Eicosanoids

Sex Hormone-Dependent Lipid Mediator Formation in Male and Female Mice During Peritonitis

Introduction: Sex differences in inflammation are obvious and contribute to divergences in the incidence and severity of inflammation-related diseases that frequently preponderate in women. Lipid mediators (LMs), mainly produced by lipoxygenase (LOX) and cyclooxygenase (COX) pathways from polyunsaturated fatty acids (PUFAs), regulate all stages of inflammation. Experimental and clinical studies revealed sex divergences for selected LM pathways without covering the entire LM spectrum, and only few studies have addressed the respective role of sex hormones. Here, we performed the comprehensive LM profile analysis with inflammatory peritoneal exudates and plasma from male and female mice in zymosan-induced peritonitis to identify the potential sex differences in LM biosynthesis during the inflammatory response. We also addressed the impact of sex hormones by employing gonadectomy. Methods: Adult male and female CD1 mice received intraperitoneal injection of zymosan to induce peritonitis, a well-established experimental model of acute, self-resolving inflammation. Mice were gonadectomized 5 weeks prior to peritonitis induction. Peritoneal exudates and plasma were taken at 4 (peak of inflammation) and 24 h (onset of resolution) post zymosan and subjected to UPLC-MS-MS-based LM signature profiling; exudates were analyzed for LM biosynthetic proteins by Western blot; and plasma was analyzed for cytokines by ELISA. Results: Pro-inflammatory COX and 5-LOX products predominated in the peritoneum of males at 4 and 24 h post-zymosan, respectively, with slightly higher 12/15-LOX products in males after 24 h. Amounts of COX-2, 5-LOX/FLAP, and 15-LOX-1 were similar in exudates of males and females. In plasma of males, only moderate elevation of these LMs was apparent. At 4 h post-zymosan, gonadectomy strongly elevated 12/15-LOX products in the exudates of males, while in females, free PUFA and LOX products were rather impaired. In plasma, gonadectomy impaired most LMs in both sexes at 4 h with rather up-regulatory effects at 24 h. Finally, elevated 15-LOX-1 protein was evident in exudates of males at 24 h which was impaired by orchiectomy without the striking impact of gonadectomy on other enzymes in both sexes. Conclusions: Our results reveal obvious sex differences and roles of sex hormones in LM biosynthetic networks in acute self-resolving inflammation in mice, with several preponderances in males that appear under the control of androgens.

Pro-resolving and pro-inflammatory fatty acid-derived mediators in sputum of stable state bronchiectasis patients

BACKGROUND

Bronchiectasis is characterized by neutrophilic inflammation and frequent exacerbations often associated with infections. Lipid mediators play critical roles in the inflammatory response, and the balance between anti-inflammatory and pro-inflammatory mediators could drive to chronic inflammation. The aim of this study was to evaluate the metabolites of docosahexaenoic acid and arachidonic acid in sputum of adults with bronchiectasis defining their associations with clinical data, bacterial load and neutrophil elastase.

METHODS

An observational, cross-sectional study was conducted at the bronchiectasis program of the Policlinico Hospital in Milan, Italy, where patients were enrolled. Active neutrophil elastase was measured by enzyme-linked immunosorbent assay, pro-resolving and pro-inflammatory fatty acid-derived mediators were evaluated by mass spectrometry and respiratory pathogens were assessed by real-time PCR. Analysis were performed on sputum collected during stable state and clinical data were also collected.

RESULTS

Levels of pro-inflammatory mediators derived from arachidonic acid metabolism showed association with neutrophil elastase, were proportional to Pseudomonas aeruginosa identifications and were linked with radiological gravity index, while the concentrations of pro-resolution mediators derived from docosahexaenoic acid were associated with a better health status, highlighted by the inverse correlation with radiological gravity index, bacterial infections and sputum volume production.

CONCLUSION

Pro-inflammatory mediators derived from FA metabolisms are associated with severity of bronchiectasis while DHA-derived metabolites are inversely associated with severity of the disease, which may be used for personized treatment of bronchiectasis.

Inflammatory Effects of Bothrops Phospholipases A2: Mechanisms Involved in Biosynthesis of Lipid Mediators and Lipid Accumulation

Phospholipases A₂s (PLA₂s) constitute one of the major protein groups present in the venoms of viperid and crotalid snakes. Snake venom PLA₂s (svPLA₂s) exhibit a remarkable functional diversity, as they have been described to induce a myriad of toxic effects. Local inflammation is an important characteristic of snakebite envenomation inflicted by viperid and crotalid species and diverse svPLA₂s have been studied for their proinflammatory properties. Moreover, based on their molecular, structural, and functional properties, the viperid svPLA₂s are classified into the group IIA secreted PLA₂s, which encompasses mammalian inflammatory sPLA₂s. Thus, research on svPLA₂s has attained paramount importance for better understanding the role of this class of enzymes in snake envenomation and the participation of GIIA sPLA₂s in pathophysiological conditions and for the development of new therapeutic agents. In this review, we highlight studies that have identified the inflammatory activities of svPLA₂s, in particular, those from Bothrops genus snakes, which are major medically important snakes in Latin America, and we describe recent advances in our collective understanding of the mechanisms underlying their inflammatory effects. We also discuss studies that dissect the action of these venom enzymes in inflammatory cells focusing on molecular mechanisms and signaling pathways involved in the biosynthesis of lipid mediators and lipid accumulation in immunocompetent cells.

