Protectins and maresins: New pro-resolving families of mediators in acute inflammation and resolution bioactive metabolome

Specialized Pro-Resolving Mediators as Emerging Players in Cardioprotection: From Inflammation Resolution to Therapeutic Potential

AIM

Timely myocardial reperfusion is essential for restoring blood flow to post-ischemic tissue, thereby reducing cardiac injury and limiting infarct size. However, this process can paradoxically result in additional, irreversible myocardial damage, known as myocardial ischemia-reperfusion injury (MIRI). The goal of this review is to explore the role of specialized pro-resolving mediators (SPMs) in atherosclerosis and MIRI, and to assess the therapeutic potential of targeting inflammation resolution in these cardiovascular conditions.

METHODS

This review summarizes current preclinical and clinical evidence on the involvement of SPMs in the pathogenesis of atherosclerosis and MIRI, acknowledging that several cellular and molecular aspects of their mechanisms of action remain to be fully elucidated.

RESULTS

MIRI is a complex phenomenon in which inflammation, initially triggered during ischemia and further amplified upon reperfusion, plays a central role in its pathogenesis. Various cellular and molecular players mediate the initial pro-inflammatory response and the subsequent anti-inflammatory reparative phase following acute myocardial infarction (AMI), contributing both to ischemia- and reperfusion-induced damage as well as to the healing process. SPMs have emerged as key endogenous immunoresolvents with potent anti-inflammatory, antioxidant, and pro-resolving properties that contribute to limit excessive acute inflammation and promote tissue repair. While dysregulated SPM-related signaling has been linked to various cardiovascular diseases (CVD), their precise role in AMI and MIRI remains incompletely understood.

CONCLUSION

Targeting inflammation resolution may represent a promising therapeutic strategy for mitigating atheroprogression and addressing a complex condition such as MIRI.

Lack of effects of Resolvin D1 after spinal cord injury in mice

Inflammation is a fundamental component of the body's response to injury or infection and is responsible for restoring tissue homeostasis and starting the wound healing process. To avoid excessive tissue damage, it is important to efficiently resolve inflammation once it is no longer necessary. In recent years, the discovery of pro-resolving lipid mediators derived from polyunsaturated fatty acids, such as Resolvin D1 (RvD1), has shed light on the resolution of inflammation. However, the impact of RvD1 on Spinal Cord Injury (SCI) remains unexplored. In this study, we provide direct evidence that the administration of RvD1 for one week after SCI fails to enhance resolution of inflammation and does not improve functional and histological outcomes. Our transcriptomic analysis reveals that RvD1 does not modulate inflammatory response pathways in the injured spinal cord but leads to significant changes in the expression of genes related to ribosomal function and extracellular matrix pathways. Unlike SCI, RvD1 treatment ameliorated neurological deficits in experimental autoimmune encephalomyelitis. Our findings represent the first report demonstrating that RvD1 treatment does not exert therapeutic actions in the context of SCI and suggest that this pro-resolving agonist may exert therapeutic actions in certain but not in all conditions involving an inflammatory component.

Exploring the unique role of specialized pro-resolving mediators in cancer therapeutics

Unresolved chronic inflammation, a hallmark of cancer, promotes tumor growth and metastasis in various cancer types. In contrast to blocking inflammation, stimulation of resolution of inflammation is an entirely novel approach to "resolve" inflammation. Resolution of inflammation mechanisms in cancer includes clearance of tumor debris, counter-regulation of pro-inflammatory eicosanoids and cytokines, and suppression of leukocyte infiltration. Conventional cytotoxic chemotherapy, radiation, anti-angiogenic therapy, and immune checkpoint inhibitors directly or indirectly can lead to the generation of pro-tumorigenic cellular debris. Over the past two decades, a potential paradigm shift has emerged in the inflammation field with the discovery of specialized pro-resolving mediators (SPMs), including resolvins, lipoxins, maresins, and protectins. SPMs are structurally distinct families of mediators grouped together by their pro-resolving "debris-clearing" functions. "Pro-resolving" therapies are in clinical development for various inflammation-driven diseases, including cancer. SPMs, as novel cancer therapeutics, have tremendous potential to enhance current cancer therapy. The mechanisms of SPMs as anti-cancer therapeutics are under active investigation by various laboratories worldwide. Here, we explore the current appreciation of the SPMs as innovative potential treatments designed to harness the unique anti-cancer activity of SPMs.

Specialized Pro-Resolving Lipid Mediators in Pulmonary Diseases: Molecular and Therapeutic Implications

Inflammatory lung diseases (ILDs) represent a global public health crisis characterized by escalating prevalence, significant morbidity, and substantial mortality. In response to the complex immunopathogenic mechanisms driving these conditions, novel pharmacological strategies targeting resolution pathways have emerged throughout the discovery of specialized pro-resolving lipid mediator (SPM; resolvins, maresins, and protectins) dysregulation across the ILD spectra, positioning these endogenous molecules as promising therapeutic candidates for modulating maladaptive inflammation and promoting tissue repair. Over the past decade, this paradigm has catalyzed extensive translational research into SPM-based interventions as precision therapeutics for respiratory inflammation. In asthma, they reduce mucus hypersecretion, bronchial hyperreactivity, and airway inflammation, with prenatal SPM exposure potentially lowering offspring disease risk. In COPD, SPMs attenuate amyloid A-driven inflammation, normalizing cytokine/chemokine imbalances and oxidative stress and mitigating COVID-19-associated cytokine storm, enhancing survival. This review synthesizes SPMs' pharmacotherapeutic mechanisms in ILDs and evaluates current preclinical and clinical evidence.

The effect of perinatal supplementation of DHA on specialized pro-resolving lipid mediators in the brain of offspring

The perinatal period is crucial for fetal neurological development, relying on omega-3 polyunsaturated fatty acids (PUFAs) for essential processes. Omega-3 PUFA, including docosahexaenoic acid (DHA), are precursors to a novel class of bioactive metabolites called specialized pro-resolving mediators (SPMs), which have been suggested to have a dual purpose in mitigating neuroinflammation while simultaneously supporting cognitive outcomes, implicating a role in offspring neurodevelopment. DHA is evidenced for its role in early brain development, but the underlying mechanism it exerts its cognitive benefits remain unclear. Pregnant sows were fed a control diet (CON; n = 6) or a diet with DHA (n = 6, 75 mg DHA/kg BW/day) from gestation through lactation. At weaning, piglets (n = 2/sow) underwent resting state-functional magnetic resonance imaging (rs-fMRI) to assess brain functional activation. Subsequently, brain tissue from prefrontal cortex, cerebellum, and hippocampus were collected from piglets. Tissue DHA and eicosapentaenoic acid (EPA)-derived SPMs were quantified using LC-MS. Levels of SPMs were higher in the brains of piglets from DHA-fed sows, particularly in the prefrontal cortex and cerebellum, compared to control piglets. Additionally, a distinct association of several prefrontal SPMs with activation of the cerebellar functional network was marked in the piglet offspring. The findings highlight a potential for SPMs to function as mediators for neurodevelopmental programming, through contributing to inflammation resolution and neuronal connectivity. This work underscores the importance of maternal nutrition in shaping offspring brain health and lays the groundwork for targeted interventions leveraging the benefits of DHA and its bioactive metabolites.

Immunomodulatory Effects of Omega-3 Fatty Acids: Mechanistic Insights and Health Implications

Omega-3 fatty acids play a significant role in immunomodulation, with nutrigenomic approaches highlighting their impact on gene expression related to immune responses. Research indicates that omega-3 fatty acids can modulate inflammatory pathways, potentially reducing chronic inflammation and enhancing immune function. This review discusses the intersection of nutrigenomics and nutriepigenomics, focusing on how omega-3 fatty acids influence gene expression, immune function, and overall health. The immune system is a complex network responsible for defending the body against pathogens and maintaining internal balance. Comprised of innate and adaptive immunity, the system involves various cells, tissues, and organs working together to combat infections and prevent diseases. Omega-3 polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play a significant role in modulating the immune system. These fatty acids influence immune cell function, membrane fluidity, and signaling processes, enhancing immune responses and reducing inflammation. Furthermore, EPA and DHA affect several signaling pathways, reducing the expression of proinflammatory cytokines and inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation, a critical transcription factor in the inflammatory response. Additionally, they activate PPAR-γ, further diminishing inflammatory gene expression. As precursors to specialized proresolving lipid mediators, EPA and DHA help shift the lipid mediator profile from proinflammatory to antiinflammatory derivatives, thus aiding in the resolution of inflammation.

