Resolvins: a family of bioactive products of omega-3 fatty acid transformation circuits initiated by aspirin treatment that counter proinflammation signals

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.

Immunoregulatory macrophages induced by mycobacterial nonpolar lipids

The capacity of Mycobacterium tuberculosis (Mtb) to establish long-term survival is attributed to its ability to subvert host defense mechanisms, especially macrophages. Although Mtb lipids are believed to play a role in this host-pathogen crosstalk, how mycobacterial lipids drive this complex interaction is poorly characterized. Here, we cultured macrophages with nonpolar cell wall Mtb lipids and applied high-throughput expression profiling (RNA sequencing), mass spectrometry-based targeted eicosanoid, and untargeted lipidomics analysis. This system-level analysis revealed that Mtb nonpolar lipid triggered the expression of phenotypic markers for classically and alternatively activated macrophages, a state previously referred as immunoregulatory. Specifically, under lipid stimulation, macrophages expressed high levels of proinflammatory markers, activated components of the interleukin-1 family, underwent an imbalance in lipid metabolism, and shifted the eicosanoid synthesis pathway toward the prostaglandin axis. Taken together, these results suggest an intricate mechanism of Mtb-driven macrophage immunomodulation that may favor its long-term survival.

On the Total Synthesis of 7,8(S,S)-Epoxy-17(S)-hydroxy-4(Z),9(E),11(E),13(Z),15(E),19(Z)-docosahexaenoic Acid Derivative

The stereoselective total synthesis of an allylic epoxide-containing polyunsaturated fatty acid, in its triethylsilyl (TES) ether and methyl ester form, is described. Key features include a Sharpless enantioselective epoxidation to install the oxirane unit and Wittig coupling reactions to forge critical alkenyl configuration and secure the core carbon skeleton. The deprotected epoxy acid was recently demonstrated to play a central role as the precursor to biologically active resolvins D1, D2, and the cysteinyl conjugate in tissue regeneration (RCTR1) by human leukocytes. These natural products belong to a family of cell signaling molecules termed specialized pro-resolving mediators (SPMs).

Immune Dysregulation in Depression and Anxiety: A Review of the Immune Response in Disease and Treatment

Rates of depression and anxiety have increased significantly in recent decades, with many patients experiencing treatment-resistant symptoms. Beyond psychiatric manifestations, these conditions are associated with heightened risks of suicide, cardiovascular disease, chronic pain, and fatigue. Emerging research suggests that neuroinflammation, immune dysregulation, and hypothalamic-pituitary-adrenal axis dysfunction contribute to their pathophysiology, often interacting bidirectionally with stress. While current first-line treatments primarily target neurotransmitter imbalances, many patients do not achieve symptom resolution, highlighting the need for novel approaches. This review explores the role of immune dysfunction, cytokine activity, and neurotransmitter interactions in depression and anxiety. Additionally, we examine how existing pharmacological and non-pharmacological interventions influence inflammation and immune responses. Understanding these mechanisms may pave the way for more integrative treatment strategies that combine immune modulation with traditional psychiatric therapies.

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.

Targeting Inflammatory Imbalance in Chronic Kidney Disease: Focus on Anti-Inflammatory and Resolution Mediators

Chronic kidney disease (CKD) is a condition caused by the gradual decline of renal function that approximatively affects 10-12% of the world population, thus representing a public health priority. In CKD patients, chronic and systemic low-grade inflammation is observed, and it significantly contributes to disease development and progression, especially for patients with advanced disease. It also results in CKD-associated complications and increased mortality. The low-grade inflammation is due to different factors, such as the decline of glomerular filtration rate, increased immune system activation, reactive oxygen species release, and intestinal homeostasis. Therefore, the possibility to control chronic low-grade inflammation in CKD deserves great attention. In this review, we will examine the current possible pharmacological approaches to counteract the inflammatory state in CKD, focusing our attention both on the pro-inflammatory factors and the pro-resolving mediators involved in CKD inflammatory state.

Polyunsaturated Fatty Acid Imbalance-A Contributor to SARS CoV-2 Disease Severity

Overview: SARS CoV-2 infection is accompanied by the development of acute inflammation, resolution of which determines the course of infection and its outcome. If not resolved (brought back to preinjury status), the inflamed state progresses to a severe clinical presentation characterized by uncontrolled cytokine release, systemic inflammation, and in some death. In severe CoV-2 disease, the required balance between protective inflammation and its resolution appears missing, suggesting that the ω-3-derived specialized proresolving mediators (SPMs) needed for resolution are either not present or present at ineffective levels compared to competing ω-6 polyunsaturated fatty acid (PUFA) metabolic derivatives. Aim: To determine whether ω-6 PUFA linoleic acid (LA) metabolites increased in those infected with severe disease compared to uninfected controls. Findings: Increased levels of ω-6 LA metabolites, e.g., arachidonic acid (AA), epoxyeicosatrienoic (EET) acid derivatives of AA (8,9-, 11,12-, and 14,15-EETs), AA-derived hydroxyeicosatetraenoic (HETE) acid, dihydroxylated diols (leukotoxin and isoleukotoxin), and prostaglandin E2 with decreased levels of ω-3-derived inflammation resolving SPMs. Therapeutic treatment of SARS CoV-2 patients with ω-3 PUFA significantly increased 18-HEPE (SPM precursor) and EPA-derived diols (11,12- and 14,15-diHETE), while toxic 9,10- and 12,13-diHOMEs (leukotoxin and iosleukotoxin, respectively) decreased. Conclusion: Unbalanced dietary intake of ω-6/ω-3 PUFAs contributed to SARS CoV-2 disease severity by decreasing ω-3-dependent SPM resolution of inflammation and increasing membrane-associated ferroptotic AA peroxidation.

Delayed viral clearance and altered inflammatory responses affect severity of SARS-CoV-2 infection in aged mice

Epidemiological investigations consistently demonstrate an overrepresentation of the elderly in COVID-19 hospitalizations and fatalities, making the advanced age as a major predictor of disease severity. Despite this, a comprehensive understanding of the cellular and molecular mechanisms explaining how old age represents a major risk factor remain elusive. To investigate this, we compared SARS-CoV-2 infection outcomes in young adults (2 months) and geriatric (15-22 months) mice. Both groups of K18-ACE2 mice were intranasally infected with 500 TCID50 of SARS-CoV-2 Delta variant with analyses performed on days 3, 5, and 7 post-infection (DPI). Analyses included pulmonary cytokines, lung RNA-seq, viral loads, lipidomic profiles, and histological assessments, with a concurrent evaluation of the percentage of mice reaching humane endpoints. The findings unveiled notable differences, with aged mice exhibiting impaired viral clearance, reduced survival, and failure to recover weight loss due to infection. RNA-seq data suggested greater lung damage and reduced respiratory function in infected aged mice. Additionally, elderly-infected mice exhibited a deficient antiviral response characterized by reduced Th1-associated mediators (IFNγ, CCL2, CCL3, CXCL9) and diminished number of macrophages, NK cells, and T cells. Furthermore, mass-spectrometry analysis of the lung lipidome indicated altered expression of several lipids with immunomodulatory and pro-resolution effects in aged mice such as Resolvin, HOTrEs, and NeuroP, but also DiHOMEs-related ARDS. These findings indicate that aging affects antiviral immunity, leading to prolonged infection, greater lung damage, and poorer clinical outcomes. This underscores the potential efficacy of immunomodulatory treatments for elderly subjects experiencing symptoms of severe COVID-19.

