formed in numerous biological fluids and tissues, chemically stable, and easily measured by noninvasive means. Additionally, IsoP are highly specific indicators of lipid peroxidation and thereby are regarded as excellent biomarkers of oxidative stress. Although there have been many advancements in the detection and use of IsoP as a biomarker, there is still a paucity of knowledge regarding the biological activity of these molecules and their potential roles in pathology of oxidative stress. Furthermore, the use of IsoP has been limited in veterinary species thus far and represents an avenue of opportunity for clinical applications in veterinary practice. Examples of clinical applications of IsoP in veterinary medicine include use as a novel biomarker to guide treatment recommendations or as a target to mitigate inflammatory processes. This review will discuss the history, biosynthesis, measurement, use as a biomarker, and biological action of IsoP, particularly in the context of veterinary medicine.

New insight into the negative impact of imidazolium-based ionic liquid [C10mim]Cl on Hela cells: From membrane damage to biochemical alterations

As an alternative to volatile organic solvents, ionic liquids (ILs) are known as "green solvents", and widely used in industrial applications. However, due to their high solubility and stability, ILs have tendency to persist in the water environment, thus having potential negative impacts on the aquatic ecosystem. For assessing the environmental risks of ILs, a fundamental understanding of the toxic effects and mechanisms of ILs is needed. Here we evaluated the cytotoxicity of 1-methyl-3-decylimidazolium chloride ([C₁₀mim]Cl) and elucidated the main toxic mechanism of [C₁₀mim]Cl in human cervical carcinoma (Hela) cells. Microstructural analysis revealed that [C₁₀mim]Cl exposure caused the cell membrane breakage, swollen and vacuolated mitochondria, and spherical cytoskeletal structure. Cytotoxicity assays found that [C₁₀mim]Cl exposure increased ROS production, decreased mitochondrial membrane potential, induced cell apoptosis and cell cycle arrest. These results indicated that [C₁₀mim]Cl could induce damage to cellular membrane structure, affect the integrity of cell ultrastructure, cause the oxidative damage and ultimately lead to the inhibition of cell proliferation. Moreover, alterations of biochemical information including the increased ratios of unsaturated fatty acid and carbonyl groups to lipid, and lipid to protein, and the decreased ratios of Amide I to Amide II, and α-helix to β-sheet were observed in [C₁₀mim]Cl treated cells, suggesting that [C₁₀mim]Cl could affect the structure of membrane lipid alkyl chain and cell membrane fluidity, promote the lipid peroxidation and alter the protein secondary structure. The findings from this work demonstrated that membrane structure is the key target, and membrane damage is involved in [C₁₀mim]Cl induced cytotoxicity.

Extended lipid profile in Romanian ischemic stroke patients in relation to stroke severity and outcome: a path analysis model

INTRODUCTION

Our aim was to evaluate the extended lipid profile in ischemic stroke patients and the relationship with stroke type, severity and outcome.

MATERIAL AND METHODS

We prospectively enrolled 124 ischemic stroke patients and 40 healthy controls; baseline plasma and erythrocyte membrane fatty acids concentrations and common lipid profile were analysed. Stroke severity was evaluated by NIHSS on admission, while the functional outcome was defined by mRS at discharge and after 3 months.

RESULTS

Total cholesterol, triglycerides, HDL-cholesterol, DHA, adrenic, stearic and lauric acid were all lower in patients, taking into account that 87.7% of patients did not receive statins before admission. There was a different pattern in plasma and erythrocyte membrane of fatty acids between patients and controls, also omega-3 index was significantly lower in patients. Patients with poor outcome without statins had significantly lower triglyceride (p = 0.028), while the total cholesterol levels were significantly lower in patients with poor outcome (p = 0.03) but with treatment initiated after admission. Bivariate analysis revealed that patients with poor outcome had significantly lower triglyceride levels regardless the statins use, while the total cholesterol and HDL-cholesterol levels were significantly lower in patients with poor outcome under statin treatment. The long-term outcome were positively influenced by age (β̂ = 0.22, p = 0.001), and NIHSS score at admission (β̂ = 0.55, p < 0.001), and negatively by cholesterol levels (β̂ = -0.17, p = 0.031).

CONCLUSIONS

DHA, adrenic, stearic and lauric acid were lower in stroke patients; plasma adrenic acid was consumed during the acute phase. The most important predictors for long-term outcome was NIHSS at admission followed by age and total cholesterol.

First Total Syntheses of Novel Non-Enzymatic Polyunsaturated Fatty Acid Metabolites and Their Identification in Edible Oils

Oxidative stress (OS) is an in vivo process leading to free radical overproduction, which triggers polyunsaturated fatty acid (PUFA) peroxidation resulting in the formation of racemic non-enzymatic oxygenated metabolites. As potential biomarkers of OS, their in vivo quantification is of great interest. However, since a large number of isomeric metabolites is formed in parallel, their quantification remains difficult without primary standards. Three new PUFA-metabolites, namely 18-F_3t -isoprostane (IsoP) from eicosapentaenoic acid (EPA), 20-F_4t -neuroprostane (NeuroP) from docosahexaenoic acid (DHA) and 20-F_3t -NeuroP from docosapentaenoic acid (DPA_n-3 ) were synthesized by two complementary synthetic strategies. The first one relied on a racemic approach to 18(RS)-18-F_3t -IsoP using an oxidative radical anion cyclization as a key step, whereas the second used an enzymatic deracemization of a bicyclo[3.3.0]octene intermediate obtained from cyclooctadiene to pursue an asymmetric synthesis. The synthesized metabolites were applied in targeted lipidomics to prove lipid peroxidation in edible oils of commercial nutraceuticals.

