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

Icosapent ethyl in cardiovascular prevention: Resolution of inflammation through the eicosapentaenoic acid - resolvin E1 - ChemR23 axis

Cardiovascular outcome trials on omega-3 fatty acids have generated contradictory results but indicate a dose-dependent beneficial effect of eicosapentaenoic acid (EPA). Beneficial cardiovascular effects of EPA may in addition to triglyceride lowering be mediated through alternative mechanisms of action. In this review, the link between EPA and a resolution of atherosclerotic inflammation is addressed. EPA is a substrate for the enzymatic metabolism into the lipid mediator resolvin E1 (RvE1), which activates the receptor ChemR23 to transduce an active resolution of inflammation. This has been shown to dampen the immune response and provide atheroprotective responses in different models. The intermediate EPA metabolite 18-HEPE emerges as a biomarker of EPA metabolism towards proresolving mediators in observational studies. Genetic variations within the EPA-RvE1-ChemR23 axis affecting the response to EPA may open up for precision medicine to identify responders and non-responders to EPA and fish oil supplementation. In conclusion, activation of the EPA-RvE1-ChemR23 axis towards a resolution of inflammation may contribute to beneficial effects in cardiovascular prevention.

Measuring brain docosahexaenoic acid turnover as a marker of metabolic consumption

Docosahexaenoic acid (DHA, 22:6n-3) accretion in brain phospholipids is critical for maintaining the structural fluidity that permits proper assembly of protein complexes for signaling. Furthermore, membrane DHA can by released by phospholipase A₂ and act as substrate for synthesis of bioactive metabolites that regulate synaptogenesis, neurogenesis, inflammation, and oxidative stress. Thus, brain DHA is consumed through multiple pathways including mitochondrial β-oxidation, autoxidation to neuroprostanes, as well as enzymatic synthesis of bioactive metabolites including oxylipins, synaptamide, fatty-acid amides, and epoxides. By using models developed by Rapoport and colleagues, brain DHA loss has been estimated to be 0.07-0.26 μmol DHA/g brain/d. Since β-oxidation of DHA in the brain is relatively low, a large portion of brain DHA loss may be attributed to synthesis of autoxidative and bioactive metabolites. In recent years, we have developed a novel application of compound specific isotope analysis to trace DHA metabolism. By the use of natural abundance in ¹³C-DHA in food supply, we are able to trace brain phospholipid DHA loss in free-living mice with estimates ranging from 0.11 to 0.38 μmol DHA/g brain/d, in reasonable agreement with previous methods. This novel fatty acid metabolic tracing methodology should improve our understanding of the factors that regulate brain DHA metabolism.

Resolvin D1 modulates periodontal ligament fibroblast function

BACKGROUND

The resolution of inflammation is an active process mediated by specialized lipid mediators called lipoxins and resolvins. Periodontal ligament fibroblasts (PDLFs) play a significant role in periodontal regeneration. The purpose of the current study was to determine the impact of resolvin D1 (RvD1) on human PDLF cell wound healing and proliferation, receptor expression (G-protein-coupled receptor 32 [GPR32] and formyl peptide receptor 2 [ALX/FPR2]), and cytokine expression and release.

METHODS

PDLFs were stimulated with interleukin-1β (IL-1β) (500 pg/ml) with and without RvD1 (100 nM). RvD1 receptor expression was determined by quantitative real-time polymerase chain reaction (qPCR), immunofluorescence microscopy, and fluorescence-activated cell sorting. Wound closure was measured by a scratch assay, and proliferation was determined by bromodeoxyuridine incorporation. Interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemoattractant protein-1, cyclooxygenase-2, matrix metalloproteinases-1, -2, and -3 (MMP-1, -2, and -3), tissue inhibitors of metalloproteinases-1 and -2 (TIMP-1 and -2), prostaglandin E2, and osteoprotegerin (OPG) gene expression and production were measured using qPCR and Western blotting, multiplex immunoassay, and enzyme-linked immunosorbent assay.