The effect of long chain omega-3 polyunsaturated fatty acids on muscle mass and function in sarcopenia: A scoping systematic review and meta-analysis

BACKGROUND & AIMS

Sarcopenia is characterized by the progressive loss of skeletal muscle mass and function, which reduces mobility and quality of life. Risk factors for sarcopenia include advanced age, physical inactivity, obesity, and chronic diseases such as cancer or rheumatoid arthritis. Omega-3 long chain polyunsaturated fatty acids (LC PUFAs) might be associated with a reduction in risk of sarcopenia due to their anti-inflammatory effects.

METHODS

We conducted a systematic review and meta-analysis to quantify the effects of omega-3 LC PUFAs on muscle mass, volume and function parameters. The National Library of Medicine's MEDLINE/PubMed database was searched on 9th October 2020 for randomized controlled trials that used omega-3 LC PUFAs as an intervention with muscle-related endpoints. A snowballing search to identify additional studies was completed on 23rd April 2021. The meta-analysis was conducted using meta-essentials worksheet 3. Bias was assessed using the Jadad scale.

RESULTS

123 studies were identified with the systematic searches. Most studies were performed in disease populations, such as cancer or chronic obstructive pulmonary disease (COPD), or in healthy individuals after a fatiguing exercise bout. The endpoints lean body mass, skeletal muscle mass, mid-arm muscle circumference, handgrip strength, quadriceps maximal voluntary capacity (MVC), and 1-repetition maximum chest press were selected for meta-analysis based on the number of available studies; thus 66 studies were included in the quantitative synthesis. Using a random effects model and 2-tailed p-value, there was a significant relationship in favor of omega-3 LC PUFA supplementation for lean body mass (effect size 0.27, 95%CI 0.04 to 0.51), skeletal muscle mass (effect size 0.31, 95%CI 0.01 to 0.60) and quadriceps MVC (effect size 0.47, 95%CI 0.02 to 0.93).

CONCLUSION

The results indicate that there is a positive effect of omega-3 LC PUFA supplementation on overall body muscle mass and strength. Small study size and heterogeneity limit the applicability of these findings for sarcopenia prevention. Larger trials in populations at risk of sarcopenia would strengthen the evidence base.

Comprehensive-targeted lipidomic analysis in Niemann-Pick C disease

Niemann-Pick C disease (NPC) is a lysosomal disease caused by mutations in NPC1 or NPC2 genes responsible for intracellular accumulation of free cholesterol and glycosphingolipids in a variety of tissues. We collected plasma samples from 15 NPC1 patients and 15 age-matched controls to analyze the impairment of lipid metabolism. Comprehensive-targeted quantitative lipidomic analysis was per-formed by Ion Mobility Mass Spectrometry, while oxysterols and lyso-sphingolipids, the classical NPC biomarkers, were analyzed by LC-MS/MS. Lipidomic analysis allowed the quantitation of ~1100 lipid species, belonging to 13 different classes. Statistical analysis of collected data showed a significant differentiation between NPC patients and controls. Lipid profiling showed an elevation of arachidonic acid and total diacylglycerols. Conversely, sphingomyelins, phosphatidylethano-lamines, phosphatidylcholines, cholesterylesters, and lactosylceramides were decreased. Indeed, the lipid imbalance was consistent with the increased concentrations of oxysterols and lyso-sphingolipids. Our study revealed a novel disease biosignature suggesting new potential diagnostic biomarkers. The alteration in key lipids molecules involved in inflammatory pathways and in oxidative stress regulation, provides new insights in the complex pathophysiology of the disease, still largely un-known.

Singapore Grouper Iridovirus Disturbed Glycerophospholipids Homeostasis: Cytosolic Phospholipase A2 Was Essential for Virus Replication

Singapore grouper iridovirus (SGIV), belonging to genus Ranavirus, family Iridoviridae, causes great economic losses in the aquaculture industry. Previous studies demonstrated the lipid composition of intracellular unenveloped viruses, but the changes in host-cell glyceophospholipids components and the roles of key enzymes during SGIV infection still remain largely unknown. Here, the whole cell lipidomic profiling during SGIV infection was analyzed using UPLC-Q-TOF-MS/MS. The lipidomic data showed that glycerophospholipids (GPs), including phosphatidylcholine (PC), phosphatidylserine (PS), glycerophosphoinositols (PI) and fatty acids (FAs) were significantly elevated in SGIV-infected cells, indicating that SGIV infection disturbed GPs homeostasis, and then affected the metabolism of FAs, especially arachidonic acid (AA). The roles of key enzymes, such as cytosolic phospholipase A2 (cPLA2), 5-Lipoxygenase (5-LOX), and cyclooxygenase (COX) in SGIV infection were further investigated using the corresponding specific inhibitors. The inhibition of cPLA2 by AACOCF3 decreased SGIV replication, suggesting that cPLA2 might play important roles in the process of SGIV infection. Consistent with this result, the ectopic expression of EccPLA2α or knockdown significantly enhanced or suppressed viral replication in vitro, respectively. In addition, the inhibition of both 5-LOX and COX significantly suppressed SGIV replication, indicating that AA metabolism was essential for SGIV infection. Taken together, our results demonstrated for the first time that SGIV infection in vitro disturbed GPs homeostasis and cPLA2 exerted crucial roles in SGIV replication.