Trends and hotspots in burns-related pain research: A bibliometric analysis

OBJECTIVE

The aim of this investigation was to conduct a thorough synthesis of the extant scholarly discourse and to delineate the prevailing global trends in the domain of burn pain, employing a bibliometric analysis.

METHODS

A bibliometric analysis was performed utilizing the Web of Science Core Collection database. Articles were selected based on titles or abstracts containing keywords associated with burns and pain. Both quantitative and qualitative methodologies were applied to examine the retrieved data, encompassing an analysis of publication trends, research themes, and collaboration networks.

RESULTS

The number of articles on this topic has been increasing, averaging an annual growth rate of 6.9 % from 1997 to 2023. Contributions have come from 645 institutions across 53 countries, resulting in 446 papers that span areas such as nursing, anesthesia, and immunology. Key journals include Burns, Journal of Burn Care & Research, and Pain. The United States has demonstrated a significant research output in this field, with active international collaboration, notably with Washington University leading in contributions. Patterson DR was the most prolific author in terms of published papers, while Choiniere M was the most frequently co-cited author. The focus of research has shifted from symptom management to exploring pain mechanisms. Current research priorities in burn pain include "quality of life," "music therapy," and "psychological state." Recent analysis has highlighted key areas in neuropathic pain mechanisms, novel analgesic therapies, and specific groups such as pediatric burn patients. Influential studies have advanced our understanding of pathophysiology, while psychological interventions and inflammation are increasingly receiving attention. Emerging topics include non-pharmacological interventions, psychological support, technology in pain assessment and management, quality of life, and personalized pain management.

CONCLUSION

Research on burn pain is advancing rapidly; however, collaboration among countries and institutions remains limited. Increased cooperation and communication across these entities could significantly advance the field in the future. Future research should prioritize placebo-controlled trials of targeted therapeutic drugs and innovative pain management approaches, with a strong emphasis on patient outcomes and quality of life.

Neuroimmunology of psoriasis: Possible roles for calcitonin gene-related peptide in its pathogenesis

The nervous system has a complex interplay with the immune system, especially at barrier sites such as the skin. This allows it to play a role in a variety of cutaneous inflammatory disorders such as psoriasis, exerting effects on various immune cells via effector molecules such as neuropeptides. In this review, we discuss the role of calcitonin gene-related peptide in modulating the immune system and inflammation, with a focus on psoriasis.

Aspirin-triggered DHA metabolites inhibit angiogenesis

Background and aim

Blood vessels supply oxygen, nutrients and provide gateways for immune surveillance. Since this network nourishes all tissues, vessel abnormalities contribute to many diseases, such as cancer. One of the potential targets for Docosahexaenoic Acid (DHA) in cancer is suppressing angiogenesis, a process of new blood vessel formation within tumors. In addition, aspirin (ASA) has antineoplastic effects that may be mediated, at least in part, by metabolites derived from acetylated COX-2. We aimed at determining the effect of DHA as well as its metabolites in angiogenesis, using in vitro as well as in vivo models.

Methods

Endothelial cell (EC) proliferation, motility and capillary-like tube formation were determined by MTT, wound healing, Boyden and Matrigel assays, respectively. In vivo angiogenesis was measured by the Matrigel sponge model in mice. The biosynthesis of proresolving lipid mediators by ECs was determined by LC-MS-MS.

Results and conclusion

DHA, but not arachidonic acid (AA), at concentrations consistent with those reached in blood after fish oil supplementation, decreased EC migration in a time- and concentration-dependent manner. Pretreatment with ASA modulated cell migration already after 24 h, while both DHA and ASA decreased migration at longer incubation times without affecting viability. 17-hydroxy-DHA was detected upon incubation with DHA, and increased amounts were observed upon combined treatment with DHA and ASA, an increase that was associated to a synergic effect on EC migration. 17(R)-hydroxy-DHA (17R-HDHA), the metabolite resulting from acetylated COX-2 activity of DHA, reduced EC migration in a concentration-dependent manner. DHA in the presence of ASA, as well as 17R-HDHA, also reduced EC tube formation. These results were confirmed in vivo where both 17R-HDHA or its downstream metabolite 17RResolvinD1 were able to decrease microvessels density in a Matrigel sponge model. Overall, we demonstrated that DHA in the presence of ASA-dependent acetylation of COX-2 showed increased antiangiogenic effects, possibly resulting from its conversion to its hydroxylated derivatives.

The Role of Endogenous Specialized Proresolving Mediators in Mast Cells and Their Involvement in Inflammation and Resolution

Many polyunsaturated fatty acids within cells exhibit diverse physiological functions. Particularly, arachidonic acid is the precursor of highly bioactive prostaglandins and leukotrienes, which are pro-inflammatory mediators. However, polyunsaturated fatty acids, such as arachidonic, docosahexaenoic, and eicosapentaenoic acids, can be metabolized into specialized proresolving mediators (SPMs), which have anti-inflammatory properties. Given that pro-inflammatory mediators and SPMs are produced via similar enzymatic pathways, SPMs can play a crucial role in mitigating excessive tissue damage induced by inflammation. Mast cells are immune cells that are widely distributed and strategically positioned at interfaces with the external environment, such as the skin and mucosa. As immune system sentinels, they respond to harmful pathogens and foreign substances. Upon activation, mast cells release various pro-inflammatory mediators, initiating an inflammatory response. Furthermore, these cells secrete factors that promote tissue repair and inhibit inflammation. This dual function positions mast cells as central regulators, balancing between the body's defense mechanisms and the need to minimize tissue injury. This review investigates the production of SPMs by mast cells and their subsequent effects on these cells. By elucidating the intricate relationship between mast cells and SPMs, this review aims to provide a comprehensive understanding of the mechanism by which these cells regulate the delicate balance between tissue damage and repair at inflammatory sites, ultimately contributing to the resolution of inflammatory responses.

Lipid Metabolism: An Emerging Player in Sjögren's Syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disorder that primarily affects the exocrine glands. Due to the intricate nature of the disease progression, the exact mechanisms underlying SS are not completely understood. Recent research has highlighted the complex interplay between immune dysregulation and metabolic abnormalities in inflammatory diseases. Notably, lipid metabolism has emerged as a crucial factor in the modulation of immune function and the progression of autoimmune diseases, including SS. This review explores the prevalence of dyslipidemia in SS, emphasizing its role in the onset, progression, and prognosis of the disease. We specifically described the impact of altered lipid metabolism in exocrine glands and its association with disease-specific features, including inflammation and glandular dysfunction. Additionally, we discussed the potential clinical implications of lipid metabolism regulation, including the role of polyunsaturated fatty acids (PUFAs) and their deficits in SS pathogenesis. By identifying lipid metabolism as a promising therapeutic target, this review highlights the need for further research into lipid-based interventions for the management of SS.

Immunomodulatory functions of algal bioactive compounds

Algae, a crucial constituent of marine systems, serve an indispensable function as primary producers, supporting the marine food web, contributing to carbon sequestration, and providing habitats that sustain biodiversity. This review focuses on the bioactive constituents of algae, including polysaccharides, polyphenols, polypeptides, and terpenoid compounds, and discusses their potential applications in treating immune-related diseases, as well as the mechanisms through which they modulate immune responses. The bioactive substances derived from algae, including polyphenols, bioactive peptides, terpenes, polysaccharides and other compounds, may play a preventive role by modulating allergic responses and reducing the incidence of inflammation and cancer.