RESULTS

PDLF expressed GPR32 and ALX/FPR2. RvD1 reversed IL-1β-induced inhibition of wound healing and proliferation of PDLF. IL-1β also induced the production of proinflammatory cytokines and MMPs. This effect was reversed by RvD1. RvD1 reversed IL-1β-induced inhibition of TIMP-1, TIMP-2, and OPG.

CONCLUSION

The data suggested that RvD1 has a pro-wound healing, proliferative, and anti-inflammatory impact on the PDLF that favors periodontal regeneration.

Protective effects of resolvin D1 in Pseudomonas aeruginosa keratitis

PURPOSE

Here, we explored the protective effects of resolvin D1 (RvD1) in Pseudomonas aeruginosa (PA) keratitis.

METHODS

C57BL/6 (B6) mice were used as an animal model of PA keratitis. Plate counting and clinical scores were used to assess the severity of the infection and the therapeutic effects of RvD1 in the model. Myeloperoxidase assay was used to detect neutrophil infiltration and activity. Quantitative PCR (qPCR) was used to examine the expression of proflammatory and anti-inflammatory mediators. Immunofluorescence staining and qPCR were performed to identify macrophage polarization.

RESULTS

RvD1 treatment alleviated PA keratitis severity by decreasing corneal bacterial load and inhibiting neutrophil infiltration in the mouse model. Furthermore, RvD1 treatment decreased mRNA levels of TNF-α, IFN-γ, IL-1β, CXCL1, and S100A8/9 while increasing those of IL-1RA, IL-10, and TGF-β1. RvD1 treatment also reduced the aggregation of M1 macrophages and increased that of M2 macrophages. RvD1 provided an auxiliary effect in gatifloxacin-treated mice with PA keratitis.

CONCLUSION

Based on these findings, RvD1 may improve the prognosis of PA keratitis by inhibiting neutrophil recruitment and activity, dampening the inflammatory response, and promoting M2 macrophage polarization. Thus, RvD1 may be a potential complementary therapy for PA keratitis.

Recent Advances in Apical Periodontitis Treatment: A Narrative Review

Apical periodontitis is an inflammatory response caused by pulp infection. It induces bone resorption in the apical and periapical regions of the tooth. The most conservative approach to treat this condition is nonsurgical endodontic treatment. However, clinical failure has been reported with this approach; thus, alternative procedures are required. This review highlights recent literature regarding advanced approaches for the treatment of apical periodontitis. Various therapies, including biological medications, antioxidants, specialized pro-resolving lipid mediators, and stem cell therapy, have been tested to increase the success rate of treatment for apical periodontitis. Some of these approaches remain in the in vivo phase of research, while others have just entered the translational research phase to validate clinical application. However, a detailed understanding of the molecular mechanisms that occur during development of the immunoinflammatory reaction in apical periodontitis remains unclear. The aim of this review was to summarize advanced approaches for the treatment of apical periodontitis. Further research can confirm the potential of these alternative nonsurgical endodontic treatment approaches.

Dysregulation of Resolvin E1 Metabolism and Signaling in a Light-Damage Model of Age-Related Macular Degeneration

Resolvin E1 (RvE1) is an eicosapentaenoic acid-derived lipid mediator involved in the resolution of inflammation. Here, we investigated whether RvE1 alterations may occur in an animal model of age-related macular degeneration (AMD). To this end, Sprague Dawley albino rats underwent light damage (LD), and retinas and serum were analyzed immediately or seven days after treatment. Western blot of retinas showed that the RvE1 receptor ChemR23 and the RvE1 metabolic enzymes 5-LOX and COX-2 were unchanged immediately after LD, but they were significantly up-regulated seven days later. Instead, the RvE1 receptor BLT1 was not modulated by LD, and neither was the RvE1 degradative enzyme 15-PGDH. Moreover, ChemR23, 5-LOX, COX-2 and BLT1 were found to be more expressed in the inner retina under all experimental conditions, as observed through ImageJ plot profile analysis. Of note, amacrine cells highly expressed BLT1, while ChemR23 was highly expressed in the activated microglia of the outer retina. ELISA assays also showed that LD rats displayed significantly higher circulating levels and reduced retinal levels of RvE1 compared to controls. Altogether, our data indicate that RvE1 metabolism and signaling are modulated in the LD model, suggesting a potentially relevant role of this pathway in AMD.