Lipoxin A4 inhibits ovalbumin-induced airway inflammation and airway remodeling in a mouse model of asthma

Asthma is a chronic respiratory disease, which is characterized by airway inflammation, remodeling and airway hyperresponsiveness. Airway remodeling is caused by long-term inflammation of the airways. Lipoxin A4 (LXA4) is a natural eicosanoid with powerful anti-inflammatory properties, and has been shown to serve a critical role in orchestrating pulmonary inflammation and airway hyper-responsiveness in asthmatic mice. However, its effect on airway remodeling is unknown. Female BALB/c mice were used to establish a mouse model of asthma which were sensitized and challenged by ovalbumin (OVA). LXA4 was intranasally administrated prior to the challenge. The results of our study indicated that LXA4 suppressed the OVA-induced inflammatory cell infiltration and T helper type 2 (Th2) cytokines secretion in the mouse model of asthma. Characteristics of airway remodeling, such as thickening of the bronchial wall and smooth muscle, overdeposition of collagen, and overexpression of α-smooth muscle actin (α-SMA) and collagen-I were reversed by LXA4. Furthermore, LXA4 suppressed the aberrant activation of the signal transducer and activator of transcription 3 (STAT3) pathway in the lung tissues of asthmatic mice. In conclusion, these findings demonstrated that LXA4 alleviated allergic airway inflammation and remodeling in asthmatic mice, which may be related to the inhibition of STAT3 pathway.

Blood Fatty Acids Profile in MIS-C Children

MIS-C (multisystem inflammatory syndrome in children) linked to SARS-CoV-2 infection, is a pathological state observed in subjects younger than 21 years old with evidence of either current SARS-CoV-2 infection or exposure within the 4 weeks prior to the onset of symptoms, the presence of documented fever, elevated markers of inflammation, at least two signs of multisystem involvement, and, finally, lack of an alternative diagnosis. They share with adult COVID-19 patients the presence of altered markers of inflammation, but unlike most adults the symptoms are not pulmonary but are affecting several organs. Lipid mediators arising from polyunsaturated fatty acids (PUFA) play an important role in the inflammatory response, with arachidonic acid-derived compounds, such as prostaglandins and leukotrienes, mainly pro-inflammatory and ω3 PUFA metabolites such as resolvins and protectins, showing anti-inflammatory and pro-resolution activities. In order to assess potential alterations of these FA, we evaluated the blood fatty acid profile of MIS-C children at admission to the hospital, together with biochemical, metabolic and clinical assessment. All the patients enrolled showed altered inflammatory parameters with fibrinogen, D-dimer, NT-proBNP, ferritin, aspartate aminotransferase (AST), C-reactive protein (CRP) and TrygIndex levels over the reference values in all the subjects under observation, while albumin and HDL-cholesterol resulted below the normal range. Interestingly, linoleic acid (LA), arachidonic acid (AA) and the ω3 PUFA docosahexaenoic acid (DHA) results were lower in our study when compared to relative amounts reported in the other studies, including from our own laboratory. This significant alteration is pointing out to a potential depletion of these PUFA as a result of the systemic inflammatory condition typical of these patients, suggesting that LA- and AA-derived metabolites may play a critical role in this pathological state, while ω3 PUFA-derived pro-resolution metabolites in these subjects may not be able to provide a timely, physiological counterbalance to the formation of pro-inflammatory lipid mediators. In conclusion, this observational study provides evidence of FA alterations in MIS-C children, suggesting a significant contribution of ω6 FA to the observed inflammatory state, and supporting a potential dietary intervention to restore an appropriate balance among the FAs capable of promoting the resolution of the observed inflammatory condition.

Systemic Sclerosis: Elevated Levels of Leukotrienes in Saliva and Plasma Are Associated with Vascular Manifestations and Nailfold Capillaroscopic Abnormalities

The role of leukotrienes (LTs) in the pathogenesis of systemic sclerosis (SSc) needs clarification. We analyzed the association of salivary (sa) and plasma (p) levels (pg/mL) of cysteinyl-leukotrienes (CysLT) and LTB4 with SSc vascular manifestations and nailfold capillaroscopy (NFC) in a cross-sectional study. Patients and healthy controls were evaluated for vascular manifestations and NFC. LTs were compared between groups as follows: SSc with or SSc without vascular features and controls, and by NFC parameters. Twenty SSc patients and 16 volunteers were recruited; Raynaud's phenomenon (RP) history (SSc: saCysLT 99.4 ± 21.8 vs. controls: 23.05 ± 23.7, p = 0.01), RP at examination (SSc: saCysLT 129.3 ± 24.6 vs. controls: 23.05 ± 22.46, p = 0.01; pCysLT SSc: 87.5 ± 11.2 vs. controls: 32.37 ± 10.75, p = 0.002), capillary loss (saCysLT 138.6 ± 26.7 vs. 23.05 ± 21.6, p = 0.0007; saLTB4 3380.9 ± 426.6 vs. 1216.33 ± 346.1, p = 0.0005), "late" scleroderma pattern vs. controls (saCysLT 205.6 ± 32 vs. 23 ± 19.6, p = 0.0002; saLTB4 4564.9 ± 503.6 vs. 1216.3 ± 308.3; p < 0.0001) were all significant. Late patterns had higher levels (saCysLT, p = 0.002; LTB4 p = 0.0006) compared to active and early patterns (LTB4, p = 0.0006), and giant capillaries (p = 0.01) showed higher levels of LTs. Levels of pCysLT were higher in patients with RP at examination vs. patients without RP; saCysLT and LTB4 were higher in SSc group with vs. without capillary loss. LTs could be involved in the pathophysiology of vascular abnormalities. Further research is required to determine if blocking LTs could be a therapeutic target for SSc vascular manifestations.