Increase in omega-6 and decrease in omega-3 polyunsaturated fatty acid oxidation elevates the risk of exudative AMD development in adults with Chinese diet

Appropriate diet is essential for the regulation of age-related macular degeneration (AMD). In particular the type of dietary polyunsaturated fatty acids (PUFA) and poor antioxidant status including carotenoid levels concomitantly contribute to AMD risk. Build-up of oxidative stress in AMD induces PUFA oxidation, and a mix of lipid oxidation products (LOPs) are generated. However, LOPs are not comprehensively evaluated in AMD. LOPs are considered biomarkers of oxidative stress but also contributes to inflammatory response. In this cross-sectional case-control study, plasma omega-6/omega-3 PUFA ratios and antioxidant status (glutathione, superoxide dismutase and catalase), and plasma and urinary LOPs (41 types) were determined to evaluate its odds-ratio in the risk of developing exudative AMD (n = 99) compared to age-gender-matched healthy controls (n = 198) in adults with Chinese diet. The odds ratio of developing exudative AMD increased with LOPs from omega-6 PUFA and decreased from those of omega-3 PUFA. These observations were associated with a high plasma omega-6/omega-3 PUFA ratio and low carotenoid levels. In short, poor PUFA and antioxidant status increased the production of omega-6 PUFA LOPs such as dihomo-isoprostane and dihomo-isofuran, and lowered omega-3 PUFA LOPs such as neuroprostanes due to the high omega-6/omega-3 PUFA ratios; they were also correlated to the risk of AMD development. These findings indicate the generation of specific LOPs is associated with the development of exudative AMD.

Recent development on liquid chromatography-mass spectrometry analysis of oxidized lipids

Polyunsaturated fatty acids (PUFAs) in the cellular membrane can be oxidized by various enzymes or reactive oxygen species (ROS) to form many oxidized lipids. These metabolites are highly bioactive, participating in a variety of physiological and pathophysiological processes. Mass spectrometry (MS), coupled with Liquid Chromatography, has been increasingly recognized as an indispensable tool for the analysis of oxidized lipids due to its excellent sensitivity and selectivity. We will give an update on the understanding of the molecular mechanisms related to generation of various oxidized lipids and recent progress on the development of LC-MS in the detection of these bioactive lipids derived from fatty acids, cholesterol esters, and phospholipids. The purpose of this review is to provide an overview of the formation mechanisms and technological advances in LC-MS for the study of oxidized lipids in human diseases, and to shed new light on the potential of using oxidized lipids as biomarkers and mechanistic clues of pathogenesis related to lipid metabolism. The key technical problems associated with analysis of oxidized lipids and challenges in the field will also discussed.

Adrenic acid non-enzymatic peroxidation products in biofluids of moderate preterm infants

Oxidative stress plays an essential role in processes of signaling and damage to biomolecules during early perinatal life. Isoprostanoids and isofuranoids from the free radical-catalyzed peroxidation of polyunsaturated fatty acids (PUFAs) are widely recognized as reliable biomarkers of oxidative stress. However, their quantification is not straightforward due to high structural similarity of the compounds formed. In this work, a semiquantitative method for the analysis of adrenic acid (AdA, C22:4 n-6) non-enzymatic peroxidation products (i.e. dihomo-isoprostanes and dihomo-isofurans) was developed. The proposed ultra-performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS) method was applied to the analysis of blood plasma and urine from preterm infants providing information about AdA peroxidation.

Brain oxidative damage in murine models of neonatal hypoxia/ischemia and reoxygenation

The brain is one of the main organs affected by hypoxia and reoxygenation in the neonatal period and one of the most vulnerable to oxidative stress. Hypoxia/ischemia and reoxygenation leads to impairment of neurogenesis, disruption of cortical migration, mitochondrial damage and neuroinflammation. The extent of the injury depends on the clinical manifestation in the affected regions. Preterm newborns are highly vulnerable, and they exhibit severe clinical manifestations such as intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP) and diffuse white matter injury (DWMI) among others. In the neonatal period, the accumulation of high levels of reactive oxygen species exacerbated by the immature antioxidant defense systems in represents cellular threats that, if they exceed or bypass physiological counteracting mechanisms, are responsible of significant neuronal damage. Several experimental models in mice mimic the consequences of perinatal asphyxia and the use of oxygen in the reanimation process that produce brain injury. The aim of this review is to highlight brain damage associated with oxidative stress in different murine models of hypoxia/ischemia and reoxygenation.