Pneumonia-Induced Inflammation, Resolution and Cardiovascular Disease: Causes, Consequences and Clinical Opportunities

Pneumonia is inflammation in the lungs, which is usually caused by an infection. The symptoms of pneumonia can vary from mild to life-threatening, where severe illness is often observed in vulnerable populations like children, older adults, and those with preexisting health conditions. Vaccines have greatly reduced the burden of some of the most common causes of pneumonia, and the use of antimicrobials has greatly improved the survival to this infection. However, pneumonia survivors do not return to their preinfection health trajectories but instead experience an accelerated health decline with an increased risk of cardiovascular disease. The mechanisms of this association are not well understood, but a persistent dysregulated inflammatory response post-pneumonia appears to play a central role. It is proposed that the inflammatory response during pneumonia is left unregulated and exacerbates atherosclerotic vascular disease, which ultimately leads to adverse cardiac events such as myocardial infarction. For this reason, there is a need to better understand the inflammatory cross talk between the lungs and the heart during and after pneumonia to develop therapeutics that focus on preventing pneumonia-associated cardiovascular events. This review will provide an overview of the known mechanisms of inflammation triggered during pneumonia and their relevance to the increased cardiovascular risk that follows this infection. We will also discuss opportunities for new clinical approaches leveraging strategies to promote inflammatory resolution pathways as a novel therapeutic target to reduce the risk of cardiac events post-pneumonia.

Parasitic nematode secreted phospholipase A2 suppresses cellular and humoral immunity by targeting hemocytes in Drosophila melanogaster

A key aspect of parasitic nematode infection is the nematodes' ability to evade and/or suppress host immunity. This immunomodulatory ability is likely driven by the release of hundreds of excretory/secretory proteins (ESPs) during infection. While ESPs have been shown to display immunosuppressive effects on various hosts, our understanding of the molecular interactions between individual proteins released and host immunity requires further study. We have recently identified a secreted phospholipase A2 (sPLA2) released from the entomopathogenic nematode (EPN) Steinernema carpocapsae we have named Sc-sPLA2. We report that Sc-sPLA2 increased mortality of Drosophila melanogaster infected with Streptococcus pneumoniae and promoted increased bacterial growth. Furthermore, our data showed that Sc-sPLA2 was able to downregulate both Toll and Imd pathway-associated antimicrobial peptides (AMPs) including drosomycin and defensin, in addition to suppressing phagocytosis in the hemolymph. Sc-sPLA2 was also found to be toxic to D. melanogaster with the severity being both dose- and time-dependent. Collectively, our data highlighted that Sc-sPLA2 possessed both toxic and immunosuppressive capabilities.

Aspirin-Triggered Resolvin D1 (AT-RvD1) Protects Mouse Skin against UVB-Induced Inflammation and Oxidative Stress

Intense exposure to UVB radiation incites excessive production of reactive oxygen species (ROS) and inflammation. The resolution of inflammation is an active process orchestrated by a family of lipid molecules that includes AT-RvD1, a specialized proresolving lipid mediator (SPM). AT-RvD1 is derived from omega-3, which presents anti-inflammatory activity and reduces oxidative stress markers. The present work aims to investigate the protective effect of AT-RvD1 on UVB-induced inflammation and oxidative stress in hairless mice. Animals were first treated with 30, 100, and 300 pg/animal AT-RvD1 (i.v.) and then exposed to UVB (4.14 J/cm²). The results showed that 300 pg/animal of AT-RvD1 could restrict skin edema, neutrophil and mast cell infiltration, COX-2 mRNA expression, cytokine release, and MMP-9 activity and restore skin antioxidant capacity as per FRAP and ABTS assays and control O₂^•- production, lipoperoxidation, epidermal thickening, and sunburn cells development. AT-RvD1 could reverse the UVB-induced downregulation of Nrf2 and its downstream targets GSH, catalase, and NOQ-1. Our results suggest that by upregulating the Nrf2 pathway, AT-RvD1 promotes the expression of ARE genes, restoring the skin's natural antioxidant defense against UVB exposition to avoid oxidative stress, inflammation, and tissue damage.