The Functions of Cytochrome P450 ω-hydroxylases and the Associated Eicosanoids in Inflammation-Related Diseases

The cytochrome P450 (CYP) ω-hydroxylases are a subfamily of CYP enzymes. While CYPs are the main metabolic enzymes that mediate the oxidation reactions of many endogenous and exogenous compounds in the human body, CYP ω-hydroxylases mediate the metabolism of multiple fatty acids and their metabolites via the addition of a hydroxyl group to the ω- or (ω-1)-C atom of the substrates. The substrates of CYP ω-hydroxylases include but not limited to arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, epoxyeicosatrienoic acids, leukotrienes, and prostaglandins. The CYP ω-hydroxylases-mediated metabolites, such as 20-hyroxyleicosatrienoic acid (20-HETE), 19-HETE, 20-hydroxyl leukotriene B4 (20-OH-LTB₄), and many ω-hydroxylated prostaglandins, have pleiotropic effects in inflammation and many inflammation-associated diseases. Here we reviewed the classification, tissue distribution of CYP ω-hydroxylases and the role of their hydroxylated metabolites in inflammation-associated diseases. We described up-regulation of CYP ω-hydroxylases may be a pathogenic mechanism of many inflammation-associated diseases and thus CYP ω-hydroxylases may be a therapeutic target for these diseases. CYP ω-hydroxylases-mediated eicosanods play important roles in inflammation as pro-inflammatory or anti-inflammatory mediators, participating in the process stimulated by cytokines and/or the process stimulating the production of multiple cytokines. However, most previous studies focused on 20-HETE,and further studies are needed for the function and mechanisms of other CYP ω-hydroxylases-mediated eicosanoids. We believe that our studies of CYP ω-hydroxylases and their associated eicosanoids will advance the translational and clinal use of CYP ω-hydroxylases inhibitors and activators in many diseases.

Inflammation, It's Regulation and Antiphlogistic Effect of the Cyanogenic Glycoside Amygdalin

The inflammatory reaction accompanies in part or in full any disease process in the vascularized metazoan. This complicated reaction is controlled by regulatory mechanisms, some of which produce unpleasant symptomatic manifestations of inflammation. Therefore, there has been an effort to develop selective drugs aimed at removing pain, fever, or swelling. Gradually, however, serious adverse side effects of such inhibitors became apparent. Scientific research has therefore continued to explore new possibilities, including naturally available substances. Amygdalin is a cyanogenic glycoside present, e.g., in bitter almonds. This glycoside has already sparked many discussions among scientists, especially about its anticancer potential and related toxic cyanides. However, toxicity at different doses made it generally unacceptable. Although amygdalin given at the correct oral dose may not lead to poisoning, it has not yet been accurately quantified, as its action is often affected by different intestinal microbial consortia. Its pharmacological activities have been studied, but its effects on the body's inflammatory response are lacking. This review discusses the chemical structure, toxicity, and current knowledge of the molecular mechanism of amygdalin activity on immune functions, including the anti-inflammatory effect, but also discusses inflammation as such, its mediators with diverse functions, which are usually targeted by drugs.

Advance toward isolation, extraction, metabolism and health benefits of kaempferol, a major dietary flavonoid with future perspectives

As a major ubiquitous secondary metabolite, flavonoids are widely distributed in planta. Among flavonoids, kaempferol is a typical natural flavonol in diets and medicinal plants with myriad bioactivities, such as anti-inflammatory activity, anti-cancer activity, antioxidant activity, and anti-diabetic activity. However, the natural sources, absorption and metabolism as well as the bioactivities of kaempferol have not been reviewed comprehensively and systematically. This review highlights the latest research progress and the effect of kaempferol in the prevention and treatment of various chronic diseases, as well as its protective health effects, and provides a theoretical basis for future research to be used in nutraceuticals. Further, comparison of the different extraction and analytical methods are presented to highlight the most optimum for PG recovery and its detection in plasma and body fluids. Such review aims at improving the value-added applications of this unique dietary bioactive flavonoids at commercial scale and to provide a reference for its needed further development.

Cannabinoids-A New Perspective in Adjuvant Therapy for Pulmonary Hypertension

Currently, no treatment can completely cure pulmonary hypertension (PH), which can lead to right ventricular failure and, consequently, death. Therefore, searching for new therapies remains important. Increased resistance in pulmonary circulation is mainly caused by the excessive contraction and proliferation of small pulmonary arteries. Cannabinoids, a group of lipophilic compounds that all interact with cannabinoid receptors, exert a pulmonary vasodilatory effect through several different mechanisms, including mechanisms that depend on vascular endothelium and/or receptor-based mechanisms, and may also have anti-proliferative and anti-inflammatory properties. The vasodilatory effect is important in regulating pulmonary resistance, which can improve patients’ quality of life. Moreover, experimental studies on the effects of cannabidiol (plant-derived, non-psychoactive cannabinoid) in animal PH models have shown that cannabidiol reduces right ventricular systolic pressure and excessive remodelling and decreases pulmonary vascular hypertrophy and pulmonary vascular resistance. Due to the potentially beneficial effects of cannabinoids on pulmonary circulation and PH, in this work, we review whether cannabinoids can be used as an adjunctive therapy for PH. However, clinical trials are still needed to recommend the use of cannabinoids in the treatment of PH.

Efficacy of therapeutic fasting and plant-based diet in patients with rheumatoid arthritis (NutriFast): study protocol for a randomised controlled clinical trial

BACKGROUND

Previous studies have shown beneficial effects of therapeutic fasting and plant-based dietary interventions on disease activity in patients with rheumatoid arthritis (RA) for a duration of up to 1 year. To date, the effects of such interventions on the gut microbiome and on modern diagnostic markers in patients with RA have not been studied. This trial aims to investigate the clinical effects of therapeutic fasting and a plant-based diet in patients with RA, additionally considering current immunological diagnostic tools and microbiome analyses.