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.

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.

Pro-resolving lipid mediators and therapeutic innovations in resolution of inflammation

This review summarizes findings presented at the 19th World Congress of Basic & Clinical Pharmacology 2023 (Glasgow, Scotland, July 3rd to 7th, 2023) from 8 speakers in the field of resolution of inflammation, resolution pharmacology and resolution biology. It is now accepted that the acute inflammatory response is protective to defend the host against infection or tissue injury. Acute inflammation is self-limited and programmed to be limited in space and time: this is achieved through endogenous resolution processes that ensure return to homeostasis. Resolution is brought about by agonist mediators that include specialized pro-resolving lipid mediators (SPMs) and pro-resolving proteins and peptides such as annexin A1 and angiotensin-(1-7), all acting to initiate anti-inflammatory and pro-resolving processes. If the inflammatory reaction remains unchecked through dysfunctional resolution mechanism, it can become chronic and contribute to a plethora of human diseases, including respiratory, cardiovascular, metabolic, allergic diseases, and arthritis. Herein, we discuss how non-resolving inflammation plays a role in the pathogenesis of these diseases. In addition to SPMs, we highlight the discovery, biosynthesis, biofunctions, and latest research updates on innovative therapeutics (including annexin-A1 peptide-mimetic RTP-026, small molecule FPR2 agonist BM-986235/LAR-1219, biased agonist for FPR1/FPR2 Cmpd17b, lipoxin mimetics AT-01-KG and AT-02-CT, melanocortin receptor agonist AP1189, gold nanoparticles, angiotensin-(1-7), and CD300a) that can promote resolution of inflammation directly or through modulation of SPMs production. Drug development strategies based on the biology of the resolution of inflammation can offer novel therapeutic means and/or add-on therapies for the treatment of chronic diseases.

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.

Omega-3 long chain fatty acids and their metabolites in pregnancy outcomes for the modulation of maternal inflammatory- associated causes of preterm delivery, chorioamnionitis and preeclampsia

Preterm birth is a major cause of perinatal complications and neonatal deaths. Furthermore, in the field of obstetrics many clinical entities like uterine contractions or the occurrence of pre- eclampsia remain to be serious complications during pregnancy and represent a major psychological, financial, and economic burden for society. Several published guidelines, studies and recommendations have highlighted the importance of supplementation of omega-3 long chain polyunsaturated fatty acids (PUFAs) during pregnancy. This narrative review aims at giving an overview on the modern perception of inflammatory processes and the role of specialized pro-resolving mediators (SPMs) in their resolution, especially in obstetrics. Additionally, we highlight the possible role of SPMs in the prevention of obstetric complications through oral supplementation using enriched marine oil nutritional's. The intake of PUFAs may result in an overall improvement of pregnancy outcomes by contributing to fetal brain growth and neurological development but more importantly though modulation of inflammation-associated pathologies. Especially the use of SPMs represents a promising approach for the management of obstetric and perinatal complications. SPMs are monohydroxylates derived from enriched marine oil nutritional's that involve certain pro-resolutive metabolites of omega-3 long chains PUFAs and may contribute to an attenuation of inflammatory diseases. This may be obtained through various mechanisms necessary for a proper resolution of inflammation such as the termination of neutrophil tissue infiltration, initiation of phagocytosis, downregulation of pro-inflammatory cytokines or tissue regeneration. In this way, acute and chronic inflammatory diseases associated with serious obstetrical complications can be modulated, which might contribute to an improved pregnancy outcome.

Synthesis of the methyl ester of 17(R/S)-Me-RvD5n-3 DPA and relief of postoperative pain in male mice

The synthesis and biological evaluation of 17(R/S)-Me-RvD5n-3 DPA, an analog of the specialized pro-resolving mediators RvD5 and RvD5n-3 DPA, are presented. The synthesis was successfully accomplished utilizing Midland Alpine borane reduction, Sonogashira cross-coupling and a one-pot hydrozirconation/iodination protocol. In vivo evaluation of RvD5, RvD5n-3 DPA and 17(R/S)-Me-RvD5n-3 DPA in a mouse model of fracture revealed that all three compounds inhibited postoperative pain in male mice, but not in female mice.

Docosahexaenoic Acid-Infused Core-Shell Fibrous Membranes for Prevention of Epidural Adhesions

Avoiding epidural adhesion following spinal surgery can reduce clinical discomfort and complications. As the severity of epidural adhesion is positively correlated with the inflammatory response, implanting a fibrous membrane after spinal surgery, which can act as a physical barrier to prevent adhesion formation while simultaneously modulates postoperative inflammation, is a promising approach to meet clinical needs. Toward this end, we fabricated an electrospun core-shell fibrous membrane (CSFM) based on polylactic acid (PLA) and infused the fiber core region with the potent natural anti-inflammatory compound docosahexaenoic acid (DHA). The PLA/DHA CSFM can continuously deliver DHA for up to 36 days in vitro and reduce the penetration and attachment of fibroblasts. The released DHA can downregulate the gene expression of inflammatory markers (IL-6, IL-1β, and TNF-α) in fibroblasts. Following an in vivo study that implanted a CSFM in rats subjected to lumbar laminectomy, the von Frey withdrawal test indicates the PLA/DHA CSFM treatment can successfully alleviate neuropathic pain-like behaviors in the treated rats, showing 3.60 ± 0.49 g threshold weight in comparison with 1.80 ± 0.75 g for the PLA CSFM treatment and 0.57 ± 0.37 g for the untreated control on day 21 post-implantation. The histological analysis also indicates that the PLA/DHA CSFM can significantly reduce proinflammatory cytokine (TNF-α and IL-1β) protein expression at the lesion and provide anti-adhesion effects, indicating its vital role in preventing epidural fibrosis by mitigating the inflammatory response.

Omega-3 fatty acids as a treatment option in periodontitis: Systematic review of preclinical studies

Background: Periodontitis presents as a chronic inflammatory disease that affects the gingival tissues and structures surrounding the tooth. However, the existing approaches for periodontitis do not allow complete control of the disease. In this regard, an active search is being carried out both in preclinical and clinical studies for new approaches based, among other things, on nutraceuticals. Aim: This systematic review aimed to summarize and systematize data from preclinical studies on the effects of the use of polyunsaturated omega-3 fatty acids in experimentally induced periodontitis. Methods: A systematic search for research articles was performed using electronic scientific databases. Only original in vivo experimental studies investigating the use of omega-3 polyunsaturated fatty acids in experimentally induced periodontitis were included. Quality and risk of bias assessment (Systematic Review Centre for Laboratory Animal Experimentation) and quality of evidence assessment (using the modified Grading of Recommendations Assessment, Development and Evaluation approach) were performed. Results: Nineteen studies were included in this systematic review. It has been shown that omega-3 polyunsaturated fatty acids may decrease the progression of periodontitis with amelioration of alveolar bone loss along with decreased pro-inflammatory response and inhibition of osteoclasts. Despite the promising results, most of the analyzed studies were characterized by low to moderate quality and a significant risk of bias. Conclusion: Based on the retrieved data, the possibility of extrapolating the obtained results to humans is limited, indicating the need for additional studies to elucidate the key patterns and mechanisms of action of omega-3 polyunsaturated fatty acids and their endogenous metabolites in experimentally induced periodontitis.