Increased isoprostanoid levels in brain from murine model of Krabbe disease - Relevance of isoprostanes, dihomo-isoprostanes and neuroprostanes to disease severity

Krabbe disease (KD) is a rare and devastating pediatric leukodystrophy caused by mutations in the galactocerebrosidase (GALC) gene. The disease leads to impaired myelin formation and extensive myelin damage in the brain. Oxidative stress is implicated in the pathogenesis of KD but insofar few information is available. The gray and white matter of the brain are rich in docosahexaenoic acid and adrenic acid respectively and under non-enzymatic oxidative stress, release isoprostanoids, i.e. F₄-neuroprostanes (F₄-NeuroPs) and F₂-dihomo-isoprostanes (F₂-dihomo-IsoPs). In this study, the formation of isoprostanoids in brain tissue was investigated in a well-established KD mouse model (twitcher) that recapitulates the human pathology. According to the genotype determinations, three groups of mice were selected: wild-type control mice (n = 13), heterozygotes mice (carriers of GALC mutations, n = 14) and homozygous twitcher mice (n = 13). Measurement of F₂-dihomo-IsoP and F₄-NeuroP levels were performed on whole brain tissue obtained at day 15 and day 35 of the life cycle. Brain isoprostanoid levels were significantly higher in the twitcher mice compared to the heterozygous and wild-type control mice. However, F₂-dihomo-IsoP and F₄-NeuroP levels did not differ in brain of day 15 compared to day 35 of the heterozygote mice. Interestingly, isoprostanoid levels were proportionally enhanced with disease severity (F₂-dihomo-IsoPs, rho = 0.54; F₄-NeuroPs, rho = 0.581; P values ≤ 0.05; n = 13). Our findings are the first to show the key role of polyunsaturated fatty acid oxidative damage to brain grey and white matter in the pathogenesis and progression of KD. This shed new insights on the biochemical indexes of KD progression, and potentially provide information for novel therapeutic targets.

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.

Stereoselective preparation of key intermediates for the synthesis of iso-, neuro- and phyto-prostane family members: inaugural asymmetric synthesis of 17-E2c-dihomo- and 17-F2c-dihomo-isoprostanes

A practical methodology for the synthesis of key intermediates for isoprostane, neuroprostane and dihomo-isoprostane preparation has been described. The key strategy involved a three stage C-12 stereocenter inversion of the configuration of a Corey lactone, commercially available in an enantiopure form. The key intermediate was then used to prepare 17-E2c-dihomo-isoprostane and 17-F2c-dihomo-isoprostane.

Newly validated biomarkers of brain damage may shed light into the role of oxidative stress in the pathophysiology of neurocognitive impairment in dietary restricted phenylketonuria patients

Despite a strict dietary control, patient with hyperphenylalaninemia or phenylketonuria may show cognitive and/or behavioral disorders. These comorbid deficits are of great concern to patients, families, and health organizations. However, biomarkers capable of detecting initial stages of neurological damage are not commonly employed. The pathogenesis of phenylketonuria is complex in nature. Increasingly, the role of oxidative stress has gained acceptance and biomarkers reflecting oxidative damage to the brain and easily accessible in peripheral biofluids have been validated using mass spectrometry techniques. In the present review, the role of oxidative stress in the pathogenesis of phenylketonuria and hyperphenylalaninemia has been updated. Moreover, we report on newly validated brain-specific lipid peroxidation biomarkers and inform on their relevance in the detection and monitoring of neurological damage in phenylketonuric patients. In preliminary studies, a correlation between lipid peroxidation biomarkers and neurological dysfunction in patients with PKU was reported. However, there is a need of adequately powered trials to confirm the validity of these biomarkers for early detection of brain damage, initiation of treatment, and reliably monitor evolving disease both in phenylketonuria and hyperphenylalaninemia.

Regional differences of hypothermia on oxidative stress following hypoxia-ischemia: a study of DHA and hypothermia on brain lipid peroxidation in newborn piglets

Background Oxidative stress plays an important part in the pathophysiology of hypoxic-ischemic encephalopathy (HIE) and is reliably measured through prostanoids following lipid peroxidation of polyunsaturated fatty acids (PUFAs). The aim of the study is to measure oxidative stress in the prefrontal cortex, white matter and hippocampus in the brains of hypoxic-ischemic piglets treated with docosahexaenoic acid (DHA) and therapeutic hypothermia (TH) and investigate the additive effects of DHA on hypothermia by factorial design. Methods Fifty-five piglets were randomized as having severe global hypoxia (n=48) or not (sham, n=7). Hypoxic piglets were further randomized: vehicle (VEH), DHA, VEH+hypothermia (HT) or HT+DHA. A total of 5 mg/kg DHA was given intravenously 210 min after the end of hypoxia. Brain tissues were analyzed using liquid chromatography triple quadrupole mass spectrometry technique (LC-MS). A two-way analysis of variance (ANOVA) was performed with DHA and HT as main effects. Results In the white matter, we found main effects of DHA on DH-isoprostanes (P=0.030) and a main effect of HT on F4-neuroprostanes (F4-NeuroPs) (P=0.007), F2-isoprostanes (F2-IsoPs) (P=0.043) and DH-isoprostanes (P=0.023). In the cortex, the ANOVA analysis showed the interactions of main effects between DHA and HT for neurofuranes (NeuroFs) (P=0.092) and DH-isoprostanes (P=0.015) as DHA significantly reduced lipid peroxidation in the absence of HT. DHA compared to VEH significantly reduced NeuroFs (P=0.019) and DH-isoprostanes (P=0.010). No differences were found in the hippocampus. Conclusion After severe hypoxia, HT reduced lipid peroxidation in the white matter but not in the cortical gray matter. HT attenuated the reducing effect of DHA on lipid peroxidation in the cortex. Further studies are needed to determine whether DHA can be an effective add-on therapy for TH.