METHODS/DESIGN

This trial is an open-label, single-centre, randomised, controlled, parallel-group clinical trial. We will randomly assign 84 patients with RA under a stable standard therapy to either (1) therapeutic fasting followed by a plant-based dietary intervention or (2) to a conventional nutritional counselling focusing on an anti-inflammatory dietary pattern according to the recommendations of the Deutsche Gesellschaft für Ernährung (German society for nutrition). Primary outcome parameter is the group difference from baseline to 12 weeks on the Health Assessment Questionnaire (HAQ). Other secondary outcomes include established clinical criteria for disease activity and treatment response in RA (Disease Activity Score 28, Simple Disease Activity Index, ACR-Response Criteria), changes in self-reported health and physical functional ability, mood, stress, quality of life, dietary behaviour via 3-day food records and a modified Food Frequency Questionnaire, body composition, changes in the gut microbiome, metabolomics and cytometric parameters. Outcomes will be assessed at baseline and day 7, after 6 weeks, 12 weeks and after 6 months.

ETHICS AND DISSEMINATION

Ethical approval to process and analyse data, and to publish the results was obtained through the institutional review board of Charité-Universitätsmedizin Berlin. Results of this trial will be disseminated through peer-reviewed publications and scientific presentations.

TRIAL REGISTRATION NUMBER

NCT03856190.

Anti-inflammatory and analgesic actions of bufotenine through inhibiting lipid metabolism pathway

Inflammation is a primary defense and immune response. However, under pathological conditions, the inflammation processes always become uncontrolled and lead to chronic diseases. Bufotenine, as a natural component from toad venom, showed great potential for development as a novel anti-inflammation and analgesia agent. This study aimed to investigate the therapeutic effects of bufotenine against inflammation and pain on animal models with a focus on lipid metabolism. In pharmacological studies, bufotenine significantly inhibited the swelling rates on formalin-induced paw edema model, and increased paw withdrawal mechanical thresholds (PWMTs) in von Frey test and thermal pain thresholds (TPTs) in hot-plate test. High-sensitivity lipidomics analysis revealed the effects might be related to the down-regulation of inflammatory mediators from cyclooxygenase (COX), lipoxygenase (LOX), cytochrome P450 (CYP450), linoleic acid (LA), docosahexaenoic acid (DHA) and other pathways. The activities might result from the binding of bufotenine and its receptors, including sigma-1 receptor and 5-Hydroxytryptamine receptor 3A, thus regulating lipid metabolism pathway. The research provided a systemic evidence for the actions and mechanism of bufotenine. It suggested that the natural compound might be a potential candidate for reducing inflammatory pain disorders.

Targeting Mammalian 5-Lipoxygenase by Dietary Phenolics as an Anti-Inflammatory Mechanism: A Systematic Review

5-Lipoxygenase (5-LOX) plays a key role in inflammation through the biosynthesis of leukotrienes and other lipid mediators. Current evidence suggests that dietary (poly)phenols exert a beneficial impact on human health through anti-inflammatory activities. Their mechanisms of action have mostly been associated with the modulation of pro-inflammatory cytokines (TNF-α, IL-1β), prostaglandins (PGE2), and the interaction with NF-κB and cyclooxygenase 2 (COX-2) pathways. Much less is known about the 5-lipoxygenase (5-LOX) pathway as a target of dietary (poly)phenols. This systematic review aimed to summarize how dietary (poly)phenols target the 5-LOX pathway in preclinical and human studies. The number of studies identified is low (5, 24, and 127 human, animal, and cellular studies, respectively) compared to the thousands of studies focusing on the COX-2 pathway. Some (poly)phenolics such as caffeic acid, hydroxytyrosol, resveratrol, curcumin, nordihydroguaiaretic acid (NDGA), and quercetin have been reported to reduce the formation of 5-LOX eicosanoids in vitro. However, the in vivo evidence is inconclusive because of the low number of studies and the difficulty of attributing effects to (poly)phenols. Therefore, increasing the number of studies targeting the 5-LOX pathway would largely expand our knowledge on the anti-inflammatory mechanisms of (poly)phenols.

Beneficial Outcomes of Omega-6 and Omega-3 Polyunsaturated Fatty Acids on Human Health: An Update for 2021

Oxidative stress and inflammation have been recognized as important contributors to the risk of chronic non-communicable diseases. Polyunsaturated fatty acids (PUFAs) may regulate the antioxidant signaling pathway and modulate inflammatory processes. They also influence hepatic lipid metabolism and physiological responses of other organs, including the heart. Longitudinal prospective cohort studies demonstrate that there is an association between moderate intake of the omega-6 PUFA linoleic acid and lower risk of cardiovascular diseases (CVDs), most likely as a result of lower blood cholesterol concentration. Current evidence suggests that increasing intake of arachidonic acid (up to 1500 mg/day) has no adverse effect on platelet aggregation and blood clotting, immune function and markers of inflammation, but may benefit muscle and cognitive performance. Many studies show that higher intakes of omega-3 PUFAs, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are associated with a lower incidence of chronic diseases characterized by elevated inflammation, including CVDs. This is because of the multiple molecular and cellular actions of EPA and DHA. Intervention trials using EPA + DHA indicate benefit on CVD mortality and a significant inverse linear dose-response relationship has been found between EPA + DHA intake and CVD outcomes. In addition to their antioxidant and anti-inflammatory roles, omega-3 fatty acids are considered to regulate platelet homeostasis and lower risk of thrombosis, which together indicate their potential use in COVID-19 therapy.