Inflammatory pathways and anti-inflammatory therapies in sickle cell disease

Sickle cell disease (SCD) is a monogenic disease, resulting from a single-point mutation, that presents a complex pathophysiology and high clinical heterogeneity. Inflammation stands as a prominent characteristic of SCD. Over the past few decades, the role of different cells and molecules in the regulation of the inflammatory process has been elucidated. In conjunction with the polymerization of hemoglobin S (HbS), intravascular hemolysis, which releases free heme, HbS, and hemoglobin-related damage-associated molecular patterns, initiates multiple inflammatory pathways that are not yet fully comprehended. These complex phenomena lead to a vicious cycle that perpetuates vaso-occlusion, hemolysis, and inflammation. To date, few inflammatory biomarkers can predict disease complications; conversely, there is a plethora of therapies that reduce inflammation in SCD, although clinical outcomes vary widely. Importantly, whether the clinical heterogeneity and complications are related to the degree of inflammation is not known. This review aims to further our understanding of the roles of main immune cells, and other inflammatory factors, as potential prognostic biomarkers for predicting clinical outcomes or identifying novel treatments for SCD.

A potent proresolving mediator 17R-resolvin D2 from human macrophages, monocytes, and saliva

Production of specialized proresolving mediators (SPMs) during the resolution phase in the acute inflammatory response is key to orchestrating complete resolution. Here, we uncovered a trihydroxy resolvin in fresh human saliva. We identified and determined its complete stereochemistry as 7S,16R,17R-trihydroxy-4Z,8E,10Z,12E,14E,19Z-docosahexaenoic acid (17R-RvD2) using total organic synthesis and matching of physical properties. The 17R-RvD2 was produced by activated human M2-like macrophages, M1-like macrophages, and human peripheral blood monocytes. 17R-RvD2 displayed potent proresolving functions (picomolar to nanomolar). Topical application of 17R-RvD2 on mouse ear skin reduced neutrophilic infiltration (~50%). 17R-RvD2 increased M2 markers CD206 and CD163 on human monocyte-derived macrophages and enhanced efferocytosis of senescent red blood cells by M2-like macrophages (EC50 ~ 2.6 × 10-14 M). In addition, 17R-RvD2 activated the RvD2 receptor and was equipotent to its epimer RvD2. 17R-RvD2 also significantly increased phagocytosis of Escherichia coli by human neutrophils. Together, these results establish the complete stereochemistry and potent proresolving functions of the previously unknown 17R-RvD2.

Disrupted balance between pro-inflammatory lipid mediators and anti-inflammatory specialized pro-resolving mediators is linked to hyperinflammation in patients with alcoholic hepatitis

Background

Alcoholic hepatitis (AH) is characterized by intense systemic and liver inflammation, posing significant risks of health complications and mortality. While inflammation is a crucial defense mechanism against injury and infection, its timely resolution is essential to prevent tissue damage and restore tissue homeostasis. The resolution of inflammation is primarily governed by specialized pro-resolving mediators (SPMs), lipid metabolites derived from w-6 and w-3 poly-unsaturated fatty acids (PUFAs). Currently, the balance between pro-inflammatory lipid mediators (PLMs) and SPMs in the w-6 and w-3 PUFA metabolic pathways and the impact of alcohol abstinence on profiles of PLMs and SPMs in AH patients are not well studied.

Methods

In this study, we used LC-MS/MS and ELISA to quantify levels of lipid mediators (LMs) and their precursors in the plasma samples from 58 AH patients, 29 heavy drinkers without overt liver diseases (HDCs), and 35 healthy controls (HCs). Subsequently, we assessed correlations of altered LMs with clinical parameters and inflammatory mediators. Furthermore, we conducted a longitudinal study to analyze the effects of alcohol abstinence on LMs over 6- and 12-month follow-ups.

Results

AH patients exhibited significantly higher plasma levels of w-6 PLMs (PGD2 and LTB4) and SPM RvE1 compared to HDCs or HCs. Conversely, the SPM LXA4 was significantly downregulated in AH patients. Some of these altered LMs were found to correlate with AH disease severity and various inflammatory cytokines. Particularly, the LTB4/LXA4 ratio was substantially elevated in AH patients relative to HDCs and HCs. This altered ratio displayed a positive correlation with the MELD score. Importantly, the majority of dysregulated LMs, particularly PLMs, were normalized following alcohol abstinence.

The resolvin D2 and omega-3 polyunsaturated fatty acid as a new possible therapeutic approach for inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are idiopathic disorders characterized by chronic gastrointestinal inflammation. Given conventional therapies' adverse effects and clinical failures, novel approaches are being investigated. Recent studies have highlighted the role of specialized pro-resolving lipid mediators (SPMs) in the active resolution of chronic inflammation. In this regard, omega-3 fatty acid-derived Resolvin D2 (RvD2) appears to play a protective role in the pathophysiology of IBD. Therefore, we characterized the RvD2 pathway and its receptor expression in the intestinal mucosa of experimental colitis induced by dextran sulfate sodium. We also evaluated the preventive impact of an omega-3-enriched diet and the therapeutic efficacy of RvD2 compared with anti-TNF-α treatment. We found an increase in TNFα and IL22 expression and decreased levels of enzymes involved in RvD2 biosynthesis, such as PLA2, 15-LOX, 5-LOX, and its receptor GPR18 in experimental colitis. Omega-3 supplementation reduced the Disease Activity Index (DAI), weight loss, colonic shortening, and inflammation. These results and the increased IL-10 transcriptional levels after RvD2 treatment suggest that this mediator attenuated experimental colitis. These results enhance our understanding of the molecular mechanisms involved in the exacerbated inflammatory response present in experimental colitis and suggest that RvD2 and its omega-3 precursor offer a promising therapeutic approach for IBD.

Circulating Protectin D1 and Neutrophils Extracellular Traps in the Diagnosis and Progression of Acute Pancreatitis

Purpose

Protectin D1 (PD1), a biologically active molecule derived from docosahexaenoic acid (DHA), plays a major role in the body's endogenous lipid-mediated inflammatory response. The study aims to explore the relationship between PD1, inflammatory response and the severity of acute pancreatitis (AP).

Patients and Methods

Sixty consecutive AP patients within 72h of disease onset were enrolled as the study group, a further thirty healthy people were enrolled as the control group. General demographics collected at the time of enrollment. Serum PD1, Citrullinated Histone 3 (CitH3), myeloperoxidase-Deoxyribonucleic acid (MPO-DNA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) level were measured in AP patients on enrollment day 0, day 1, day 3 and day 7. Meanwhile, the Acute Physiology and Chronic Health evaluation II (APACHE II) scores, Sequential Organ Failure Assessment (SOFA) scores were also evaluated on day 0, day 1, day 3 and day 7.

Results

AP was severe in 29 patients (48.3%), moderately severe acute pancreatitis (MSAP) was found in 9 patients (15%), and mild acute pancreatitis (MAP) was found in 22 patients (36.7%). The level of PD1, CitH3 and MPO-DNA were statistically significantly higher in AP patients than in the healthy population. Serum PD1, CitH3 and MPO-DNA concentration increased with AP severity. In AP patients, PD1 has a strong linear association with TNF-α, CitH3 and MPO-DNA. The AUC for SAP predicted by PD1 was 0.938. The calculated cut-off point for prognosis SAP is 7.94 pg/mL. The AUC for infected pancreatic necrosis (IPN) predicted by PD1 was 0.836 and the cut-off point was 8.65 pg/mL. The AUC for organ failure (OF) predicted by PD1 was 0.719 and the cut-off point was 7.94 pg/mL.