Microalgae as an emerging alternative raw material of docosahexaenoic acid and eicosapentaenoic acid - a review

Long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been widely applied due to their nutraceutical and healthcare benefits. With the rising rates of chronic diseases, there is a growing consumer interest and demand for sustainable dietary sources of n-3 PUFAs. Currently, microalgae have emerged as a sustainable source of n-3 PUFAs which are rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), regarded as promising alternatives to conventional sources (seafood) that cannot meet the growing demands of natural food supplements. This review provides a comprehensive overview of recent advancements in strategies such as genetic engineering, mutagenesis, improving photosynthetic efficiency, nutritional or environmental factors, and cultivation approaches to improve DHA and EPA production efficiency in microalgae cells. Additionally, it explains the application of DHA and EPA-rich microalgae in animal feed, human nutrition- snacks, and supplements to avoid malnutrition and non-communicable diseases.

Fatty acid metabolism in the placentae of gestational diabetes mellitus

The prevalence of gestational diabetes mellitus (GDM), a metabolic complication during pregnancy is increasing rapidly. It exerts various short and long term effects on the mother and the child. Nonetheless, the mechanisms underlying the pathophysiology of GDM are still not clear. Placenta is a key 'programming' agent and any impairment in placental structure and function may hamper the fetal growth and development. Omega-3 and omega-6 fatty acids are key nutrients involved in placental and fetal development. The fatty acids transport from maternal circulation towards the fetus depends on the fatty acid status of the mother, fatty acid metabolism of the placenta and placental transport of fatty acids. Alteration in any of these could influence the fatty acids transport towards the fetus thereby affecting the fetal brain development and leading to impairment in cognitive function in the off-spring. We propose a role for placental fatty acid metabolism in influencing fetal growth and development which in turn can have an impact on cognitive development of the offspring born to GDM women.

Essential fatty acid deficiency in parenteral nutrition: Historical perspective and modern solutions, a narrative review

Essential fatty acid deficiency (EFAD) may occur in the setting of inadequate fat intake, malabsorption, malnutrition, and altered fat metabolism. Humans lack the enzymes to synthesize the essential acids linoleic acid and alpha-linolenic acid, so they must be obtained from the diet. Patients dependent on parenteral nutrition need adequate amounts of these essential fatty acids supplied in lipid injectable emulsions (ILEs). With the increasing use of multicomponent ILEs that are lower in linoleic and alpha-linolenic acid, it is imperative that clinicians understand appropriate dosing to prevent EFAD. An understanding of fatty acid composition and metabolic pathways is important, as the use of the Holman Index (triene:tetraene ratio) alone may lead to an inaccurate diagnosis of EFAD.

Emerging mechanisms of organ crosstalk: The role of oxylipins

There is growing interest in the role of oxylipins in the pathophysiology of several diseases. This is accompanied by a limited but evolving evidence base describing augmented oxylipin concentrations in a range of complications including cardiovascular disease, obesity, liver disease and neurological disorders. Despite this, literature describing oxylipin profiles in blood and multiple organs is inconsistent and the mechanisms by which these profiles are altered, and the relationships between localised tissue and circulating oxylipins are poorly understood. Inflammation and immune response associated with disease requires communication across organs and physiological systems. For example, inflammation and comorbidities associated with obesity extend beyond the adipose tissue and affect the vascular, hepatobiliary and digestive systems amongst others. Communication between organs and physiological systems is implicated in the progression of disease as well as the maintenance of homeostasis. There is emerging evidence for the role of oxylipins as a mechanism of communication in organ crosstalk but the role of these in orchestrating multiple organ and system responses is poorly understood. Herein, we review evidence to support and describe the role of oxylipins in organ crosstalk via the cardiosplenic and gut-link axis. In addition, we review emerging mechanisms of oxylipin regulation, the gut microbiome and modification using nutritional intervention. Finally, we describe future perspectives for addressing challenges in measurement and interpretation of oxylipin research with focus on the host genome as a modifier of oxylipin profiles and response to dietary lipid intervention.

Proresolving Lipid Mediators in the Respiratory System

Lung inflammation, infection, and injury can lead to critical illness and death. The current means to pharmacologically treat excessive uncontrolled lung inflammation needs improvement because many treatments are or will become immunosuppressive. The inflammatory response evolved to protect the host from microbes, injury, and environmental insults. This response brings phagocytes from the bloodstream to the tissue site to phagocytize and neutralize bacterial invaders and enables airway antimicrobial functions. This physiologic response is ideally self-limited with initiation and resolution phases. Polyunsaturated essential fatty acids are precursors to potent molecules that govern both phases. In the initiation phase, arachidonic acid is converted to prostaglandins and leukotrienes that activate leukocytes to transmigrate from postcapillary venules. The omega-3 fatty acids (e.g., DHA and EPA) are precursors to resolvins, protectins, and maresins, which are families of chemically distinct mediators with potent functions in resolution of acute and chronic inflammation in the respiratory system.

Synthesis, characterization and biological profile of some new dihydropyrimidinone derivaties

Objective

The rise of drug-resistant bacteria, viruses, and fungi has prompted the search for new drugs without cross-resistance to current treatments. As a result, the aim of this research was to synthesize various types of dihydropyrimidinones heterocyclic compounds and screened them for their antibiotic properties.

Methodology

Newly synthesized dihydropyrimidinone derivatives were characterized spectroscopically using proton NMR (1HNMR), and FT-IR. These substances were then subjected to molecular docking studies via Auto dock Vina software to determine their affinity for binding to proteins from different bacterial strains including (Staphylococcus epidermidis (S. epidermidis), Staphylococcus aureus (S. aureus), Mycobacterium luteus (M. luteus), Salmonella typhi (S.typhi), Bacillus subtilis (B. subtilis), and Escherichia coli (E. coli) and fungal (Candida glabrata (C. glabrata), Candida albicans (C. albicans), and Saccharomyces cerevisiae (S. cerevisiae) strains. Also in-vitro anti-fungal, anti-bacterial and anti-oxidant activity was performed by using ager well diffusion method and DPPH assay respectively. Moreover, the In-vivo biological evaluation of these derivatives was conducted by using carrageenan-induced hind paw model. The cytotoxicity profile of the synthesized derivatives was done via in-vitro MTT assay.

Results

All newly synthesized derivatives were confirmed via the multiple spectroscopic analysis techniques. All derivatives showed good binding affinities against the multiple targeted protein with. Compound 4c exhibited hightest potential with -10 kcal/mol against bacterial strains. 4b showed best antifungal potential with -10.8 kcal/mol binding affinities. For Bacillus subtilis compound 4b and 4c performed best with 17 mm ± 2.21. for anti-fungal activity against Candida glabrata, amongst the five newly formed compounds, 4a showed best activity with 19 mm ± 1.22 The analogue 4b exhibited best anti-oxidant potential with 63.85 ± 1.39. Compound 4a and 4b showed highest anti-inflammatory potential with 1.011 mm ± 0.247 mg/kg and 1.447 ± 0.212 mg/kg in countering inflammation by targeting toll-like receptor activation and reduce the inflammation in hind paw edema. The selected derivatives exhibited no toxicity profile with 99 % and 98 % cell survival rate using compound 4a and 4b.

Conclusion

Research has been done on the multiple biological activities of dihydropyrimidinones derivatives but the innovation on MDR is still pending. New dihydropyrimidinone derivatives were developed as agents to combat drug resistance. The results of these studies showed that newly synthesized dihydropyrimidinone derivatives are remarkably effective not only as anti-biotic agents but also counter inflammation caused by carrageenan resulting from the activation of the Toll-like receptors (TLRs) signaling pathway along with the non-toxic effect. So it is concluded that the recently synthesized new dihyropyrimidinone derivatives are highly effective antimicrobial derivatives with non-toxic effects on human cell lines.