Pro-inflammatory and pro-resolving lipid mediators of inflammation in HIV: effect of aspirin intervention

BACKGROUND

Persons with HIV (PWH) have an increased risk of cardiovascular disease (CVD) compared to HIV-seronegative individuals (SN). Inflammation contributes to this risk but the role of lipid mediators, with central roles in inflammation, in HIV infection remain to be established; further aspirin reduces CVD risk in the general population through production of some of these anti-inflammatory lipid mediators, but they have not been studied in PWH.

METHODS

We evaluated the relationship between plasma lipid mediators (i.e. 50 lipid mediators including classic eicosanoids and specialized pro-resolving mediators (SPMs)) and HIV status; and the impact of aspirin in PWH on regulating these autacoids. Plasma samples were obtained from 110 PWH receiving antiretroviral therapy (ART) from a randomized trial of aspirin (ACTG-A5331) and 107 matched SN samples (MACS-WIHS Combined Cohort).

FINDINGS

PWH had lower levels of arachidonic acid-derived pro-inflammatory prostaglandins (PGs: PGE2 and PGD2) and thromboxanes (Tx: TxB2), and higher levels of select pro-resolving lipid mediators (e.g. RvD4 and MaR2n-3 DPA) compared to SN. At the interval tested, aspirin intervention was observed to reduced PGs and Tx, and while we did not observe an increase in aspirin triggered mediators, we observed the upregulation of other SPM in aspirin treated PWH, namely MaR2n-3 DPA.

INTERPRETATION

Together these observations demonstrate that plasma lipid mediators profiles, some with links to systemic inflammation and CVD risk, become altered in PWH. Furthermore, aspirin intervention did not increase levels of aspirin-triggered pro-resolving lipid mediators, consistent with other reports of an impaired aspirin response in PWH.

FUNDING

NIH.

An update on animal models of intervertebral disc degeneration and low back pain: Exploring the potential of artificial intelligence to improve research analysis and development of prospective therapeutics

Animal models have been invaluable in the identification of molecular events occurring in and contributing to intervertebral disc (IVD) degeneration and important therapeutic targets have been identified. Some outstanding animal models (murine, ovine, chondrodystrophoid canine) have been identified with their own strengths and weaknesses. The llama/alpaca, horse and kangaroo have emerged as new large species for IVD studies, and only time will tell if they will surpass the utility of existing models. The complexity of IVD degeneration poses difficulties in the selection of the most appropriate molecular target of many potential candidates, to focus on in the formulation of strategies to effect disc repair and regeneration. It may well be that many therapeutic objectives should be targeted simultaneously to effect a favorable outcome in human IVD degeneration. Use of animal models in isolation will not allow resolution of this complex issue and a paradigm shift and adoption of new methodologies is required to provide the next step forward in the determination of an effective repairative strategy for the IVD. AI has improved the accuracy and assessment of spinal imaging supporting clinical diagnostics and research efforts to better understand IVD degeneration and its treatment. Implementation of AI in the evaluation of histology data has improved the usefulness of a popular murine IVD model and could also be used in an ovine histopathological grading scheme that has been used to quantify degenerative IVD changes and stem cell mediated regeneration. These models are also attractive candidates for the evaluation of novel anti-oxidant compounds that counter inflammatory conditions in degenerate IVDs and promote IVD regeneration. Some of these compounds also have pain-relieving properties. AI has facilitated development of facial recognition pain assessment in animal IVD models offering the possibility of correlating the potential pain alleviating properties of some of these compounds with IVD regeneration.