Isoprostanoids in Clinical and Experimental Neurological Disease Models

Isoprostanoids are a large family of compounds derived from non-enzymatic oxidation of polyunsaturated fatty acids (PUFAs). Unlike other oxidative stress biomarkers, they provide unique information on the precursor of the targeted PUFA. Although they were discovered about a quarter of century ago, the knowledge on the role of key isoprostanoids in the pathogenesis of experimental and human disease models remains limited. This is mainly due to the limited availability of highly purified molecules to be used as a reference standard in the identification of biological samples. The accurate knowledge on their biological relevance is the critical step that could be translated from some mere technical/industrial advances into a reliable biological disease marker which is helpful in deciphering the oxidative stress puzzle related to neurological disorders. Recent research indicates the value of isoprostanoids in predicting the clinical presentation and evolution of the neurological diseases. This review focuses on the relevance of isoprostanoids as mediators and potential biomarkers in neurological diseases, a heterogeneous family ranging from rare brain diseases to major health conditions that could have worldwide socioeconomic impact in the health sector. The current challenge is to identify the preferential biochemical pathways that actually follow the oxidative reactions in the neurological diseases and the consequence of the specific isoprostanes in the underlying pathogenic mechanisms.

Melatonin and hydroxytyrosol protect against oxidative stress related to the central nervous system after the ingestion of three types of wine by healthy volunteers

Adrenic acid (AdA) and docosahexaenoic acid (DHA) peroxidation produces F₂-dihomo-IsoPs and neuroprostanes, which have been related to oxidative damage in the central nervous system. Besides polyphenols, melatonin (MEL) and hydroxytyrosol (OHTyr) could be partly responsible for the antioxidant benefits of red wine (excluding colon derivatives). In order to elucidate whether these compounds are responsible for the protective antioxidant effects of red wine, a double-blind, crossover, placebo-controlled in vivo study - involving the intake of red wines and their native musts by healthy volunteers - was performed. The urinary metabolites decreased after the administration of red wines, to a greater extent than after the intake of their corresponding musts or ethanol. Melatonin is the most effective compound that protects adrenic acid from oxidative attack, judged by the reduction in the formation of F₂-dihomo-isoprostanes. Similarly, hydroxytyrosol, being the most effective bioactive compound in reducing the formation of F₃-neuroprostanes n-6 DPA and F₄-neuroprostanes, protected docosahexaenoic and eicosapentaenoic acids from oxidative attack.

Therapeutic Strategies for Leukodystrophic Disorders Resulting from Perinatal Asphyxia: Focus on Myelinating Oligodendrocytes

Perinatal asphyxia results from the action of different risk factors like complications during pregnancy, preterm delivery, or long and difficult labor. Nowadays, it is still the leading cause of neonatal brain injury known as hypoxic-ischemic encephalopathy (HIE) and resulting neurological disorders. A temporal limitation of oxygen, glucose, and trophic factors supply results in alteration of neural cell differentiation and functioning and/or leads to their death. Among the affected cells are oligodendrocytes, responsible for myelinating the central nervous system (CNS) and formation of white matter. Therefore, one of the major consequences of the experienced HIE is leukodystrophic diseases resulting from oligodendrocyte deficiency or malfunctioning. The therapeutic strategies applied after perinatal asphyxia are aimed at reducing brain damage and promoting the endogenous neuroreparative mechanisms. In this review, we focus on the biology of oligodendrocytes and discuss present clinical treatments in the context of their efficiency in preserving white matter structure and preventing cognitive and behavioral deficits after perinatal asphyxia.

Development of an LC-ESI(-)-MS/MS method for the simultaneous quantification of 35 isoprostanes and isofurans derived from the major n3- and n6-PUFAs