Perspective: Moving Toward Desirable Linoleic Acid Content in Infant Formula

Infant formula should provide the appropriate nutrients and adequate energy to facilitate healthy infant growth and development. If conclusive data on quantitative nutrient requirements are not available, the composition of human milk (HM) can provide some initial guidance on the infant formula composition. This paper provides a narrative review of the current knowledge, unresolved questions, and future research needs in the area of HM fatty acid (FA) composition, with a particular focus on exploring appropriate intake levels of the essential FA linoleic acid (LA) in infant formula. The paper highlights a clear gap in clinical evidence as to the impact of LA levels in HM or formula on infant outcomes, such as growth, development, and long-term health. The available preclinical information suggests potential disadvantages of high LA intake in the early postnatal period. We recommend performing well-designed clinical intervention trials to create clarity on optimal levels of LA to achieve positive impacts on both short-term growth and development and long-term functional health outcomes.

PPARα agonist WY-14,643 induces adipose atrophy and fails to blunt chronic ethanol-induced hepatic fat accumulation in mice lacking adipose FGFR1

Fibroblast growth factor 21 (FGF21) is mainly regulated by peroxisome proliferator-activated receptor α (PPARα) in liver. The PPARα-FGF21 axis protects against alcohol-related liver disease (ALD). FGF21 exerts its effect via FGF receptor 1 (FGFR1). However, liver specific FGFR1 abrogation had no effect on ALD. Adipose tissues highly express FGFR1. When adipocyte specific FGFR1 knockout (fgfr1^adipoQ-cre) mice and corresponding normal control (fgfr1^fl/fl) mice were fed with Lieber-DeCarli ethanol liquid diet for 3 weeks, liver triglyceride (TG) accumulation was increased in the fgfr1^fl/fl mice to a greater extent than in the fgfr1^adipoQ-cre mice. When PPARα agonist WY-14,643 was added in the liquid ethanol diet at 10 mg/L, the ethanol-induced liver TG accumulation was blunted in the fgfr1^fl/fl mice but not in the fgfr1^adipoQ-cre mice. There was no significant difference in WY-14,643-induced fatty acid oxidation, ethanol metabolism, and oxidative stress between the fgfr1^fl/fl and fgfr1^adipoQ-cre mice. Interestingly, adipose atrophy was induced by WY-14,643 in the fgfr1^adipoQ-cre mice but not in the fgfr1^fl/fl mice. Serum free fatty acid was also decreased by WY-14,643 in the fgfr1^adipoQ-cre mice but not in the fgfr1^fl/fl mice. These results suggest that WY-14,643 inhibits alcoholic fatty liver and regulates adipose tissue mass and fat mobilization from adipose tissues to liver in an adipocyte FGFR1-dependent manner.

Searching for Scientific Explanations for the Uses of Spanish Folk Medicine: A Review on the Case of Mullein (Verbascum, Scrophulariaceae)

Verbascum species (common mullein) have been widely used in Spanish folk medicine to treat pathologies related to the musculature, skeleton, and circulatory, digestive, and respiratory systems, as well as to treat infectious diseases and organ-sense illnesses. These applications support the potential anti-inflammatory action of Verbascum phytochemicals. Based on the aforementioned facts, and following a deep bibliographic review of the chemical composition of the 10 species of Verbascum catalogued by the Spanish Inventory of Traditional Knowledge related to Biodiversity, we look for scientific evidences to correlate the traditional medical uses with the chemical components of these plants. To support these findings, in silico simulations were performed to investigate molecular interactions between Verbascum phytochemicals and cellular components. Most of common mullein traditional uses could rely on the anti-inflammatory action of phytochemicals, such as quercetin, and it could explain the employment of these plants to treat a wide range of diseases mediated by inflammatory processes such as respiratory diseases, otitis, arthrosis, and rheumatism among others.

Targeted analysis of eicosanoids derived from cytochrome P450 pathway by high-resolution multiple-reaction monitoring mass spectrometry

Cytochrome P450 (CYP450) pathway is one of the critical enzymatic via eicosanoid biosynthesis. Nevertheless, their metabolites are far less explored. This pathway plays a crucial role in converting arachidonic acid to hydroxyeicosatetraenoic (HETEs), epoxyeicosatrienoic (EETs), dihydroxyeicosatetraenoic acids (DiHETEs), and dihydroxyeicosatrienoic acids (DiHETrEs), which mediate several physiological and pathological functions. However, CYP450-derived eicosanoids are structurally complex, making those analyses a challenge in lipidomics studies. Herein, a high-resolution multiple-reaction monitoring (MRM^HR ) method has been proposed as a powerful tool for the simultaneous analysis of CYP450-eicosanoids on different biological samples. The developed liquid chromatography (LC)-MRM^HR method was partially validated according to the Food and Drug Administration (FDA) criteria, demonstrating adequate specificity, linearity, precision, and accuracy. Besides, several biological samples were analyzed to guarantee the feasibility of the method. The proposed strategy may improve the understanding of CYP450-derived eicosanoids in biological systems, which could be fundamental to reveal new aspects of those in physiologic and pathologic conditions.