Conclusion

PD1 is associated with both the presence of AP and the severity of pancreatitis.

The dual role of lipids in chronic kidney disease: Pathogenic culprits and therapeutic allies

Chronic kidney disease (CKD) is a significant health burden, with rising incidence and prevalence, attributed in part to increasing obesity and diabetes rates. Lipid accumulation in the kidney parenchyma and chronic, low-grade inflammation are believed to significantly contribute to the development and progression of CKD. The effect of dysregulated kidney lipid metabolism in CKD progression, including altered cholesterol and fatty acid metabolism contribute to glomerular and tubular cell injury through the activation of oxidative stress and inflammatory signalling cascades. In contrast, classes of endogenous specialized pro-resolving lipid mediators (SPMs) have been described that act to limit the inflammatory response and promote the resolution of inflammation. This review highlights our current understanding of how lipids can cause damage within the kidney, and classes of protective lipid metabolites that offer therapeutic benefits.

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.

Spatially heterogeneous lipid dysregulation in tuberculous meningitis

Tuberculous (TB) meningitis is the deadliest form of extrapulmonary TB which disproportionately affects children and immunocompromised individuals. Studies in pulmonary TB have shown that Mycobacterium tuberculosis can alter host lipid metabolism to evade the immune system. Cholesterol lowering drugs (i.e., statins) reduce the risk of infection, making them a promising host-directed therapy in pulmonary TB. However, the effect of M. tuberculosis infection on the young or adult brain lipidome has not been studied. The brain is the second-most lipid-rich organ, after adipose tissue, with a temporally and spatially heterogeneous lipidome that changes from infancy to adulthood. The young, developing brain in children may be uniquely vulnerable to alterations in lipid composition and homeostasis, as perturbations in cholesterol metabolism can cause developmental disorders leading to intellectual disabilities. To begin to understand the alterations to the brain lipidome in pediatric TB meningitis, we utilized our previously published young rabbit model of TB meningitis and applied mass spectrometry (MS) techniques to elucidate spatial differences. We used matrix assisted laser desorption/ionization-MS imaging (MALDI-MSI) and complemented it with region-specific liquid chromatography (LC)-MS/MS developed to identify and quantify sterols and oxysterols difficult to identify by MALDI-MSI. MALDI-MSI revealed several sphingolipids, glycerolipids and glycerophospholipids that were downregulated in brain lesions. LC-MS/MS revealed the downregulation of cholesterol, several sterol intermediates along the cholesterol biosynthesis pathway and enzymatically produced oxysterols as a direct result of M. tuberculosis infection. However, oxysterols produced by oxidative stress were increased in brain lesions. Together, these results demonstrate significant spatially regulated brain lipidome dysregulation in pediatric TB meningitis.

Eicosanoids Signals in SARS-CoV-2 Infection: A Foe or Friend

SARS-CoV-2 mediated infection instigated a scary pandemic state since 2019. They created havoc comprising death, imbalanced social structures, and a wrecked global economy. During infection, the inflammation and associated cytokine storm generate a critical pathological situation in the human body, especially in the lungs. By the passage of time of infection, inflammatory disorders, and multiple organ damage happen which might lead to death, if not treated properly. Until now, many pathological parameters have been used to understand the progress of the severity of COVID-19 but with limited success. Bioactive lipid mediators have the potential of initiating and resolving inflammation in any disease. The connection between lipid storm and inflammatory states of SARS-CoV-2 infection has surfaced and got importance to understand and mitigate the pathological states of COVID-19. As the role of eicosanoids in COVID-19 infection is not well defined, available information regarding this issue has been accumulated to address the possible network of eicosanoids related to the initiation of inflammation, promotion of cytokine storm, and resolution of inflammation, and highlight possible strategies for treatment and drug discovery related to SARS-CoV-2 infection in this study. Understanding the involvement of eicosanoids in exploration of cellular events provoked by SARS-CoV-2 infection has been summarized as an important factor to deescalate any upcoming catastrophe imposed by the lethal variants of this micro-monster. Additionally, this study also recognized the eicosanoid based drug discovery, treatment, and strategies for managing the severity of SARS-COV-2 infection.

PUFA and intrahepatic cholestasis of pregnancy: a two-sample Mendelian randomisation analysis

This study aimed to explore the potential causal association between PUFA and the risk of intrahepatic cholestasis of pregnancy (ICP) using Mendelian randomisation (MR) analysis. A two-sample MR analysis was conducted utilising large-scale European-based genome-wide association studies summary databases. The primary MR analysis was carried out using the inverse variance-weighted (IVW) method, complemented by other methods such as MR-egger, weighted-median and weighted mode. Sensitivity analysis was also performed to validate the robustness of the findings. Results indicated a 31 % reduced risk of ICP for every 1 standard deviation (sd) increase in n-3 fatty acids levels (OR = 0·69, 95 % CI: 0·54, 0·89, P = 0·004) and in the ratio of n-3 fatty acids to total fatty acids (OR = 0·69, 95 % CI: 0·53, 0·91, P = 0·008). Conversely, there was a 51 % increased risk of ICP for every 1 sd increase in the ratio of n-6 fatty acids to n-3 fatty acids (OR = 1·51, 95 % CI: 1·20, 1·91, P < 0·001) and a 138 % increased risk for every 1 sd increase in the ratio of linoleic fatty acids to total fatty acids (OR = 2·38, 95 % CI: 1·55, 3·66, P < 0·001). The findings suggest that n-3 fatty acids may have a protective effect against the risk of ICP, while n-6 fatty acids and linoleic fatty acids could be potential risk factors for ICP. The supplementation of n-3 fatty acids, as opposed to n-6 fatty acids, could be a promising strategy for the prevention and management of ICP.

Omega-3 long-chain polyunsaturated fatty acids and their bioactive lipids: A strategy to improve resistance to respiratory tract infectious diseases in the elderly?

Age-related changes in organ function, immune dysregulation, and the effects of senescence explain in large part the high prevalence of infections, including respiratory tract infections in older persons. Poor nutritional status in many older persons increases susceptibility to infection and worsens prognosis. Interestingly, there is an association between the amount of saturated fats in the diet and the rate of community-acquired pneumonia. Polyunsaturated fatty acids, particularly omega-3 long chain polyunsaturated fatty acids (ω-3 LC-PUFAs) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have well-known anti-inflammatory, immunomodulatory, and antimicrobial effects, which may, in theory, be largely induced by PUFAs-derived lipids such as specialized pro-resolving mediators (SPMs). In adults, preliminary results of studies show that ω-3 LC-PUFAs supplementation can lead to SPM generation. SPMs have a crucial role in the resolution of inflammation, a factor relevant to survival from infection independent of the pathogen’s virulence. Moreover, the immune system of older adults appears to be more sensitive to ω-3 PUFAs. This review explores the effects of ω-3 LC-PUFAs, and PUFA bioactive lipid-derived SPMs in respiratory tract infections and the possible relevance of these data to infectious disease outcomes in the older population. The hypothesis that PUFAs have beneficial effects via SPM generation will need to be confirmed by animal experiments and patient-derived data.