Pain-resolving immune mechanisms in neuropathic pain

Interactions between the immune and nervous systems are of central importance in neuropathic pain, a common and debilitating form of chronic pain caused by a lesion or disease affecting the somatosensory system. Our understanding of neuroimmune interactions in pain research has advanced considerably. Initially considered as passive bystanders, then as culprits in the pathogenesis of neuropathic pain, immune responses in the nervous system are now established to underpin not only the initiation and progression of pain but also its resolution. Indeed, immune cells and their mediators are well-established promoters of neuroinflammation at each level of the neural pain pathway that contributes to pain hypersensitivity. However, emerging evidence indicates that specific subtypes of immune cells (including antinociceptive macrophages, pain-resolving microglia and T regulatory cells) as well as immunoresolvent molecules and modulators of the gut microbiota-immune system axis can reduce the pain experience and contribute to the resolution of neuropathic pain. This Review provides an overview of the immune mechanisms responsible for the resolution of neuropathic pain, including those involved in innate, adaptive and meningeal immunity as well as interactions with the gut microbiome. Specialized pro-resolving mediators and therapeutic approaches that target these neuroimmune mechanisms are also discussed.

Mast cells contribute to the resolution of allergic inflammation by releasing resolvin D1

BACKGROUND

Mast cells are initiators and main effectors of allergic inflammation, together with eosinophils, with whom they can interact in a physical and soluble cross-talk with marked pro-inflammatory features, the Allergic Effector Unit. The pro-resolution role of mast cells, alone or in co-culture with eosinophils, has not been characterized yet.

OBJECTIVES

We aimed to investigate select pro-resolution pathways in mast cells in vitro and in vivo in allergic inflammation.

METHODS

In vitro, we employed human and murine mast cells and analyzed release of resolvin D1 and expression of 15-lipoxygenase after IgE-mediated activation. We performed co-culture of IgE-activated mast cells with peripheral blood eosinophils and investigated 15-lipoxygenase expression and Resolvin D1 release. In vivo, we performed Ovalbumin/Alum and Ovalbumin/S. aureus enterotoxin B allergic peritonitis model in Wild Type mice following a MC "overshoot" protocol.

RESULTS

We found that IgE-activated mast cells release significant amounts of resolvin D1 30 min after activation, while 15-lipoxygenase expression remained unchanged. Resolvin D1 release was found to be decreased in IgE-activated mast cells co-cultured with peripheral blood eosinophils for 30 min In vivo, mast cell-overshoot mice exhibited a trend of reduced inflammation, together with increased peritoneal resolvin D1 release.

CONCLUSIONS

Mast cells can actively contribute to resolution of allergic inflammation by releasing resolvin D1.

Targeting Angiogenesis via Resolution of Inflammation

Angiogenesis, the growth of new blood vessels, plays a critical role in tissue repair and regeneration, as well as in cancer. A paradigm shift is emerging in our understanding of the resolution of inflammation as an active biochemical process with the discovery of novel endogenous specialized pro-resolving mediators (SPMs), including resolvins. Angiogenesis and the resolution of inflammation are critical interdependent processes. Disrupted inflammation resolution can accelerate tumor growth, which is angiogenesis-dependent. SPMs, including resolvins and lipoxins, inhibit physiologic and pathological angiogenesis at nanogram concentrations. The failure of resolution of inflammation is an emerging hallmark of angiogenesis-dependent diseases including arthritis, psoriasis, diabetic retinopathy, age-related macular degeneration, inflammatory bowel disease, atherosclerosis, endometriosis, Alzheimer's disease, and cancer. Whereas therapeutic angiogenesis repairs tissue damage (e.g., limb ischemia), inhibition of pathological angiogenesis suppresses tumor growth and other non-neoplastic diseases such as retinopathies. Stimulation of resolution of inflammation via pro-resolving lipid mediators promotes the repair of tissue damage and wound healing, accelerates tissue regeneration, and inhibits cancer. Here we provide an overview of the mechanisms of cross talk between angiogenesis and inflammation resolution in chronic inflammation-driven diseases. Stimulating the resolution of inflammation via pro-resolving lipid mediators has emerged as a promising new field to treat angiogenic diseases.