Clarification of Arachidonic Acid Metabolic Pathway Intricacies

Surrounding inflammation activates phospholipase A₂, which cleaves and releases arachidonic acid (ARA) from cell membranes. The four cis double bonds are instrumental in ARA susceptibility to oxidation, resulting in the generation of numerous bioactive metabolites of critical importance for the immune system, namely inflammation in response to pathogens, resolution of inflammation, wound healing, and mood and energy balance. The ARA metabolism steps are replete with intricacies, deterring researchers from identifying targets, which could be useful in modulating the synthesis of ARA metabolites toward exclusive protection of the host from pathogens, endogenous excessive danger signals, pain, inflammation, stress, and anxiety disorders. While ARA metabolic pathways are reasonably defined, it was deemed mandatory to fully clarify the flow and direction of protons, electrons, and oxygen atoms and the intricacies behind formation and breakage of double bonds and cyclic structures. This in-depth novel information will perfect the development of strategies and drugs aimed at counteracting inflammation and promoting healing.

The Role of Prostaglandins in Different Types of Cancer

The prostaglandins constitute a family of lipids of 20 carbon atoms that derive from polyunsaturated fatty acids such as arachidonic acid. Traditionally, prostaglandins have been linked to inflammation, female reproductive cycle, vasodilation, or bronchodilator/bronchoconstriction. Recent studies have highlighted the involvement of these lipids in cancer. In this review, existing information on the prostaglandins associated with different types of cancer and the advances related to the potential use of them in neoplasm therapies have been analyzed. We can conclude that the effect of prostaglandins depends on multiple factors, such as the target tissue, their plasma concentration, and the prostaglandin subtype, among others. Prostaglandin D2 (PGD₂) seems to hinder tumor progression, while prostaglandin E2 (PGE₂) and prostaglandin F2 alpha (PGF_2α) seem to provide greater tumor progression and aggressiveness. However, more studies are needed to determine the role of prostaglandin I2 (PGI₂) and prostaglandin J2 (PGJ₂) in cancer due to the conflicting data obtained. On the other hand, the use of different NSAIDs (non-steroidal anti-inflammatory drugs), especially those selective of COX-2 (cyclooxygenase 2), could have a crucial role in the fight against different neoplasms, either as prophylaxis or as an adjuvant treatment. In addition, multiple targets, related to the action of prostaglandins on the intracellular signaling pathways that are involved in cancer, have been discovered. Thus, in depth research about the prostaglandins involved in different cancer and the different targets modulated by them, as well as their role in the tumor microenvironment and the immune response, is necessary to obtain better therapeutic tools to fight cancer.

Prostaglandin E2 Enhances Gap Junctional Intercellular Communication in Clonal Epithelial Cells

Prostaglandins are a group of lipids that produce diverse physiological and pathological effects. Among them, prostaglandin E2 (PGE2) stands out for the wide variety of functions in which it participates. To date, there is little information about the influence of PGE2 on gap junctional intercellular communication (GJIC) in any type of tissue, including epithelia. In this work, we set out to determine whether PGE2 influences GJIC in epithelial cells (MDCK cells). To this end, we performed dye (Lucifer yellow) transfer assays to compare GJIC of MDCK cells treated with PGE2 and untreated cells. Our results indicated that (1) PGE2 induces a statistically significant increase in GJIC from 100 nM and from 15 min after its addition to the medium, (2) such effect does not require the synthesis of new mRNA or proteins subunits but rather trafficking of subunits already synthesized, and (3) such effect is mediated by the E2 receptor, which, in turn, triggers a signaling pathway that includes activation of adenylyl cyclase and protein kinase A (PKA). These results widen the knowledge regarding modulation of gap junctional intercellular communication by prostaglandins.

Effect of ω-3 Polyunsaturated Fatty Acids-Derived Bioactive Lipids on Metabolic Disorders

Arachidonic acid (ARA) is an important ω-6 polyunsaturated fatty acid (PUFA), and docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and n-3 docosapentaenoic acid (n-3 DPA) are three well-known ω-3 PUFAs. These fatty acids can be metabolized into a number of bioactive lipids. Eicosanoids derived from ARA have drawn great attention because of their important and complex biofunctions. Although EPA, DHA and n-3 DPA have also shown powerful biofunctions, we have fewer studies of metabolites derived from them than those from ARA. Recently, growing research has focused on the bioaction of ω-3 PUFA-derived metabolites, which indicates their great potential for treating metabolic disorders. Most of the functional studies of these bioactive lipids focused on their anti-inflammatory effects. However, several studies elucidated their direct effects on pancreatic β cells, hepatocytes, adipocytes, skeletal muscle cells, and endothelial cells. These researches revealed the importance of studying the functions of metabolites derived from ω-3 polyunsaturated fatty acids other than themselves. The current review summarizes research into the effects of ω-3 PUFA-derived oxylipins on metabolic disorders, including diabetes, non-alcoholic fatty liver disease, adipose tissue dysfunction, and atherosclerosis.