Phospholipids, Sphingolipids, and Cholesterol-Derived Lipid Mediators and Their Role in Neurological Disorders

Neural membranes are composed of phospholipids, sphingolipids, cholesterol, and proteins. In response to cell stimulation or injury, the metabolism of lipids generates various lipid mediators, which perform many cellular functions. Thus, phospholipids release arachidonic acid or docosahexaenoic acid from the sn-2 position of the glycerol moiety by the action of phospholipases A2. Arachidonic acid is a precursor for prostaglandins, leukotrienes, thromboxane, and lipoxins. Among these mediators, prostaglandins, leukotrienes, and thromboxane produce neuroinflammation. In contrast, lipoxins produce anti-inflammatory and pro-resolving effects. Prostaglandins, leukotrienes, and thromboxane are also involved in cell proliferation, differentiation, blood clotting, and blood vessel permeability. In contrast, DHA-derived lipid mediators are called specialized pro-resolving lipid metabolites (SPMs). They include resolvins, protectins, and maresins. These mediators regulate immune function by producing anti-inflammatory, pro-resolving, and cell protective effects. Sphingolipid-derived metabolites are ceramide, ceramide1-phosphate, sphingosine, and sphingosine 1 phosphate. They regulate many cellular processes, including enzyme activities, cell migration and adhesion, inflammation, and immunity. Cholesterol is metabolized into hydroxycholesterols and 7-ketocholesterol, which not only disrupts membrane fluidity, but also promotes inflammation, oxidative stress, and apoptosis. These processes lead to cellular damage.

Insights into geriatric health: primary sarcopenia and innate immunity dynamics, examining SARC-F, serum TLR 4, TLR 9, and resolvin levels

The aim of this study is to evaluate the relationship between serum TLR (Toll Like Receptor) 4, 9 and Resolvin E1 levels and primary sarcopenia in geriatric patients and to compare the diagnostic accuracy of these biomarkers with the SARC-F score. A total of 88 patients aged 65 years and older were evaluated in the study. Comorbidities and geriatric syndromes were identified and patients with secondary sarcopenia were excluded. EWGSOP2 criteria were used as diagnostic criteria for sarcopenia and SARC-F questionnaire was used to find individuals at risk for sarcopenia. Serum TLR 4, 9 and Resolvin E1 levels were analyzed by ELISA. There were no significant differences between the two groups in terms of age and gender (p = 0.654 and p = 1.000, respectively). SARC-F, serum TLR 9 and Resolvin E1 were significantly higher in the sarcopenia group compared to the non-sarcopenia group (p < 0.001, p < 0.001 and p = 0.040, respectively). Statistically significant parameters were evaluated by multiple regression analysis. TLR 9 and SARC-F score were both found to be associated with sarcopenia in multivariate logistic regression analysis [Odds ratio (OR) 3145, (95%) confidence interval (CI) 5.9-1,652,888.3, p = 0.012; OR 4.788, (95%) CI 2.148-10.672, p < 0.001, respectively]. ROC curve analysis showed that the area under the ROC curve (AUC) for TLR 9 and SARC-F was 0.896 (p < 0.001) and 0.943 (p < 0.001), respectively. Although this study supports the use of the SARC-F questionnaire in daily practice, serum TLR 9 levels may be an alternative to SARC-F in cases where SARC-F is not feasible.

Resolvins D5 and D1 undergo phase II metabolism by uridine 5'-diphospho-glucuronosyltransferases

Specialized pro-resolving mediators (SPMs) are oxidized lipid mediators that have been shown to resolve inflammation in cellular and animal models as well as humans. SPMs and their biological precursors are even commercially available as dietary supplements. It has been understood for more than forty years that pro-inflammatory oxidized lipid mediators, including prostaglandins and leukotrienes, are rapidly inactivated via metabolism. Studies on the metabolism of SPMs are, however, limited. Herein, we report that resolvin D5 (RvD5) and resolvin D1 (RvD1), well-studied SPMs, are readily metabolized by human liver microsomes (HLM) to glucuronide conjugated metabolites. We further show that this transformation is catalyzed by specific uridine 5'-diphospho-glucuronosyltransferase (UGT) isoforms. Additionally, we demonstrate that RvD5 and RvD1 metabolism by HLM is influenced by non-steroidal anti-inflammatory drugs (NSAIDs), which can act as UGT inhibitors through cyclooxygenase-independent mechanisms. The results from these studies highlight the importance of considering metabolism, as well as factors that influence metabolic enzymes, when seeking to quantify SPMs in vivo.

Targeting cyclooxygenase-2 for chemoprevention of inflammation-associated intestinal carcinogenesis: An update

Mounting evidence from preclinical and clinical studies suggests that persistent inflammation functions as a driving force in the journey to cancer. Cyclooxygenase-2 (COX-2) is a key enzyme involved in inflammatory signaling. While being transiently upregulated upon inflammatory stimuli, COX-2 has been found to be consistently overexpressed in human colorectal cancer and several other malignancies. The association between chronic inflammation and cancer has been revisited: cancer can arise when inflammation fails to resolve. Besides its proinflammatory functions, COX-2 also catalyzes the production of pro-resolving as well as anti-inflammatory metabolites from polyunsaturated fatty acids. This may account for the side effects caused by long term use of some COX-2 inhibitory drugs during the cancer chemopreventive trials. This review summarizes the latest findings highlighting the dual functions of COX-2 in the context of its implications in the development, maintenance, and progression of cancer.

Role of sirtuins in sepsis and sepsis-induced organ dysfunction: A review

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis causes a high mortality rate and current treatment focuses on supportive therapies but lacks specific therapeutic targets. Notably, sirtuins (SIRTs) shows potential clinical application in the treatment of sepsis. It has been demonstrated that SIRTs, the nicotinamide adenine dinucleotide+(NAD+)-dependent deacetylases that regulate key signaling pathways in eukaryotes and prokaryotes, are involved in a variety of biological processes. To date, seven mammalian yeast Sir2 homologs have been identified. SIRTs can regulate inflammation, oxidative stress, apoptosis, autophagy, and other pathways that play important roles in sepsis-induced organ dysfunction. However, the existing studies on SIRTs in sepsis are too scattered, and there is no relevant literature to integrate them. This review innovatively summarizes the different mechanisms of SIRTs in sepsis organ dysfunction according to the different systems, and focuses on SIRT agonists, inhibitors, and targeted drugs that have been proved to be effective in the treatment of sepsis, so as to integrate the clinical research and basic research closely. We searched PubMed for all literature related to SIRTs and sepsis since its inception using the following medical subject headings: sirtuins, SIRTs, and sepsis. Data on the mechanisms of SIRTs in sepsis-induced organ damage and their potential as targets for disease treatment were extracted.

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.