Misregulation of oxidative and antioxidative processes in the organism - oxidative stress - contributes to the pathogenesis of different diseases, e.g. inflammatory or neurodegenerative diseases. Oxidative stress leads to autoxidation of polyunsaturated fatty acids giving rise to prostaglandin-like isoprostanes (IsoP) and isofurans (IsoF). On the one hand they could serve as biomarker of oxidative stress and on the other hand may act as lipid mediators, similarly as the enzymatically formed oxylipins. In the present paper we describe the development of an LC-ESI(-)-MS/MS method allowing the parallel quantification of 27 IsoP and 8 IsoF derived from 6 different PUFA (ALA, ARA, EPA, AdA, n6-DPA, DHA) within 12 min. The chromatographic separation was carried out on an RP-C18 column (2.1 × 150 mm, 1.8 μm) yielding narrow peaks with an average width at half maximum of 3.3-4.2 s. Detection was carried out on a triple quadrupole mass spectrometer operating in selected reaction monitoring mode allowing the selective detection of regioisomers. The limit of detection ranged between 0.1 and 1 nM allowing in combination with solid phase extraction the detection of IsoP and IsoF at subnanomolar concentrations in biological samples. The method was validated for human plasma showing high accuracy and precision. Application of the approach on the investigation of oxidative stress in cultured cells indicated a distinct pattern of IsoP and IsoF in response to reactive oxygen species which warrants further investigation. The described method is not only the most comprehensive approach for the simultaneous quantification of IsoP and IsoF, but it was also integrated in a targeted metabolomics method (Ostermann et al. (2015) Anal Bioanal Chem) allowing the quantification of in total 164 oxylipins formed enzymatically and non-enzymatically within 30.5 min.

Isoprostanes, neuroprostanes and phytoprostanes: An overview of 25years of research in chemistry and biology

Since the beginning of the 1990's diverse types of metabolites originating from polyunsaturated fatty acids, formed under autooxidative conditions were discovered. Known as prostaglandin isomers (or isoprostanoids) originating from arachidonic acid, neuroprostanes from docosahexaenoic acid, and phytoprostanes from α-linolenic acid proved to be prevalent in biology. The syntheses of these compounds by organic chemists and the development of sophisticated mass spectrometry methods has boosted our understanding of the isoprostanoid biology. In recent years, it has become accepted that these molecules not only serve as markers of oxidative damage but also exhibit a wide range of bioactivities. In addition, isoprostanoids have emerged as indicators of oxidative stress in humans and their environment. This review explores in detail the isoprostanoid chemistry and biology that has been achieved in the past three decades.

Snapshot situation of oxidative degradation of the nervous system, kidney, and adrenal glands biomarkers-neuroprostane and dihomo-isoprostanes-urinary biomarkers from infancy to elderly adults

We analyzed biomarkers of lipid peroxidation of the nervous system -F₂-dihomo-isoprostanes, F₃-neuroprostanes, and F₄-neuroprostanes- in urine samples from 158 healthy volunteers ranging from 4 to 88 years old with the aim of analyzing possible associations between their excretion values and age (years). Ten biomarkers were screened in the urine samples by UHPLC-QqQ-MS/MS. Four F₂-dihomo-isoprostanes (ent-7-(R)-7-F_2t-dihomo-isoprostane, ent-7-epi-7-F_2t-dihomo-isoprostane, 17-F_2t-dihomo-isoprostane, 17-epi-17-F_2t-dihomo-isoprostane), and one DPA-neuroprostane (4-F_3t-neuroprostane) were detected in the samples. On the one hand, we found a significant, positive correlation (Rho: 0.197, P=0.015) between the age increase and the amount of total F₂-dihomo-IsoPs. On the other hand, the values were significantly higher in the childhood group (4-12 years old), when compared to the adolescence group (13-17 years old) and the young adult group (18-35 years old). Surprisingly, no significant differences were found between the middle-aged adults (36-64 years old) and the elderly adults (65-88 years old). We display a snapshot situation of excretory values of oxidative stress biomarkers of the nervous system, using healthy volunteers representative of the different stages of human growth and development. The values reported in this study could be used as a basal or starting point in clinical interventions related to aging processes and/or pathologies associated with the nervous system.

DHA Reduces Oxidative Stress after Perinatal Asphyxia: A Study in Newborn Piglets

BACKGROUND

Perinatal hypoxic-ischemic brain damage is a major cause of acute mortality and chronic neurological morbidity in infants and children. Oxidative stress due to free radical formation and the initiation of abnormal oxidative reactions appears to play a key role. Docosahexanoic acid (DHA), a main component of brain membrane phospholipids, may act as a neuroprotectant after hypoxia-ischemia by regulating multiple molecular pathways and gene expression.

OBJECTIVES

The aims of this study were to test the hypothesis that DHA provides significant protection against lipoperoxidation damage in the cerebral cortex and hippocampus in a neonatal piglet model of severe hypoxia-reoxygenation.

METHODS

Newborn piglets, Noroc (LYLD), were subjected to severe global hypoxia. One group was resuscitated with ambient air (21% group, n = 11) and another also received 5 mg/kg of DHA 4 h after the end of hypoxia (21% DHA group, n = 10). After 9.5 h, tissues from the prefrontal cortex and hippocampus were sampled and the levels of isoprostanes, neuroprostanes, neurofurans, and F2-dihomo-isoprostanes were determined by the liquid chromatography triple quadrupole mass spectrometry technique.

RESULTS

Lipid peroxidation biomarkers were significantly lower in both the cortex and hippocampus in the DHA-treated group compared with the untreated group.

CONCLUSIONS

The present study demonstrates that DHA administration after severe hypoxia in newborn piglets has an antioxidative effect in the brain, suggesting a protective potential of DHA if given after injuries to the brain.