Beneficial Modulation of Lipid Mediator Biosynthesis in Innate Immune Cells by Antirheumatic Tripterygium wilfordii Glycosides

Tripterygium wilfordii glycosides (TWG) is a traditional Chinese medicine with effectiveness against rheumatoid arthritis (RA), supported by numerous clinical trials. Lipid mediators (LM) are biomolecules produced from polyunsaturated fatty acids mainly by cyclooxygenases (COX) and lipoxygenases (LOX) in complex networks which regulate inflammation and immune responses and are strongly linked to RA. The mechanism by which TWG affects LM networks in RA treatment remains elusive. Employing LM metabololipidomics using ultra-performance liquid chromatography-tandem mass spectrometry revealed striking modulation of LM pathways by TWG in human monocyte-derived macrophage (MDM) phenotypes. In inflammatory M1-MDM, TWG (30 µg/mL) potently suppressed agonist-induced formation of 5-LOX products which was confirmed in human PMNL and traced back to direct inhibition of 5-LOX (IC₅₀ = 2.9 µg/mL). TWG also efficiently blocked thromboxane formation in M1-MDM without inhibiting other prostanoids and COX enzymes. Importantly, in anti-inflammatory M2-MDM, TWG (30 µg/mL) induced pronounced formation of specialized pro-resolving mediators (SPM) and related 12/15-LOX-derived SPM precursors, without COX and 5-LOX activation. During MDM polarization, TWG (1 µg/mL) decreased the capacity to generate pro-inflammatory 5-LOX and COX products, cytokines and markers for M1 phenotypes. Together, suppression of pro-inflammatory LM but SPM induction may contribute to the antirheumatic properties of TWG.

A review of the functional effects of pine nut oil, pinolenic acid and its derivative eicosatrienoic acid and their potential health benefits

Pine nut oil (PNO) is rich in a variety of unusual delta-5-non-methylene-interrupted fatty acids (NMIFAs), including pinolenic acid (PLA; all cis-5,-9,-12 18:3) which typically comprises 14 to 19% of total fatty acids. PLA has been shown to be metabolised to eicosatrienoic acid (ETA; all cis-7,-11,-14 20:3) in various cells and tissues. Here we review the literature on PNO, PLA and its metabolite ETA in the context of human health applications. PNO and PLA have a range of favourable effects on body weight as well as fat deposition through increased energy expenditure (fatty acid oxidation) and decreased food energy intake (reduced appetite). PNO and PLA improve blood and hepatic lipids in animal models and insulin sensitivity in vitro and reduce inflammation and modulate immune function in vitro and in animal models. The few studies which have examined effects of ETA indicate it has anti-inflammatory properties. Another NMIFA from PNO, sciadonic acid (all cis-5,-11,-14 20:3), has generally similar properties to PLA where these have been investigated. There is potential for human health benefits from PNO, its constituent NMIFA PLA and the PLA derivative ETA. However further studies are needed to explore the effects in humans.

Long-Chain Polyunsaturated Fatty Acids (LCPUFAs) and the Developing Immune System: A Narrative Review

The immune system is complex: it involves many cell types and numerous chemical mediators. An immature immune response increases susceptibility to infection, whilst imbalances amongst immune components leading to loss of tolerance can result in immune-mediated diseases including food allergies. Babies are born with an immature immune response. The immune system develops in early life and breast feeding promotes immune maturation and protects against infections and may protect against allergies. The long-chain polyunsaturated fatty acids (LCPUFAs) arachidonic acid (AA) and docosahexaenoic acid (DHA) are considered to be important components of breast milk. AA, eicosapentaenoic acid (EPA) and DHA are also present in the membranes of cells of the immune system and act through multiple interacting mechanisms to influence immune function. The effects of AA and of mediators derived from AA are often different from the effects of the n-3 LCPUFAs (i.e., EPA and DHA) and of mediators derived from them. Studies of supplemental n-3 LCPUFAs in pregnant women show some effects on cord blood immune cells and their responses. These studies also demonstrate reduced sensitisation of infants to egg, reduced risk and severity of atopic dermatitis in the first year of life, and reduced persistent wheeze and asthma at ages 3 to 5 years, especially in children of mothers with low habitual intake of n-3 LCPUFAs. Immune markers in preterm and term infants fed formula with AA and DHA were similar to those in infants fed human milk, whereas those in infants fed formula without LCPUFAs were not. Infants who received formula plus LCPUFAs (both AA and DHA) showed a reduced risk of allergic disease and respiratory illness than infants who received standard formula. Studies in which infants received n-3 LCPUFAs report immune differences from controls that suggest better immune maturation and they show lower risk of allergic disease and respiratory illness over the first years of life. Taken together, these findings suggest that LCPUFAs play a role in immune development that is of clinical significance, particularly with regard to allergic sensitisation and allergic manifestations including wheeze and asthma.

Expert Opinion on Benefits of Long-Chain Omega-3 Fatty Acids (DHA and EPA) in Aging and Clinical Nutrition

Life expectancy is increasing and so is the prevalence of age-related non-communicable diseases (NCDs). Consequently, older people and patients present with multi-morbidities and more complex needs, putting significant pressure on healthcare systems. Effective nutrition interventions could be an important tool to address patient needs, improve clinical outcomes and reduce healthcare costs. Inflammation plays a central role in NCDs, so targeting it is relevant to disease prevention and treatment. The long-chain omega-3 polyunsaturated fatty acids (omega-3 LCPUFAs) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are known to reduce inflammation and promote its resolution, suggesting a beneficial role in various therapeutic areas. An expert group reviewed the data on omega-3 LCPUFAs in specific patient populations and medical conditions. Evidence for benefits in cognitive health, age- and disease-related decline in muscle mass, cancer treatment, surgical patients and critical illness was identified. Use of DHA and EPA in some conditions is already included in some relevant guidelines. However, it is important to note that data on the effects of omega-3 LCPUFAs are still inconsistent in many areas (e.g., cognitive decline) due to a range of factors that vary amongst the trials performed to date; these factors include dose, timing and duration; baseline omega-3 LCPUFA status; and intake of other nutrients. Well-designed intervention studies are required to optimize the effects of DHA and EPA in specific patient populations and to develop more personalized strategies for their use.