Lipid-mediated resolution of inflammation and survival in amyotrophic lateral sclerosis

Neuroinflammation impacts on the progression of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. Specialized pro-resolving mediators trigger the resolution of inflammation. We investigate the specialized pro-resolving mediator blood profile and their receptors' expression in peripheral blood mononuclear cells in relation to survival in ALS. People living with ALS (pwALS) were stratified based on bulbar versus limb onset and on key progression metrics using a latent class model, to separate faster progressing from slower progressing ALS. Specialized pro-resolving mediator blood concentrations were measured at baseline and in one additional visit in 20 pwALS and 10 non-neurological controls (Cohort 1). Flow cytometry was used to study the GPR32 and GPR18 resolvin receptors' expression in peripheral blood mononuclear cells from 40 pwALS and 20 non-neurological controls (Cohort 2) at baseline and in two additional visits in 17 pwALS. Survival analysis was performed using Cox proportional hazards models, including known clinical predictors and GPR32 and GPR18 mononuclear cell expression. Differential expression and linear discriminant analyses showed that plasma resolvins were able to distinguish phenotypic variants of ALS from non-neurological controls. RvE3 was elevated in blood from pwALS, whilst RvD1, RvE3, RvT4 and RvD1n-3 DPA were upregulated in A-S and RvD2 in A-F. Compared to non-neurological controls, GPR32 was upregulated in monocytes expressing the active inflammation-suppressing CD11b+ integrin from fast-progressing pwALS, including those with bulbar onset disease (P < 0.0024), whilst GPR32 and GPR18 were downregulated in most B and T cell subtypes. Only GPR18 was upregulated in naïve double positive Tregs, memory cytotoxic Tregs, senescent late memory B cells and late senescent CD8+ T cells from pwALS compared to non-neurological controls (P < 0.0431). Higher GPR32 and GPR18 median expression in blood mononuclear cells was associated with longer survival, with GPR32 expression in classical monocytes (hazard ratio: 0.11, P = 0.003) and unswitched memory B cells (hazard ratio: 0.44, P = 0.008) showing the most significant association, along with known clinical predictors. Low levels of resolvins and downregulation of their membrane receptors in blood mononuclear cells are linked to a faster progression of ALS. Higher mononuclear cell expression of resolvin receptors is a predictor of longer survival. These findings suggest a lipid-mediated neuroprotective response that could be harnessed to develop novel therapeutic strategies and biomarkers for ALS.

The profile of oxidative stress markers (arachidonic and linoleic acid derivatives) in patients with benign prostatic hyperplasia in relation to metabolic syndrome

So far, it has been proven that benign prostatic hyperplasia (BPH) is strongly associated with inflammation resulting from, i.a. the presence of infectious agent, autoimmune disease, aging process and lipid disorders associated with metabolic syndrome (MetS). We analyzed the association between serum eicosanoides (HETE, HODE, lipoxins, prostaglandin, and leucotrien) in aging man with benign prostatic hyperplasia (BPH) and healthy controls. The study involved 219 men (with BPH, n = 144; healthy controls, n = 75). We assessed the content arachidonic and linoleic acid derivatives in the serum samples of the study participants using liquid chromatography (HPLC). The levels of: RvE1 (p < 0.001); LXA4 5S,6R,15R (p = 0.001); 10S,17R-DiDHA (p < 0.001); MaR1 (p = 0.002); 9S-HODE (p < 0.05); 15S-HETE (p < 0.05); 12S-HETE (p < 0.001); 5-oxoETE (p < 0.05) and 5-HETE (p < 0.001) were significantly higher in patients with BPH than in the control group. PGE2 (p = 0.007), LTB4 (p < 0.001), and 18RS-HEPE (p < 0.001) were significantly higher in control group. We also analyzed the relationship between LXA4 5S,6R,15R serum levels of oxidative stress markers and concomitance of MetS. We noticed a relationship between levels and MetS (F1216 = 6.114965, p = 0.01). Our research results suggest that pro-inflammatory mediators and suppressors of inflammation are involved in the development of BPH, but their exact contribution has yet to be investigated.

The Cardioprotective Effects of Polyunsaturated Fatty Acids Depends on the Balance Between Their Anti- and Pro-Oxidative Properties

Polyunsaturated fatty acids (PUFAs) are not only structural components of membrane phospholipids and energy storage molecules in cells. PUFAs are important factors that regulate various biological functions, including inflammation, oxidation, and immunity. Both n-3 and n-6 PUFAs from cell membranes can be metabolized into pro-inflammatory and anti-inflammatory metabolites that, in turn, influence cardiovascular health in humans. The role that PUFAs play in organisms depends primarily on their structure, quantity, and the availability of enzymes responsible for their metabolism. n-3 PUFAs, such as eicosapentaenoic (EPA) and docosahexaenoic (DHA), are generally known for anti-inflammatory and atheroprotective properties. On the other hand, n-6 FAs, such as arachidonic acid (AA), are precursors of lipid mediators that display mostly pro-inflammatory properties and may attenuate the efficacy of n-3 by competition for the same enzymes. However, a completely different light on the role of PUFAs was shed due to studies on the influence of PUFAs on new-onset atrial fibrillation. This review analyzes the role of PUFAs and PUFA derivatives in health-related effects, considering both confirmed benefits and newly arising controversies.

Specialized pro-resolving mediators in vascular inflammation and atherosclerotic cardiovascular disease

Timely resolution of the acute inflammatory response (or inflammation resolution) is an active, highly coordinated process that is essential to optimal health. Inflammation resolution is regulated by specific endogenous signalling molecules that function as 'stop signals' to terminate the inflammatory response when it is no longer needed; to actively promote healing, regeneration and tissue repair; and to limit pain. Specialized pro-resolving mediators are a superfamily of signalling molecules that initiate anti-inflammatory and pro-resolving actions. Without an effective and timely resolution response, inflammation can become chronic, a pathological state that is associated with many widely occurring human diseases, including atherosclerotic cardiovascular disease. Uncovering the mechanisms of inflammation resolution failure in cardiovascular diseases and identifying useful biomarkers for non-resolving inflammation are unmet needs. In this Review, we discuss the accumulating evidence that supports the role of non-resolving inflammation in atherosclerosis and the use of specialized pro-resolving mediators as therapeutic tools for the treatment of atherosclerotic cardiovascular disease. We highlight open questions about therapeutic strategies and mechanisms of disease to provide a framework for future studies on the prevention and treatment of atherosclerosis.

Protective Role of Eicosapentaenoic and Docosahexaenoic and Their N-Ethanolamide Derivatives in Olfactory Glial Cells Affected by Lipopolysaccharide-Induced Neuroinflammation

Neuroinflammation is a symptom of different neurodegenerative diseases, and growing interest is directed towards active drug development for the reduction of its negative effects. The anti-inflammatory activity of polyunsaturated fatty acids, eicosapentaenoic (EPA), docosahexaenoic (DHA), and their amide derivatives was largely investigated on some neural cells. Herein, we aimed to elucidate the protective role of both EPA and DHA and the corresponding N-ethanolamides EPA-EA and DHA-EA on neonatal mouse Olfactory Ensheathing Cells (OECs) after exposition to lipopolysaccharide (LPS)-induced neuroinflammation. To verify their anti-inflammatory effect and cell morphological features on OECs, the expression of IL-10 cytokine, and cytoskeletal proteins (vimentin and GFAP) was evaluated by immunocytochemical procedures. In addition, MTT assays, TUNEL, and mitochondrial health tests were carried out to assess their protective effects on OEC viability. Our results highlight a reduction in GFAP and vimentin expression in OECs exposed to LPS and treated with EPA or DHA or EPA-EA or DHA-EA in comparison with OECs exposed to LPS alone. We observed a protective role of EPA and DHA on cell morphology, while the amides EPA-EA and DHA-EA mainly exerted a superior anti-inflammatory effect compared to free acids.