Structural basis for the access and binding of resolvin D1 (RvD1) to formyl peptide receptor 2 (FPR2/ALX), a class A GPCR

Inflammation is essential to the body's defense against tissue injury and microbial invasion. However, uncontrolled inflammation is highly detrimental and can result in chronic inflammatory diseases such as asthma, cancer, obesity, and diabetes. An increasing body of evidence suggests that specialized pro-resolving lipid mediators (SPMs), such as resolvins, are actively involved in critical cellular events that drive the resolution of inflammation and a return to homeostasis. An imbalance caused by insufficient SPMs can result in the unsuccessful resolution of inflammation. The D-series resolvins (metabolites of docosahexaenoic acid), such as resolvin D1 (RvD1) and resolvin D2 (RvD2), carry out their pro-resolving functions by directly binding to class A G protein-coupled receptors FPR2/ALXR and GPR32, and GPR18, respectively. We recently demonstrated that RvD1 and RvD2 preferentially partition and accumulate at the polar headgroup regions of the membrane. However, the mechanistic detail of how RvD1 gains access to the FPR2 binding site from a surrounding membrane environment remains unknown. In this study, we used classical MD and well-tempered metadynamics simulations to examine the structural basis for the access and binding of RvD1 to its target receptor from aqueous and membrane environments. The results offer valuable insights into the access path, potential binding pose, and key residue interactions essential for the access and binding of RvD1 to FPR2/ALXR and may help in identifying small molecule therapeutics as a possible treatment for inflammatory disorders.

Biosynthesis of resolvin D1, resolvin D2, and RCTR1 from 7,8(S,S)-epoxytetraene in human neutrophils and macrophages

While the acute inflammatory response to harmful stimuli is protective, unrestrained neutrophil swarming drives collateral tissue damage and inflammation. Biosynthesized from omega-3 essential polyunsaturated fatty acids, resolvins are a family of signaling molecules produced by immune cells within the resolution phase to orchestrate return to homeostasis. Understanding the mechanisms that govern biosynthesis of these potent molecules gives insight into stimulating endogenous resolution and offers fresh opportunities for preventing and treating excessive inflammation. In this report, using materials prepared by total synthesis and liquid chromatography and tandem mass spectrometry-based matching studies, we established the role of 7,8(S,S)-epoxytetraene intermediate in the biosynthesis of resolvin D1, resolvin D2, and the resolvin conjugate in tissue regeneration (RCTR1) by human phagocytes. We demonstrated that this 7,8(S,S)-epoxy-containing intermediate is directly converted to resolvin D2 by human M2-like macrophages and to resolvin D1 and RCTR1 by human macrophages, neutrophils, and peripheral blood mononuclear cells. In addition, both human recombinant soluble epoxide hydrolase (sEH) and the glutathione S-transferase leukotriene C4 synthase (LTC4S) each catalyze conversion of this epoxide to resolvin D1 and RCTR1, respectively. MS3 ion-trap scans and isotope incorporation of 18O from H218O with sEH indicated that the oxygen atom at C-8 in resolvin D1 is derived from water. Results from molecular docking simulations with biosynthetic precursor 17S-hydroperoxy-4,7,10,13,19-cis-15-trans-docosahexaenoic acid and the epoxy intermediate were consistent with 5-lipoxygenase production of resolvin D1. Together, these results give direct evidence for the role of resolvin 7,8(S,S)-epoxytetraene intermediate in the endogenous formation of resolution-phase mediators resolvin D1, resolvin D2, and RCTR1 by human phagocytes.

Resolvins protect against diabetes-induced colonic oxidative stress, barrier dysfunction, and associated diarrhea via the HO-1 pathway

Diabetes is associated with increased oxidative stress, leading to altered tight junction formation and increased apoptosis in colonic epithelial cells. These changes may lead to intestinal barrier dysfunction and corresponding gastrointestinal symptoms in patients with diabetes, including diarrhea. The aim of this study was to characterize the effect and mechanism of Resolvin D1 (RvD1) on diabetes-induced oxidative stress and barrier disruption in the colon. Mice with streptozotocin-induced diabetes were treated with RvD1 for 2 weeks, then evaluated for stool frequency, stool water content, gut permeability, and colonic transepithelial electrical resistance as well as production of reactive oxygen species (ROS), apoptosis, and expression of tight junction proteins Zonula Occludens 1 (ZO-1) and occludin. The same parameters were assessed in human colonoid cultures subjected to elevated glucose. We found that RvD1 treatment did not affect blood glucose, but normalized stool water content and prevented intestinal barrier dysfunction, epithelial oxidative stress, and apoptosis. RvD1 also restored ZO-1 and occludin expression in diabetic mice. RvD1 treatment increased phosphorylation of Akt and was accompanied by a 3.5-fold increase in heme oxygenase-1 (HO-1) expression in the epithelial cells. The protective effects of RvD1 were blocked by ZnPP, a competitive inhibitor of HO-1. Similar findings were observed in RvD1-treated human colonoid cultures subjected to elevated glucose. In conclusion, Oxidative stress in diabetes results in mucosal barrier dysfunction, contributing to the development of diabetic diarrhea. Resolvins prevent ROS-mediated mucosal injury and protect gut barrier function by intracellular PI3K/Akt activation and subsequent HO-1 upregulation in intestinal epithelial cells. These actions result in normalizing stool frequency and stool water content in diabetic mice, suggesting that resolvins may be useful in the treatment of diabetic diarrhea.

Fish Oil Containing Pro-Resolving Mediators Enhances the Antioxidant System and Ameliorates LPS-Induced Inflammation in Human Bronchial Epithelial Cells

Fish oil, renowned for its high content of omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has gained considerable attention for its potential health benefits. EPA and DHA exhibit anti-inflammatory effects by promoting the production of specialized pro-resolving mediators (SPMs), such as resolvins and protectins. Fish oil has been studied for its potential to reduce bronchial inflammation, a key feature of respiratory conditions like asthma and COPD. This study investigates the cellular mechanisms of fish oil in an in vitro model of lung inflammation using lipopolysaccharide (LPS) on a healthy human bronchial epithelium cell line. LPS exposure for 24 h reduced cell viability, elevated reactive oxygen species (ROS), depleted glutathione (GSH), and induced mitochondrial depolarization, indicating oxidative stress and inflammation. Fish oil administration significantly mitigated ROS production, prevented GSH depletion, and reduced mitochondrial depolarization. This was associated with the upregulation of the endogenous antioxidant system, evidenced by restored GSH levels and the increased gene expression of glutathione peroxidase (GPX), catalase (CAT), superoxide dismutase 1 (SOD1), and superoxide dismutase 2 (SOD2). Fish oil also suppressed IL-6 and IL-1β expression and increased anti-inflammatory cytokine IL-10 expression. Furthermore, fish oil upregulated the expression of pro-resolving mediator receptors, suggesting a role in inflammation resolution. These findings highlight the potential of fish oil supplementation as a preventive measure against pulmonary diseases characterized by unresolved inflammation such as lung inflammation.

Omega-3 Polyunsaturated Fatty Acids in Depression

Omega-3 polyunsaturated fatty acids have received considerable attention in the field of mental health, in particular regarding the treatment of depression. This review presents an overview of current research on the role of omega-3 fatty acids in the prevention and treatment of depressive disorders. The existing body of evidence demonstrates that omega-3 fatty acids, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have antidepressant effects that can be attributed to their modulation of neuroinflammation, neurotransmitter function, and neuroplasticity. Nevertheless, clinical trials of omega-3 supplementation have yielded inconsistent results. Some studies have demonstrated significant reductions in depressive symptoms following omega-3 treatment, whereas others have shown minimal to no beneficial impact. A range of factors, encompassing dosage, the ratio of EPA to DHA, and baseline nutritional status, have been identified as having a potential impact on the noted results. Furthermore, it has been suggested that omega-3 fatty acids may act as an adjunctive treatment for those undergoing antidepressant treatment. Notwithstanding these encouraging findings, discrepancies in study designs and variability in individual responses underscore the necessity of further research in order to establish uniform, standardized guidelines for the use of omega-3 fatty acids in the management of depressive disorders.