Assessment of Isoprostanes in Human Plasma: Technical Considerations and the Use of Mass Spectrometry

Oxygenated lipid mediators released from non-enzymatic peroxidation of polyunsaturated fatty acids (PUFA) are known to have functional roles in humans. Notably, among these lipid mediators, isoprostanes molecules are robust biomarkers of oxidative stress but those from n-3 PUFA are also bioactive molecules. In order to identify and assess the isoprostanes, the use of mass spectrometry (MS) for analysis is preferable and has been used for over two decades. Gas chromatography (GC) is commonly coupled to the MS to separate the derivatized isoprostanes of interest in biological samples. In order to increase the accuracy of the analytical performance, GC-MS/MS was also applied. Lately, MS or MS/MS has been coupled with high-performance liquid chromatography to assess multiple isoprostane molecules in a single biological sample without derivatization process. However, there are limitations for the use of LC-MS/MS in the measurement of plasma isoprostanes, which will be discussed in this review.

MECP2 Duplication Syndrome: Evidence of Enhanced Oxidative Stress. A Comparison with Rett Syndrome

Rett syndrome (RTT) and MECP2 duplication syndrome (MDS) are neurodevelopmental disorders caused by alterations in the methyl-CpG binding protein 2 (MECP2) gene expression. A relationship between MECP2 loss-of-function mutations and oxidative stress has been previously documented in RTT patients and murine models. To date, no data on oxidative stress have been reported for the MECP2 gain-of-function mutations in patients with MDS. In the present work, the pro-oxidant status and oxidative fatty acid damage in MDS was investigated (subjects n = 6) and compared to RTT (subjects n = 24) and healthy condition (subjects n = 12). Patients with MECP2 gain-of-function mutations showed increased oxidative stress marker levels (plasma non-protein bound iron, intraerythrocyte non-protein bound iron, F₂-isoprostanes, and F₄-neuroprostanes), as compared to healthy controls (P ≤ 0.05). Such increases were similar to those observed in RTT patients except for higher plasma F₂-isoprostanes levels (P < 0.0196). Moreover, plasma levels of F₂-isoprostanes were significantly correlated (P = 0.0098) with the size of the amplified region. The present work shows unique data in patients affected by MDS. For the first time MECP2 gain-of-function mutations are indicated to be linked to an oxidative damage and related clinical symptoms overlapping with those of MECP2 loss-of-function mutations. A finely tuned balance of MECP2 expression appears to be critical to oxidative stress homeostasis, thus shedding light on the relevance of the redox balance in the central nervous system integrity.

Lipidomic approach in young adult triathletes: effect of supplementation with a polyphenols-rich juice on neuroprostane and F2-dihomo-isoprostane markers

With adequate training, our juice rich in polyphenolic compounds has been able to influence the excretion values of oxidative stress biomarkers associated with the central nervous system.

Special Issue on "Analytical Methods for Oxidized Biomolecules and Antioxidants" The use of isoprostanoids as biomarkers of oxidative damage, and their role in human dietary intervention studies

Isoprostanoids are a group of non-enzymatic oxidized lipids from polyunsaturated fatty acids. They are commonly used as biomarkers for oxidative damage, to assess in vivo lipid peroxidation in diseases related to the vascular system and neurodegeneration. Currently, there is a mismatch with the outcome in the use of these biomarkers in intervention studies, particularly when testing the effect of antioxidants such as vitamins C and E, or zinc, or a cocktail of these, with other food components. Much of this is because the biomarkers, the method of measurement, and the duration of supplementation are unsuitable. In this review, we will highlight the formation of isoprostanoids from their respective fatty acids, and their application as biomarkers for oxidative damage in vivo, considering human dietary intervention studies evaluating plasma and urine, using mass spectrometry techniques.

Dihomo-isoprostanes-nonenzymatic metabolites of AdA-are higher in epileptic patients compared to healthy individuals by a new ultrahigh pressure liquid chromatography-triple quadrupole-tandem mass spectrometry method

Oxidative stress is a biochemical state in which reactive oxygen species are generated and it has been associated with pathological states including epilepsy. Therein, neuroprostanes (NeuroPs) and dihomo-isoprostanes (Dihomo-IsoPs)-a series of compounds formed nonenzymatically through free radical-induced DHA, n-6 DPA, and AdA peroxidation-are implicated in the pathophysiological status of various human neurological diseases. A new, robust, and selective analytical method for the determination of 10 NeuroPs/Dihomo-IsoPs in human urine, using solid-phase extraction and UHPLC-QqQ-MS/MS in the multiple reaction monitoring mode (using a negative electrospray ionization interface), was developed. Nine NeuroPs/Dihomo-IsoPs were identified in 15 epileptic patients, matched with healthy volunteers. Among them, 17-F2t-Dihomo-IsoP, Ent-7(R)-7-F2t-Dihomo-IsoP, and Ent-7-epi-7-F2t-Dihomo-IsoP, derived from adrenic acid (AdA), were significantly higher in epileptic patients than in healthy volunteers. The validated method provided a high-throughput assay with a limit of detection and limit of quantification for each analyte of 0.10-5.90ngmL(-1) and 0.15-11.81ngmL(-1), respectively. The intra- and interday variations were lower than 14%. Dihomo-IsoPs have been considered as potential markers of epilepsy for the first time and their measurement may increase the understanding of the role of oxidative stress in neurological diseases, in intra vitam studies. The present study highlights a potential role of Dihomo-IsoPs as biomarkers in persons with epilepsy, though its mechanisms and possible implications should be the subject of further investigations.