Development and Validation of Methodologies for the Identification of Specialized Pro-Resolving Lipid Mediators and Classic Eicosanoids in Biological Matrices

Lipid mediators, which include specialized pro-resolving mediators and classic eicosanoids, are pivotal in both initiating and resolving inflammation. The regulation of these molecules determines whether inflammation resolves naturally or persists. However, our understanding of how these mediators are regulated over time in various inflammatory contexts is limited. This gap hinders our grasp of the mechanisms underlying the disease onset and progression. Due to their localized action and low endogenous levels in many tissues, developing robust and highly sensitive methodologies is imperative for assessing their endogenous regulation in diverse inflammatory settings. These methodologies will help us gain insight into their physiological roles. Here, we establish methodologies for extracting, identifying, and quantifying these mediators. Using our methods, we identified a total of 37 lipid mediators. Additionally, by employing a reverse-phase HPLC method, we successfully separated both double-bond and chiral isomers of select lipid mediators, including Lipoxin (LX) A4, 15-epi-LXA4, Protectin (PD) D1, PDX, and 17R-PD1. Validation of the method was performed in both solvent and surrogate matrix for linearity of the standard curves, lower limits of quantitation (LLOQ), accuracy, and precision. Results from these studies demonstrated that linearity was good with r2 values > 0.98, and LLOQ for the mediators ranged from 0.01 to 0.9 pg in phase and from 0.1 to 8.5 pg in surrogate matrix. The relative standard deviation (RSD) for inter- and intraday precision in solvent ranged from 5% to 12% at low, intermediate, and high concentrations, whereas the RSD for the inter- and intraday variability in the accuracy ranged from 95% to 87% at low to high concentrations. The recovery in biological matrices (plasma and serum) for the internal standards used ranged from 60% to 118%. We observed a marked ion suppression for molecules evaluated in negative ionization mode, while there was an ion enhancement effect by the matrix for molecules evaluated in positive ionization mode. Comparison of the integration algorithms, namely, AutoPeak and MQ4, and approaches for calculating signal-to-noise ratios (i.e., US Pharmacopeia, relative noise, peak to peak, and standard deviation) demonstrated that different integration algorithms tested had little influence on signal-to-noise ratio calculations. In contrast, the method used to calculate the signal-to-noise ratio had a more significant effect on the results, with the relative noise approach proving to be the most robust. The methods described herein provide a platform to study the SPM and classic eicosanoids in biological tissues that will help further our understanding of disease mechanisms.

Pro-Resolving Inflammatory Effects of a Marine Oil Enriched in Specialized Pro-Resolving Mediators (SPMs) Supplement and Its Implication in Patients with Post-COVID Syndrome (PCS)

OBJECTIVES

This study aimed to evaluate the eicosanoid and pro-resolutive parameters in patients with Post-COVID Syndrome (PCS) during a 12-week supplementation with a marine oil enriched in specialized pro-resolving mediators (SPMs).

PATIENT AND METHODS

This study was conducted on 53 adult patients with PCS. The subjects included must have had a positive COVID-19 test (PCR, fast antigen test, or serologic test) and persistent symptoms related to COVID-19 at least 12 weeks before their enrolment in the study. The following parameters were evaluated: polyunsaturated fatty acids EPA, DHA, ARA, and DPA; specialized pro-resolving mediators (SPMs), 17-HDHA, 18-HEPE, 14-HDHA, resolvins, maresins, protectins, and lipoxins. The eicosanoids group included prostaglandins, thromboxanes, and leukotrienes. The development of the clinical symptoms of fatigue and dyspnea were evaluated using the Fatigue Severity Scale (FSS) and the Modified Medical Research Council (mMRC) Dyspnea Scale. Three groups with different intake amounts were evaluated (daily use of 500 mg, 1500 mg, and 3000 mg) and compared to a control group not using the product.

RESULTS

In the serum from patients with PCS, an increase in 17-HDHA, 18-HEPE, and 14-HDHA could be observed, and a decrease in the ratio between the pro-inflammatory and pro-resolutive lipid mediators was detected; both differences were significant (p < 0.05). There were no differences found between the three treatment groups. Fatigue and dyspnea showed a trend of improvement after supplementation in all groups.

CONCLUSIONS

A clear enrichment in the serum of the three monohydroxylated SPMs could be observed at a dosage of 500 mg per day. Similarly, a clear improvement in fatigue and dyspnea was observed with this dosage.

Protective Effects of 7S,15R-Dihydroxy-16S,17S-Epoxy-Docosapentaenoic Acid (diHEP-DPA) against Blue Light-Induced Retinal Damages in A2E-Laden ARPE-19 Cells

The purpose of this study was to investigate the protective effects of 7S,15R-dihydroxy-16S,17S-epoxy-docosapentaenoic acid (diHEP-DPA) in retinal pigment epithelial (RPE) cell damage. ARPE-19 cells, a human RPE cell line, were cultured with diHEP-DPA and Bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E), followed by exposure to BL. Cell viability and cell death rates were determined. Western blotting was performed to determine changes in apoptotic factors, mitogen-activated protein kinase (MAPK) family proteins, inflammatory proteins, and oxidative and carbonyl stresses. The levels of pro-inflammatory cytokines in the culture medium supernatants were also measured. Exposure to A2E and BL increased the ARPE-19 cell death rate, which was alleviated by diHEP-DPA in a concentration-dependent manner. A2E and BL treatments induced apoptosis in ARPE-19 cells, which was also alleviated by diHEP-DPA. Analysis of the relationship with MAPK proteins revealed that the expression of p-JNK and p-P38 increased after A2E and BL treatments and decreased with exposure to diHEP-DPA in a concentration-dependent manner. DiHEP-DPA also affected the inflammatory response by suppressing the expression of inflammatory proteins and the production of pro-inflammatory cytokines. Furthermore, it was shown that diHEP-DPA regulated the proteins related to oxidative and carbonyl stresses. Taken together, our results provide evidence that diHEP-DPA can inhibit cell damage caused by A2E and BL exposure at the cellular level by controlling various pathways involved in apoptosis and inflammatory responses.

Dynamic changes in proresolving lipid mediators and their receptors following acute vascular injury in male rats

Acute vascular injury provokes an inflammatory response, resulting in neointimal hyperplasia (NIH) and downstream pathologies. The resolution of inflammation is an active process in which specialized proresolving lipid mediators (SPM) and their receptors play a central role. We sought to examine the acute phase response of SPM and their receptors in both circulating blood and the arterial wall in a rat angioplasty model. We found that the ratio of proresolving to pro-inflammatory lipid mediators (LM) in plasma decreased sharply 1 day after vascular injury, then increased slightly by day 7, while that in arteries remained depressed. Granulocyte expression of SPM receptors ALX/FPR2 and DRV2/GPR18, and a leukotriene B4 receptor BLT1 increased postinjury, while ERV1/ChemR23 expression was reduced early and then recovered by day 7. Importantly, we show unique arterial expression patterns of SPM receptors in the acute setting, with generally low levels through day 7 that contrasted sharply with that of the pro-inflammatory CCR2 receptor. Overall, these data document acute, time-dependent changes of LM biosynthesis and SPM receptor expression in plasma, leukocytes, and artery walls following acute vascular injury. A biochemical imbalance between inflammation and resolution LM pathways appears persistent 7 days after angioplasty in this model. These findings may help guide therapeutic approaches to accelerate vascular healing and improve the outcomes of vascular interventions for patients with advanced atherosclerosis.

Role and mechanism of specialized pro-resolving mediators in obesity-associated insulin resistance

With the changing times, obesity has become a characteristic epidemic in the context of the current era. Insulin resistance (IR) is most commonly caused by obesity, and IR is a common basis of the pathogenesis of many diseases such as cardiovascular disease, nonalcoholic fatty liver disease, and type 2 diabetes, which seriously threaten human life, as well as health. A major pathogenetic mechanism of obesity-associated IR has been found to be chronic low-grade inflammation in adipose tissue. Specialized pro-resolving mediators (SPMs) are novel lipid mediators that both function as "stop signals" for inflammatory reaction and promote inflammation to subside. In this article, we summarize the pathogenesis of obesity-associated IR and its treatments and outline the classification and biosynthesis of SPMs and their mechanisms and roles in the treatment of obesity-associated IR in order to explore the potential of SPMs for treating metabolic diseases linked with obesity-associated IR.