Resolution of inflammation, an active process to restore the immune microenvironment balance: A novel drug target for treating arterial hypertension

The resolution of inflammation, the other side of the inflammatory response, is defined as an active and highly coordinated process that promotes the restoration of immune microenvironment balance and tissue repair. Inflammation resolution involves several key processes, including dampening proinflammatory signaling, specialized proresolving lipid mediator (SPM) production, nonlipid proresolving mediator production, efferocytosis and regulatory T-cell (Treg) induction. In recent years, increasing attention has been given to the effects of inflammation resolution on hypertension. Furthermore, our previous studies reported the antihypertensive effects of SPMs. Therefore, in this review, we aim to summarize and discuss the detailed association between arterial hypertension and inflammation resolution. Additional, the association between gut microbe-mediated immune and hypertension is discussed. This findings suggested that accelerating the resolution of inflammation can have beneficial effects on hypertension and its related organ damage. Exploring novel drug targets by focusing on various pathways involved in accelerating inflammation resolution will contribute to the treatment and control of hypertensive diseases in the future.

15-epi-lipoxin A5 promotes neutrophil exit from exudates for clearance by splenic macrophages

Specialized proresolving mediators (SPMs) promote local macrophage efferocytosis but excess leukocytes early in inflammation require additional leukocyte clearance mechanism for resolution. Here, neutrophil clearance mechanisms from localized acute inflammation were investigated in mouse dorsal air pouches. 15-HEPE (15-hydroxy-5Z,8Z,11Z,13E,17Z-eicosapentaenoic acid) levels were increased in the exudates. Activated human neutrophils converted 15-HEPE to lipoxin A5 (5S,6R,15S-trihydroxy-7E,9E,11Z,13E,17Z-eicosapentaenoic acid), 15-epi-lipoxin A5 (5S,6R,15R-trihydroxy-7E,9E,11Z,13E,17Z-eicosapentaenoic acid), and resolvin E4 (RvE4; 5S,15S-dihydroxy-6E,8Z,11Z,13E,17Z-eicosapentaenoic acid). Exogenous 15-epi-lipoxin A5, 15-epi-lipoxin A4 and a structural lipoxin mimetic significantly decreased exudate neutrophils and increased local tissue macrophage efferocytosis, with comparison to naproxen. 15-epi-lipoxin A5 also cleared exudate neutrophils faster than the apparent local capacity for stimulated macrophage efferocytosis, so the fate of exudate neutrophils was tracked with CD45.1 variant neutrophils. 15-epi-lipoxin A5 augmented the exit of adoptively transferred neutrophils from the pouch exudate to the spleen, and significantly increased splenic SIRPa+ and MARCO+ macrophage efferocytosis. Together, these findings demonstrate new systemic resolution mechanisms for 15-epi-lipoxin A5 and RvE4 in localized tissue inflammation, which distally engage the spleen to activate macrophage efferocytosis for the clearance of tissue exudate neutrophils.

Resolvin D2-induced reparative dentin and pulp stem cells after pulpotomy in a rat model

Introduction

Vital pulp therapy (VPT) is performed to preserve dental pulp. However, the biocompatibility of the existing materials is of concern. Therefore, novel materials that can induce pulp healing without adverse effects need to be developed. Resolvin D2 (RvD2), one of specialized pro-resolving mediators, can resolve inflammation and promote the healing of periapical lesions. Therefore, RvD2 may be suitable for use in VPT. In the present study, we evaluated the efficacy of RvD2 against VPT using in vivo and in vitro models.

Methods

First molars of eight-week-old male Sprague-Dawley rats were used for pulpotomy. They were then divided into three treatment groups: RvD2, phosphate-buffered saline, and calcium hydroxide groups. Treatment results were assessed using radiological, histological, and immunohistochemical (GPR18, TNF-α, Ki67, VEGF, TGF-β, CD44, CD90, and TRPA1) analyses. Dental pulp-derived cells were treated with RvD2 in vitro and analyzed using cell-proliferation and cell-migration assays, real-time PCR (Gpr18, Tnf-α, Il-1β, Tgf-β, Vegf, Nanog, and Trpa1), ELISA (VEGF and TGF-β), immunocytochemistry (TRPA1), and flow cytometry (dental pulp stem cells: DPSCs).

Results

The formation of calcified tissue in the pulp was observed in the RvD2 and calcium hydroxide groups. RvD2 inhibited inflammation in dental pulp cells. RvD2 promoted cell proliferation and migration and the expression of TGF-β and VEGF in vitro and in vivo. RvD2 increased the number of DPSCs. In addition, RvD2 suppressed TRPA1 expression as a pain receptor.

Conclusion

RvD2 induced the formation of reparative dentin, anti-inflammatory effects, and decreased pain, along with the proliferation of DPSCs via the expression of VEGF and TGF-β, on the pulp surface in pulpotomy models.

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.

Biology and Total Synthesis of n-3 Docosapentaenoic Acid-Derived Specialized Pro-Resolving Mediators

Research over the last 25 years related to structural elucidations and biological investigations of the specialized pro-resolving mediators has spurred great interest in targeting these endogenous products in total synthesis. These lipid mediators govern the resolution of inflammation as potent and stereoselective agonists toward individual G-protein-coupled receptors, resulting in potent anti-inflammatory activities demonstrated in many human disease models. Specialized pro-resolving mediators are oxygenated polyunsaturated products formed in stereoselective and distinct biosynthetic pathways initiated by various lipoxygenase and cyclooxygenase enzymes. In this review, the reported stereoselective total synthesis and biological activities of the specialized pro-resolving mediators biosynthesized from the polyunsaturated fatty acid n-3 docosapentaenoic acid are presented.

Nutritional interventions as modulators of the disease activity for idiopathic inflammatory myopathies: a scoping review

Idiopathic inflammatory myopathies (IIMs) are chronic, autoimmune connective tissue diseases associated with significant morbidity and disability. Nutrients can activate the immune system and contribute to chronic low-grade inflammation (LGI). Chronic muscle inflammation leads to imbalanced pro-inflammatory and anti-inflammatory cytokines, causing inadequate nutrition, weight loss and muscle weakness during a negative cycle. Owing to its potential to modulate LGI in various diseases, the Mediterranean diet (Med Diet) has been extensively studied. This scoping review explores the nutritional implications and recommendations of the Med Diet as a treatment for immune-mediated diseases, focusing on the gaps in IIM nutritional interventions. A comprehensive literature search of the MEDLINE and EBSCO databases between September 2018 and December 2022 was performed. We identified that the Med Diet and its specific components, such as omega-3 (nω3) fatty acids, vitamin D and antioxidants, play a role in the dietary treatment of connective tissue-related autoimmune diseases. Nutritional interventions have demonstrated potential for modulating disease activity and warrant further exploration of IIMs through experimental studies. This review introduces a dietary therapeutic approach using the Med Diet and related compounds to regulate chronic inflammatory processes in IIMs. However, further clinical studies are required to evaluate the efficacy of the Med Diet in patients with IIMs. Emphasising a clinical-nutritional approach, this study encourages future research on the anti-inflammatory effects of the Med Diet on IIMs. This review highlights potential insights for managing and treating these conditions using a holistic approach.