Non-enzymatic cyclic oxygenated metabolites of adrenic, docosahexaenoic, eicosapentaenoic and α-linolenic acids; bioactivities and potential use as biomarkers

Cyclic oxygenated metabolites are formed in vivo through non-enzymatic free radical reaction of n-6 and n-3 polyunsaturated fatty acids (PUFAs) such as arachidonic (ARA C20:4 n-6), adrenic (AdA 22:4 n-6), α-linolenic (ALA 18:3 n-3), eicosapentaenoic (EPA 20:5 n-3) and docosahexaenoic (DHA 22:6 n-3) acids. These cyclic compounds are known as isoprostanes, neuroprostanes, dihomo-isoprostanes and phytoprostanes. Evidence has emerged for their use as biomarkers of oxidative stress and, more recently, the n-3PUFA-derived compounds have been shown to mediate bioactivities as secondary messengers. Accordingly, this review will focus on the cyclic oxygenated metabolites generated from AdA, ALA, EPA and DHA. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

Current development in non-enzymatic lipid peroxidation products, isoprostanoids and isofuranoids, in novel biological samples

Isoprostanoids and isofuranoids are lipid mediators that can be formed from omega-3 and omega-6 polyunsaturated fatty acids (PUFAs). F2-isoprostanes formed from arachidonic acid, especially 15-F2t-isoprostane, are commonly measured in biological tissues for decades as the biomarker for oxidative stress and diseases. Recently, other forms of isoprostanoids derived from adrenic, eicosapentaenoic, and docosahexaenoic acids namely F2-dihomo-isoprostanes, F3-isoprostanes, and F4-neuroprostanes respectively, and isofuranoids including isofurans, dihomo-isofurans, and neurofurans are reported as oxidative damage markers for different metabolisms. The most widely used samples in measuring lipid peroxidation products include but not limited to the blood and urine; other biological fluids, specialized tissues, and cells can also be determined. In this review, measurement of isoprostanoids and isofuranoids in novel biological samples by gas chromatography (GC)-mass spectrometry (MS), GC-MS/MS, liquid chromatography (LC)-MS, and LC-MS/MS will be discussed.

Non-enzymatic lipid oxidation products in biological systems: assessment of the metabolites from polyunsaturated fatty acids

Metabolites of non-enzymatic lipid peroxidation of polyunsaturated fatty acids notably omega-3 and omega-6 fatty acids have become important biomarkers of lipid products. Especially the arachidonic acid-derived F2-isoprostanes are the classic in vivo biomarker for oxidative stress in biological systems. In recent years other isoprostanes from eicosapentaenoic, docosahexaenoic, adrenic and α-linolenic acids have been evaluated, namely F3-isoprostanes, F4-neuroprostanes, F2-dihomo-isoprostanes and F1-phytoprostanes, respectively. These have been gaining interest as complementary specific biomarkers in human diseases. Refined extraction methods, robust analysis and elucidation of chemical structures have improved the sensitivity of detection in biological tissues and fluids. Previously the main reliable instrumentation for measurement was gas chromatography-mass spectrometry (GC-MS), but now the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunological techniques is gaining much attention. In this review, the types of prostanoids generated from non-enzymatic lipid peroxidation of some important omega-3 and omega-6 fatty acids and biological samples that have been determined by GC-MS and LC-MS/MS are discussed.

Optimized method for quantification of total F(2)-isoprostanes using gas chromatography-tandem mass spectrometry

F2-isoprostanes are produced from the oxidative degradation of arachidonic acid and are considered the gold standard marker of lipid peroxidation in biological samples. We developed a liquid-liquid extraction method for the determination of total isoprostanes using negative chemical ionization gas chromatography-tandem mass spectrometry in plasma and tissue homogenates. Incorporating liquid-liquid extraction allows for greater sample through-put than current approaches. Here we describe the protocol and include numerous trouble-shooting suggestions. The method found healthy individuals with 150-250 pg of isoprostanes per ml of plasma and end stage kidney disease patients to have the highest measured values of up to 1100 pg/ml. This assay has an accurate working linear range of 40-1000 pg of isoprostanes (100-2500 pg/ml) and an average coefficient of variance of 7%. Tissue values for healthy mice liver were 50-70 pg/μg protein. This method provides increased ion selectivity and detection capabilities with economical sample through-put.

Lipidomics of essential fatty acids and oxygenated metabolites

Polyunsaturated fatty acids in mammals may be oxygenated into a myriad of bioactive products through di- and monooxygenases, products that are rapidly degraded to control their action. To evaluate the phenotypes of biological systems regarding this wide family of compounds, a lipidomics approach in function of time and compartments would be relevant. The current review takes into consideration most of the diverse oxygenated metabolites of essential fatty acids at large and their immediate degradation products. Their biological function and life span are considered. Overall, this is a fluxolipidomics approach that is emerging.