A review of perioperative immune-modulating and metabolic-modulating nutrition strategies for bowel resection surgery

Focused perioperative nutrition strategies have proven benefits on the outcomes for patients undergoing major abdominal surgery. In this brief article, we will review these strategies and the evidence to support them with a focus on gastrointestinal anastomotic healing. We will elaborate the risks and benefits of enteral feeds, immune- and metabolic-modulating formulas, prebiotics and probiotics, and prehabilitation in preparation for surgery. Additionally, we will discuss the role of fish oils (eicosapentaenoic acid and docosahexaenoic acid) in the surgical patient and new data on specialized proresolving mediators in inflammation resolution. Finally, this article will consider the harmful impact surgical trauma has on the microbiome and the potential for perioperative dietary modulation to attenuate these negative effects.

Lipid mediators in neutrophil biology: inflammation, resolution and beyond

PURPOSE OF REVIEW

Acute inflammation is the body's first defense in response to pathogens or injury. Failure to efficiently resolve the inflammatory insult can severely affect tissue homeostasis, leading to chronic inflammation. Neutrophils play a pivotal role in eradicating infectious pathogens, orchestrating the initiation and resolution of acute inflammation, and maintaining physiological functions. The resolution of inflammation is a highly orchestrated biochemical process, partially modulated by a novel class of endogenous lipid mediators known as specialized pro-resolving mediators (SPMs). SPMs mediate their potent bioactions via activating specific cell-surface G protein-coupled receptors (GPCR).

RECENT FINDINGS

This review focuses on recent advances in understanding the multifaceted functions of SPMs, detailing their roles in expediting neutrophil apoptosis, promoting clearance by macrophages, regulating their excessive infiltration at inflammation sites, orchestrating bone marrow deployment, also enhances neutrophil phagocytosis and tissue repair mechanisms under both physiological and pathological conditions. We also focus on the novel role of SPMs in regulating bone marrow neutrophil functions, differentiation, and highlight open questions about SPMs' functions in neutrophil heterogeneity.

SUMMARY

SPMs play a pivotal role in mitigating excessive neutrophil infiltration and hyperactivity within pathological milieus, notably in conditions such as sepsis, cardiovascular disease, ischemic events, and cancer. This significant function highlights SPMs as promising therapeutic agents in the management of both acute and chronic inflammatory disorders.

Is Lipid Metabolism of Value in Cancer Research and Treatment? Part II: Role of Specialized Pro-Resolving Mediators in Inflammation, Infections, and Cancer

Acute inflammation is the body's first defense in response to pathogens or injury that is partially governed by a novel genus of endogenous lipid mediators that orchestrate the resolution of inflammation, coined specialized pro-resolving mediators (SPMs). SPMs, derived from omega-3-polyunstaturated fatty acids (PUFAs), include the eicosapentaenoic acid-derived and docosahexaenoic acid-derived Resolvins, Protectins, and Maresins. Herein, we review their biosynthesis, structural characteristics, and therapeutic effectiveness in various diseases such as ischemia, viral infections, periodontitis, neuroinflammatory diseases, cystic fibrosis, lung inflammation, herpes virus, and cancer, especially focusing on therapeutic effectiveness in respiratory inflammation and ischemia-related injuries. Resolvins are sub-nanomolar potent agonists that accelerate the resolution of inflammation by reducing excessive neutrophil infiltration, stimulating macrophage functions including phagocytosis, efferocytosis, and tissue repair. In addition to regulating neutrophils and macrophages, Resolvins control dendritic cell migration and T cell responses, and they also reduce the pro-inflammatory cytokines, proliferation, and metastasis of cancer cells. Importantly, several lines of evidence have demonstrated that Resolvins reduce tumor progression in melanoma, oral squamous cell carcinoma, lung cancer, and liver cancer. In addition, Resolvins enhance tumor cell debris clearance by macrophages in the tumor's microenvironment. Resolvins, with their unique stereochemical structure, receptors, and biosynthetic pathways, provide a novel therapeutical approach to activating resolution mechanisms during cancer progression.

Biotransformation of docosahexaenoic acid into 10R,17S-dihydroxydocosahexaenoic acid as protectin DX 10-epimer by serial reactions of arachidonate 8R- and 15S-lipoxygenases

Protectins, 10,17-dihydroxydocosahexaenoic acids (10,17-DiHDHAs), are belonged to specialized pro-resolving mediators (SPMs). Protectins are generated by polymorphonuclear leukocytes in humans and resolve inflammation and infection in trace amounts. However, the quantitative production of protectin DX 10-epimer (10-epi-PDX, 10R,17S-4Z,7Z,11E,13Z,15E,19Z-DiHDHA) has been not attempted to date. In this study, 10-epi-PDX was quantitatively produced from docosahexaenoic acid (DHA) by serial whole-cell biotransformation of Escherichia coli expressing arachidonate (ARA) 8R-lipoxygenase (8R-LOX) from the coral Plexaura homomalla and E. coli expressing ARA 15S-LOX from the bacterium Archangium violaceum. The optimal bioconversion conditions to produce 10R-hydroxydocosahexaenoic acid (10R-HDHA) and 10-epi-PDX were pH 8.0, 30 °C, 2.0 mM DHA, and 4.0 g/L cells; and pH 8.5, 20 °C, 1.4 mM 10R-HDHA, and 1.0 g/L cells, respectively. Under these optimized conditions, 2.0 mM (657 mg/L) DHA was converted into 1.2 mM (433 mg/L) 10-epi-PDX via 1.4 mM (482 mg/L) 10R-HDHA by the serial whole-cell biotransformation within 90 min, with a molar conversion of 60% and volumetric productivity of 0.8 mM/h (288 mg/L/h). To the best of our knowledge, this is the first quantitative production of 10-epi-PDX. Our results contribute to the efficient biocatalytic synthesis of SPMs.

Harnessing Oxylipins and Inflammation Modulation for Prevention and Treatment of Colorectal Cancer

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide, ranking as the third most malignant. The incidence of CRC has been increasing with time, and it is reported that Westernized diet and lifestyle play a significant role in its higher incidence and rapid progression. The intake of high amounts of omega-6 (n - 6) PUFAs and low levels of omega-3 (n - 3) PUFAs has an important role in chronic inflammation and cancer progression, which could be associated with the increase in CRC prevalence. Oxylipins generated from PUFAs are bioactive lipid mediators and have various functions, especially in inflammation and proliferation. Carcinogenesis is often a consequence of chronic inflammation, and evidence has shown the particular involvement of n - 6 PUFA arachidonic acid-derived oxylipins in CRC, which is further described in this review. A deeper understanding of the role and metabolism of PUFAs by their modifying enzymes, their pathways, and the corresponding oxylipins may allow us to identify new approaches to employ oxylipin-associated immunomodulation to enhance immunotherapy in cancer. This paper summarizes oxylipins identified in the context of the initiation, development, and metastasis of CRC. We further explore CRC chemo-prevention strategies that involve oxylipins as potential therapeutics.

The 125th Anniversary of Aspirin-The Story Continues

The year 2024 marks the 125th anniversary of aspirin, still one of the most frequently used drugs worldwide. Despite its veritable age, it is still relevant in pharmacotherapy and its use has spread to new areas over time. Due to aspirin's multiple pharmacological actions unified in one single molecule (i.e., analgesic, antipyretic, anti-inflammatory, antithrombotic, and antiviral effects), it continues to attract considerable attention in the scientific community and is subject to intense basic and clinical research. In fact, recent results confirmed aspirin's potential role as an antiviral drug and as an agent that can block harmful platelet functions in inflammatory/immunological processes. These features may open up new horizons for this ancient drug. The future of aspirin looks, therefore, bright and promising. Aspirin is not yet ready for retirement; on the contrary, its success story continues. This 125th anniversary paper will concisely review the various therapeutic uses of aspirin with a particular emphasis on the latest research results and their implications (e.g., use as an antiviral agent). In addition, the reader is provided with future perspectives for this remarkable drug.

Vagus nerve stimulation: Potential for treating chronic wounds

Vagus nerve stimulation (VNS) has been approved as a treatment for various conditions, including drug-resistant epilepsy, migraines, chronic cluster headaches and treatment-resistant depression. It is known to have anti-inflammatory, anti-nociceptive and anti-adrenergic effects, and its therapeutic potential for diverse pathologies is being investigated. VNS can be achieved through invasive (iVNS) or non-invasive (niVNS) means, targeting different branches of the vagus nerve. iVNS devices require surgical implantation and have associated risks, while niVNS devices are generally better tolerated and have a better safety profile. Studies have shown that both iVNS and niVNS can reduce inflammation and pain perception in patients with acute and chronic conditions. VNS devices, such as the VNS Therapy System and MicroTransponder Vivistim, have received Food and Drug Administration approval for specific indications. Other niVNS devices, like NEMOS and gammaCore, have shown effectiveness in managing epilepsy, pain and migraines. VNS has also demonstrated potential in autoimmune disorders, such as rheumatoid arthritis and Crohn's disease, as well as neurological disorders like epilepsy and migraines. In addition, VNS has been explored in cardiovascular disorders, including post-operative atrial fibrillation and myocardial ischemia-reperfusion injury, and has shown positive outcomes. The mechanisms behind VNS's effects include the cholinergic anti-inflammatory pathway, modulation of cytokines and activation of specialised pro-resolving mediators. The modulation of inflammation by VNS presents a promising avenue for investigating its potential to improve the healing of chronic wounds. However, more research is needed to understand the specific mechanisms and optimise the use of VNS in wound healing. Ongoing clinical trials may support the use of this modality as an adjunct to improve healing.

Interface between Resolvins and Efferocytosis in Health and Disease

Acute inflammation resolution acts as a vital process for active host response, tissue support, and homeostasis maintenance, during which resolvin D (RvD) and E (RvE) as mediators derived from omega-3 polyunsaturated fatty acids display specific and stereoselective anti-inflammations like restricting neutrophil infiltration and pro-resolving activities. On the other side of the coin, potent macrophage-mediated apoptotic cell clearance, namely efferocytosis, is essential for successful inflammation resolution. Further studies mentioned a linkage between efferocytosis and resolvins. For instance, resolvin D1 (RvD1), which is endogenously formed from docosahexaenoic acid within the inflammation resolution, thereby provoking efferocytosis. There is still limited information regarding the mechanism of action of RvD1-related efferocytosis enhancement at the molecular level. The current review article was conducted to explore recent data on how the efferocytosis process and resolvins relate to each other during the inflammation resolution in illness and health. Understanding different aspects of this connection sheds light on new curative approaches for medical conditions caused by defective efferocytosis and disrupted inflammation resolution.

Supplementation with Silybum marianum Extract, Synbiotics, Omega-3 Fatty Acids, Vitamins, and Minerals: Impact on Biochemical Markers and Fecal Microbiome in Overweight Dogs

Overweight and obese dogs can develop metabolic dysfunction, characterized by an inflammatory response and involvement of liver functions. If a modulation of the gut microbiome and its interaction with the gut-liver axis is implicated in the development of metabolic dysfunction, exploration becomes necessary. Over the past decade, diverse therapeutic approaches have emerged to target pathogenic factors involved in metabolic dysfunction. This study investigated the impact of a supplement with hepatoprotective activity, containing extracts of Silybum marianum, prebiotics, probiotics, n-3 polyunsaturated fatty acids, vitamins, and minerals on hematological markers of liver functions and inflammation, as well as on the intestinal microbiota of 10 overweight adult dogs over a 35-day time span. Animals underwent clinical and laboratory evaluations every 7 days, both before the administration of the supplement (T0) and after 7, 14, 21, 28, and 35 days (T1, T2, T3, T4, and T5). In comparison to T0, a significant (p < 0.05) decrease in ALP, glucose, direct bilirubin, and CRP was observed from T3 to T5. The alpha diversity of the fecal microbiota significantly decreased (p < 0.05) only at T1, with high variability observed between dogs. Total short-chain fatty acid and lactic acid were also lower at T1 (p < 0.05) compared to the other times of sampling. The beta diversity of the fecal microbiota failed to show a clear pattern in relation to the sampling times. These results of blood parameters in overweight dogs show a reduction of the inflammation and an improvement of metabolic status during the study period, but the effective contribution of the supplement in this clinical outcome deserves further investigation. Furthermore, the considerable individual variability observed in the microbiome hinders the confident detection of supplement effects.

The role of specialized pro-resolving mediators (SPMs) in inflammatory arthritis: A therapeutic strategy

Rheumatoid arthritis (RA) is classified as a persistent inflammatory autoimmune disorder leading to the subsequent erosion of articular cartilage and bone tissue originating from the synovium. The fundamental objective of therapeutic interventions in RA has been the suppression of inflammation. Nevertheless, conventional medicines that lack target specificity may exhibit unpredictable effects on cell metabolism. In recent times, there has been evidence suggesting that specialized pro-resolving mediators (SPMs), which are lipid metabolites, have a role in facilitating the resolution of inflammation and the reestablishment of tissue homeostasis. SPMs are synthesized by immune cells through the enzymatic conversion of omega-3 fatty acids. In the context of RA, there is a possibility of dysregulation in the production of these SPMs. In this review, we delve into the present comprehension of the endogenous functions of SPMs in RA as lipids that exhibit pro-resolutive, protective, and immunoresolvent properties.

Combining proteins with n-3 PUFAs (EPA + DHA) and their inflammation pro-resolution mediators for preservation of skeletal muscle mass

The optimal feeding strategy for critically ill patients is still debated, but feeding must be adapted to individual patient needs. Critically ill patients are at risk of muscle catabolism, leading to loss of muscle mass and its consequent clinical impacts. Timing of introduction of feeding and protein targets have been explored in recent trials. These suggest that "moderate" protein provision (maximum 1.2 g/kg/day) is best during the initial stages of illness. Unresolved inflammation may be a key factor in driving muscle catabolism. The omega-3 (n-3) fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are substrates for synthesis of mediators termed specialized pro-resolving mediators or SPMs that actively resolve inflammation. There is evidence from other settings that high-dose oral EPA + DHA increases muscle protein synthesis, decreases muscle protein breakdown, and maintains muscle mass. SPMs may be responsible for some of these effects, especially upon muscle protein breakdown. Given these findings, provision of EPA and DHA as part of medical nutritional therapy in critically ill patients at risk of loss of muscle mass seems to be a strategy to prevent the persistence of inflammation and the related anabolic resistance and muscle loss.

Molecular Mechanisms Associated with the Inhibitory Role of Long Chain n-3 PUFA in Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related death in the world. Multiple evidence suggests that there is an association between excess fat consumption and the risk of CRC. The long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential for human health, and both in vitro and in vivo studies have shown that these fatty acids can prevent CRC development through various molecular mechanisms. These include the modulation of arachidonic acid (AA) derived prostaglandin synthesis, alteration of growth signaling pathways, arrest of the cell cycle, induction of cell apoptosis, suppression of angiogenesis and modulation of inflammatory response. Human clinical studies found that LC n-3 PUFA combined with chemotherapeutic agents can improve the efficacy of treatment and reduce the dosage of chemotherapy and associated side effects. In this review, we discuss comprehensively the anti-cancer effects of LC n-3 PUFA on CRC, with a main focus on the underlying molecular mechanisms.

Leishmania mexicana promotes pain-reducing metabolomic reprogramming in cutaneous lesions

Cutaneous leishmaniasis (CL) is characterized by extensive skin lesions, which are usually painless despite being associated with extensive inflammation. The molecular mechanisms responsible for this analgesia have not been identified. Through untargeted metabolomics, we found enriched anti-nociceptive metabolic pathways in L. mexicana-infected mice. Purines were elevated in infected macrophages and at the lesion site during chronic infection. These purines have anti-inflammatory and analgesic properties by acting through adenosine receptors, inhibiting TRPV1 channels, and promoting IL-10 production. We also found arachidonic acid (AA) metabolism enriched in the ear lesions compared to the non-infected controls. AA is a metabolite of anandamide (AEA) and 2-arachidonoylglycerol (2-AG). These endocannabinoids act on cannabinoid receptors 1 and 2 and TRPV1 channels to exert anti-inflammatory and analgesic effects. Our study provides evidence of metabolic pathways upregulated during L. mexicana infection that may mediate anti-nociceptive effects experienced by CL patients and identifies macrophages as a source of these metabolites.