Isoprostanes and 4-hydroxy-2-nonenal: markers or mediators of disease? Focus on Rett syndrome as a model of autism spectrum disorder

Lipid peroxidation, a process known to induce oxidative damage to key cellular components, has been implicated in several diseases. Following three decades of explorations mainly on in vitro models reproducible in the laboratories, lipid peroxidation has become increasingly relevant for the interpretation of a wide range of pathophysiological mechanisms in the clinical setting. This cumulative effort has led to the identification of several lipid peroxidation end-products meeting the needs of the in vivo evaluation. Among these different molecules, isoprostanes and 4-hydroxy-2-nonenal protein adducts appear to be particularly interesting. This review shows how specific oxidation products, deriving from polyunsaturated fatty acids precursors, are strictly related to the clinical manifestations and the natural history of Rett syndrome, a genetically determined neurodevelopmental pathology, currently classified among the autism spectrum disorders. In our experience, Rett syndrome offers a unique setting for physicians, biologists, and chemists to explore the borders of the lipid mediators concept.

Isoprostanes and neuroprostanes: total synthesis, biological activity and biomarkers of oxidative stress in humans

Isoprostanes (IsoPs) and neuroprostanes (NeuroPs) are formed in vivo by a free radical non-enzymatic mechanism involving peroxidation of arachidonic acid (AA, C20:4 n-6) and docosahexaenoic acid (DHA, C22:6 n-3) respectively. This review summarises our research in the total synthesis of these lipid metabolites, as well as their biological activities and their utility as biomarkers of oxidative stress in humans.

The role of oxidative stress in Rett syndrome: an overview

The main cause of Rett syndrome (RTT), a pervasive development disorder almost exclusively affecting females, is a mutation in the methyl-CpG binding protein 2 (MeCP2) gene. To date, no cure for RTT exists, although disease reversibility has been demonstrated in animal models. Emerging evidence from our and other laboratories indicates a potential role of oxidative stress (OS) in RTT. This review examines the current state of the knowledge on the role of OS in explaining the natural history, genotype-phenotype correlation, and clinical heterogeneity of the human disease. Biochemical evidence of OS appears to be related to neurological symptom severity, mutation type, and clinical presentation. These findings pave the way for potential new genetic downstream therapeutic strategies aimed at improving patient quality of life. Further efforts in the near future are needed for investigating the yet unexplored "black box" between the MeCP2 gene mutation and subsequent OS derangement.

Phospholipid sources for adrenic acid mobilization in RAW 264.7 macrophages. Comparison with arachidonic acid

Cells metabolize arachidonic acid (AA) to adrenic acid (AdA) via 2-carbon elongation reactions. Like AA, AdA can be converted into multiple oxygenated metabolites, with important roles in various physiological and pathophysiological processes. However, in contrast to AA, there is virtually no information on how the cells regulate the availability of free AdA for conversion into bioactive products. We have used a comparative lipidomic approach with both gas chromatography and liquid chromatography coupled to mass spectrometry to characterize changes in the levels of AA- and AdA-containing phospholipid species in RAW 264.7 macrophage-like cells. Incubation of the cells with AA results in an extensive conversion to AdA but both fatty acids do not compete with each other for esterification into phospholipids. AdA but not AA, shows preference for incorporation into phospholipids containing stearic acid at the sn-1 position. After stimulation of the cells with zymosan, both AA and AdA are released in large quantities, albeit AA is released to a greater extent. Finally, a variety of phosphatidylcholine and phosphatidylinositol molecular species contribute to AA; however, AdA is liberated exclusively from phosphatidylcholine species. Collectively, these results identify significant differences in the cellular utilization of AA and AdA by the macrophages, suggesting non-redundant biological actions for these two fatty acids.

Adult Changes in Thought study: dementia is an individually varying convergent syndrome with prevalent clinically silent diseases that may be modified by some commonly used therapeutics

The Adult Changes in Thought (ACT) study is a longitudinal population-based prospective cohort study of brain aging and incident dementia in the Seattle metropolitan area. Observational studies using autopsies from ACT indicate that dementia is a convergent syndrome that commonly derives from Alzheimer's disease (AD), microvascular brain injury (mVBI), and Lewy body disease (LBD), and that these diseases have prevalent subclinical forms that also are commonly co-morbid. The existence of subclinical diseases highlights potential opportunities to intervene before the development of clinically apparent impairments. Our observations suggest that some such interventions already may exist to suppress processes of AD (statin therapy) or mVBI (treatment of hypertension). Reduced burden of LBD is associated with cigarette smoking; although smoking is not recommended as an intervention, these exposure data may provide clues to alternative neuroprotective mechanisms. Self reported anti-oxidant supplementation was without apparent effect in this cohort on indices of AD, mVBI, or LBD. Continued observational studies of brain aging will provide further insight into the convergent complexity of the dementia syndrome and its subclinical forms as well as highlight potential interventions that will require validation in clinical trials.