Modifications of Blood Molecular Components after Treatment with Low Ozone Concentrations

The ex vivo treatment of a limited volume of blood with gaseous oxygen-ozone (O2-O3) mixtures and its rapid reinfusion into the patient is a widespread medical procedure. O3 instantly reacts with the blood's antioxidant systems, disappearing before reinfusion, although the molecules formed act as messengers in the organism, inducing multiple antioxidant and anti-inflammatory responses. An appropriate dose of O3 is obviously essential to ensure both safety and therapeutic efficacy, and in recent years, the low-dose O3 concept has led to a significant reduction in the administered O3 concentrations. However, the molecular events triggered by such low concentrations in the blood still need to be fully elucidated. In this basic study, we analysed the molecular modifications induced ex vivo in sheep blood by 5 and 10 µg O3/mL O2 by means of a powerful metabolomics analysis in association with haemogas, light microscopy and bioanalytical assays. This combined approach revealed increased oxygenation and an increased antioxidant capacity in the O3-treated blood, which accorded with the literature. Moreover, original information was obtained on the impact of these low O3 concentrations on the metabolic pathways of amino acids, carbohydrates, lipids and nucleotides, with the modified metabolites being mostly involved in the preservation of the oxidant-antioxidant balance and in energy production.

The biosynthetic pathways of the protectins

Evidence for the biosynthetic pathways of the specialized pro-resolving mediator (SPM) protectin D1 (PD1) and its biochemical further local metabolism were presented during the 8th European Workshop on Lipid Mediators, organized June 29th-July 1st, 2022, in Stockholm, Sweden. Herein, we provide an extended and detailed discussion of these topics. PD1, one of 43 SPMs reported so far, exhibits very potent pro-resolution and anti-inflammatory bioactions. Many research groups worldwide have confirmed these and other interesting bioactions. The protectins constitute, together with the lipoxins, resolvins, and maresins, the four individual SPM families, which have received a great interest in basic biomedical research and drug discovery efforts.

Pro-resolving and anti-inflammatory effects of resolvins and protectins in rheumatoid arthritis

Rheumatoid arthritis (RA) is typified by persistent joint inflammation, which leads to the deterioration of bone and cartilage and a reduction in overall quality of life. The global prevalence of pain as a primary symptom in RA is influenced by the interplay between inflammation and its resolution. The identification of a family of lipid mediators known as specialized pro-resolving mediators (SPM)s has contributed to the progress of our comprehension of inflammatory conditions. SPMs have been observed to trigger the process of inflammation resolution, thereby reinstating the homeostasis of the inflammatory response. Autacoids are synthesized through the stereo-selective transformation of essential fatty acids, resulting in molecules dynamically modulated during inflammation and possessing strong immunoregulatory properties. This review delves into the available evidence that supports the involvement of certain SPM as protective lipids, biomarkers with potential, and therapeutic targets in the context of RA.

Maternal DHA intake in mice increased DHA metabolites in the pup brain and ameliorated MeHg-induced behavioral disorder

Although pregnant women's fish consumption is beneficial for the brain development of the fetus due to the DHA in fish, seafood also contains methylmercury (MeHg), which adversely affects fetal brain development. Epidemiological studies suggest that high DHA levels in pregnant women's sera may protect the fetal brain from MeHg-induced neurotoxicity, but the underlying mechanism is unknown. Our earlier study revealed that DHA and its metabolite 19,20-dihydroxydocosapentaenoic acid (19,20-DHDP) produced by cytochrome P450s (P450s) and soluble epoxide hydrolase (sEH) can suppress MeHg-induced cytotoxicity in mouse primary neuronal cells. In the present study, DHA supplementation to pregnant mice suppressed MeHg-induced impairments of pups' body weight, grip strength, motor function, and short-term memory. DHA supplementation also suppressed MeHg-induced oxidative stress and the decrease in the number of subplate neurons in the cerebral cortex of the pups. DHA supplementation to dams significantly increased the DHA metabolites 19,20-epoxydocosapentaenoic acid (19,20-EDP) and 19,20-DHDP as well as DHA itself in the fetal and infant brains, although the expression levels of P450s and sEH were low in the fetal brain and liver. DHA metabolites were detected in the mouse breast milk and in human umbilical cord blood, indicating the active transfer of DHA metabolites from dams to pups. These results demonstrate that DHA supplementation increased DHA and its metabolites in the mouse pup brain and alleviated the effects of MeHg on fetal brain development. Pregnant women's intake of fish containing high levels of DHA (or DHA supplementation) may help prevent MeHg-induced neurotoxicity in the fetus.

Network pharmacology based virtual screening of Flavonoids from Dodonea angustifolia and the molecular mechanism against inflammation

Inflammation is a nonspecific immune response against injury caused by a harmful agent that strives to restore tissue function and homeostasis. Dodonaea angustifolia L.f. (Sapindaceae) is a medium-sized shrub used to treat a variety of diseases in traditional medicine. In the current study, integrated network-pharmacology and molecular docking approaches were used to identify the active constituents, their possible targets, signaling pathways, and anti-inflammatory effects of flavonoids from D.angustifolia. D. angustifolia active ingredients were acquired from the Indian Medicinal Plants, Phytochemistry and Therapeutics (IMPPAT), and Traditional Chinese Medicine System Pharmacology (TCMSP) databases. The screening included the ten most prevalent D. angustifolia components, and the SwissTargetPrediction database was utilized to anticipate the targets of these compounds. Anti-inflammatory genes were found using the GeneCards database. The 175 overlapping genes were discovered as prospective D. angustifolia anti-inflammatory targets. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the overlapped targets were closely related to the major pathogenic processes linked to inflammation, such as response to organonitrogen compound, protein kinase activity, phosphotransferase activity, pI3k-Akt signaling pathway, metabolic pathways, and chemical carcinogenesis. Compound-target-pathway, and protein-protein interaction networks revealed 6-Methoxykaempferol and 5-Hydroxy-7,8 dimethoxyflavone as key compounds, and AKT1, VEGFA, and EGFR as key targets. Furthermore, molecular docking followed by molecular dynamic (MD) simulation of D. angustifolia active ingredients with core proteins fully complemented the binding affinity of these compounds and indicated stable complexes at the docked site. These findings reveal D. angustifolia 's multi-target, multi-compound, and multi-pathway strategies against inflammation. Our study paved the way for further research into the mechanism for developing D. angustifolia -based natural products as alternative therapies for inflammation.

Review of Eukaryote Cellular Membrane Lipid Composition, with Special Attention to the Fatty Acids

Biological membranes, primarily composed of lipids, envelop each living cell. The intricate composition and organization of membrane lipids, including the variety of fatty acids they encompass, serve a dynamic role in sustaining cellular structural integrity and functionality. Typically, modifications in lipid composition coincide with consequential alterations in universally significant signaling pathways. Exploring the various fatty acids, which serve as the foundational building blocks of membrane lipids, provides crucial insights into the underlying mechanisms governing a myriad of cellular processes, such as membrane fluidity, protein trafficking, signal transduction, intercellular communication, and the etiology of certain metabolic disorders. Furthermore, comprehending how alterations in the lipid composition, especially concerning the fatty acid profile, either contribute to or prevent the onset of pathological conditions stands as a compelling area of research. Hence, this review aims to meticulously introduce the intricacies of membrane lipids and their constituent fatty acids in a healthy organism, thereby illuminating their remarkable diversity and profound influence on cellular function. Furthermore, this review aspires to highlight some potential therapeutic targets for various pathological conditions that may be ameliorated through dietary fatty acid supplements. The initial section of this review expounds on the eukaryotic biomembranes and their complex lipids. Subsequent sections provide insights into the synthesis, membrane incorporation, and distribution of fatty acids across various fractions of membrane lipids. The last section highlights the functional significance of membrane-associated fatty acids and their innate capacity to shape the various cellular physiological responses.

Omega-3 Lipid Mediators: Modulation of the M1/M2 Macrophage Phenotype and Its Protective Role in Chronic Liver Diseases

The complex interplay between dietary factors, inflammation, and macrophage polarization is pivotal in the pathogenesis and progression of chronic liver diseases (CLDs). Omega-3 fatty acids (FAs) have brought in attention due to their potential to modulate inflammation and exert protective effects in various pathological conditions. Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have shown promise in mitigating inflammation and enhancing the resolution of inflammatory responses. They influence the M1/M2 macrophage phenotype balance, promoting a shift towards the M2 anti-inflammatory phenotype. Specialized pro-resolving mediators (SPMs), such as resolvins (Rvs), protectins (PDs), and maresins (MaRs), have emerged as potent regulators of inflammation and macrophage polarization. They show anti-inflammatory and pro-resolving properties, by modulating the expression of cytokines, facilitate the phagocytosis of apoptotic cells, and promote tissue repair. MaR1, in particular, has demonstrated significant hepatoprotective effects by promoting M2 macrophage polarization, reducing oxidative stress, and inhibiting key inflammatory pathways such as NF-κB. In the context of CLDs, such as nonalcoholic fatty liver disease (NAFLD) and cirrhosis, omega-3s and their SPMs have shown promise in attenuating liver injury, promoting tissue regeneration, and modulating macrophage phenotypes. The aim of this article was to analyze the emerging role of omega-3 FAs and their SPMs in the context of macrophage polarization, with special interest in the mechanisms underlying their effects and their interactions with other cell types within the liver microenvironment, focused on CLDs and the development of novel therapeutic strategies.

Periodontal and cardiovascular therapies modify specialized pro-resolving lipid mediator (sPRLM) (LPXA4, PD1, RvE1, RvD1, and MaR1)-mediated pathway: the first pilot clinical study

OBJECTIVES

Cardiovascular disease (CVD) and periodontal disease have a common pathogenesis with inflammation and resolution steps. Although the relationships among periodontal disease, CVD, and specialized pro-resolving lipid mediator (sPRLM)s are well known, there is no study about the combined effects of cardiovascular and periodontal treatments on sPRLM levels. It was aimed to evaluate the effects of periodontal and cardiovascular therapies on sPRLMs (lipoxin A4, protectin (PD)1, resolvin (Rv) E1, RvD1, and maresin (MaR)1) in patients with CVD and periodontal disease.

METHODS

This observational study consisted of fifty-five patients with CVD and mild or moderate periodontitis. The clinical periodontal parameters (plaque index, gingival index, probing pocket depth, percentage of bleeding on probing, and clinical attachment level) and blood and unstimulated total saliva samples were obtained at baseline, at 3 months (following only cardiovascular therapy), and at 6 months (following cardiovascular and periodontal therapies). The blood count and serum levels of cardiometabolic biomarkers (white blood cell, neutrophil/lymphocyte, serum total cholesterol (TC), triglyceride, and low and high-density lipoprotein (HDL) levels) were evaluated. sPRLMs were evaluated by ELISA.

RESULTS

There were significant decreases in body mass index, clinical periodontal parameters, WBC, LDL, PD1, and RvD1 at 6 months compared to baseline. The decreases in TC/HDL, RvE1, and MaR1 levels were significant at 3 and 6 months compared to baseline (p < 0.05).

CONCLUSION(S)

The combination of cardiovascular and periodontal treatments leads to significant reductions in clinical periodontal and cardiometabolic parameters and sPRLMs.

CLINICAL RELEVANCE

Our report, which is the first in their field, suggested that cardiovascular and periodontal therapies provide an important contribution via decreasing the periodontal and atherosclerotic inflammation modulating sPRLMs. This finding will be a big step toward increasing the quality of life in these patients by drawing attention to importance of public health associated with oral hygiene, periodontal health, and systemic phase of periodontal treatment.

Fatty acids, inflammation and angiogenesis in women with gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a metabolic disorder in pregnancy whose prevalence is on the rise. Reports suggest a likely association between inflammation and maternal GDM. A balance between pro and anti-inflammatory cytokines is necessary for the regulation of maternal inflammation system throughout pregnancy. Along with various inflammatory markers, fatty acids also act as pro-inflammatory molecules. However, studies reporting the role of inflammatory markers in GDM are contradictory, suggesting the need of more studies to better understand the role of inflammation in pregnancies complicated by GDM. Inflammatory response can be regulated by angiopoietins suggesting a link between inflammation and angiogenesis. Placental angiogenesis is a normal physiological process which is tightly regulated during pregnancy. Various pro and anti-angiogenic factors influence the regulation of the feto-placental vascular development. Studies evaluating the levels of angiogenic markers in women with GDM are limited and the findings are inconsistent. This review summarizes the available literature on fatty acids, inflammatory markers and angiogenesis in women with GDM. We also discuss the possible link between them and their influence on placental development in GDM.

Transgenic mice overexpressing human ALOX15 under the control of the aP2 promoter are partly protected in the complete Freund's adjuvant-induced paw inflammation model

BACKGROUND, OBJECTIVES AND DESIGN

Arachidonic acid 15-lipoxygenase (ALOX15) has been implicated in the pathogenesis of inflammatory diseases but since pro- and anti-inflammatory roles have been suggested, the precise function of this enzyme is still a matter of discussion. To contribute to this discussion, we created transgenic mice, which express human ALOX15 under the control of the activating protein 2 promoter (aP2-ALOX15 mice) and compared the sensitivity of these gain-of-function animals in two independent mouse inflammation models with Alox15-deficient mice (loss-of-function animals) and wildtype control animals.

MATERIALS AND METHODS

Transgenic aP2-ALOX15 mice were tested in comparison with Alox15 knockout mice (Alox15-/-) and corresponding wildtype control animals (C57BL/6J) in the complete Freund's adjuvant induced hind-paw edema model and in the dextran sulfate sodium induced colitis (DSS-colitis) model. In the paw edema model, the degree of paw swelling and the sensitivity of the inflamed hind-paw for mechanic (von Frey test) and thermal (Hargreaves test) stimulation were quantified as clinical readout parameters. In the dextran sodium sulfate induced colitis model the loss of body weight, the colon lengths and the disease activity index were determined.

RESULTS

In the hind-paw edema model, systemic inactivation of the endogenous Alox15 gene intensified the inflammatory symptoms, whereas overexpression of human ALOX15 reduced the degree of hind-paw inflammation. These data suggest anti-inflammatory roles for endogenous and transgenic ALOX15 in this particular inflammation model. As mechanistic reason for the protective effect downregulation of the pro-inflammatory ALOX5 pathways was suggested. However, in the dextran sodium sulfate colitis model, in which systemic inactivation of the Alox15 gene protected female mice from DSS-induced colitis, transgenic overexpression of human ALOX15 did hardly impact the intensity of the inflammatory symptoms.

CONCLUSION

The biological role of ALOX15 in the pathogenesis of inflammation is variable and depends on the kind of the animal inflammation model.

Protectin DX as a therapeutic strategy against frailty in mice

Frailty in aging is driven by the dysregulation of multiple biological pathways. Protectin DX (PDX) is a docosahexaenoic acid (DHA)-derived molecule that alleviates many chronic inflammatory disorders, but its potential effects on frailty remain unknown. Our goal is to identify age-related impairments in metabolic systems and to evaluate the therapeutic potential of PDX on frailty, physical performance, and health parameters. A set of 22-month-old C57BL/6 male and female mice were assigned to vehicle (Old) or PDX daily gavage treatment for 9 weeks, whereas 6-month-old (Adult) mice received only vehicle. Forelimb and hindlimb strength, endurance, voluntary wheel activity and walking speed determined physical performance and were combined with a frailty index score and body weight loss to determine frailty status. Our data shows that old vehicle-treated mice from both sexes had body weight loss paralleling visceromegaly, and Old females also had impaired insulin clearance as compared to the Adult group. Aging was associated with physical performance decline together with higher odds of frailty development. There was also age-driven mesangial expansion and glomerular hypertrophy as well as bone mineral density loss. All of the in vivo and in vitro impairments observed with aging co-occurred with upregulation of inflammatory pathways and Myc signaling as well as downregulation of genes related to adipogenesis and oxidative phosphorylation in liver. PDX attenuated the age-driven physical performance (strength, exhaustion, walking speed) decline, promoted robustness, prevented bone losses and partially reversed changes in hepatic expression of Myc targets and metabolic genes. In conclusion, our data provides evidence of the beneficial therapeutic effect of PDX against features of frailty in mice. Further studies are warranted to investigate the mechanisms of action and the potential for human translation.