Possibility of averting cytokine storm in SARS-COV 2 patients using specialized pro-resolving lipid mediators

Fatal "cytokine storms (CS)" observed in critically ill COVID-19 patients are consequences of dysregulated host immune system and over-exuberant inflammatory response. Acute respiratory distress syndrome (ARDS), multi-system organ failure, and eventual death are distinctive symptoms, attributed to higher morbidity and mortality rates among these patients. Consequent efforts to save critical COVID-19 patients via the usage of several novel therapeutic options are put in force. Strategically, drugs being used in such patients are dexamethasone, remdesivir, hydroxychloroquine, etc. along with the approved vaccines. Moreover, it is certain that activation of the resolution process is important for the prevention of chronic diseases. Until recently Inflammation resolution was considered a passive process, rather it's an active biochemical process that can be achieved by the use of specialized pro-resolving mediators (SPMs). These endogenous mediators are an array of atypical lipid metabolites that include Resolvins, lipoxins, maresins, protectins, considered as immunoresolvents, but their role in COVID-19 is ambiguous. Recent evidence from studies such as the randomized clinical trial, in which omega 3 fatty acid was used as supplement to resolve inflammation in COVID-19, suggests that direct supplementation of SPMs or the use of synthetic SPM mimetics (which are still being explored) could enhance the process of resolution by regulating the aberrant inflammatory process and can be useful in pain relief and tissue remodeling. Here we discussed the biosynthesis of SPMs, & their mechanistic pathways contributing to inflammation resolution along with sequence of events leading to CS in COVID-19, with a focus on therapeutic potential of SPMs.

The role of non-steroidal anti-inflammatory drugs as adjuncts to periodontal treatment and in periodontal regeneration

Periodontitis is the sixth most prevalent chronic disease globally and places significant burdens on societies and economies worldwide. Behavioral modification, risk factor control, coupled with cause-related therapy have been the "gold standard" treatment for managing periodontitis. Given that host inflammatory and immunological responses play critical roles in the pathogenesis of periodontitis and impact treatment responses, several adjunctive strategies aimed at modulating host responses and improving the results of periodontal therapy and maintenance have been proposed. Of the many pharmacological host modulators, we focused on non-steroidal anti-inflammatory drugs (NSAIDs), due to their long history and extensive use in relieving inflammation and pain and reducing platelet aggregation. NSAIDs have been routinely indicated for treating rheumatic fever and osteoarthritis and utilized for the prevention of cardiovascular events. Although several efforts have been made to incorporate NSAIDs into the treatment of periodontitis, their effects on periodontal health remain poorly characterized, and concerns over the risk-benefit ratio were also raised. Moreover, there is emerging evidence highlighting the potential of NSAIDs, especially aspirin, for use in periodontal regeneration. This review summarizes and discusses the use of NSAIDs in various aspects of periodontal therapy and regeneration, demonstrating that the benefits of NSAIDs as adjuncts to conventional periodontal therapy remain controversial. More recent evidence suggests a promising role for NSAIDs in periodontal tissue engineering and regeneration.

Stereocontrolled total synthesis of Resolvin D4 and 17(R)-Resolvin D4

The total synthesis of Resolvin D4 and its 17(R)-hydroxy-epimer is reported. These lipid-based natural products are biosynthesized from docosahexaenoic acid (DHA, C22:6) during the body's rapid cellular and chemical response to injurious stimuli and are part of a large class of bioactive molecules that resolve inflammation. Our convergent synthesis employed a chiral pool strategy starting from glycidol derivatives and D-erythrose to introduce stereogenic centers. A copper(I)-mediated cross coupling between propargyl bromide and terminal acetylenic precursors yielded core structures of late-stage key intermediates. A simultaneous Lindlar reduction of the skipped diynyl moiety followed by silyl group cleavage securely completed the synthesis. The synthetic availability of these molecules helped further elucidate their stereoselective biofunctions.

Formyl peptide receptor 2 is an emerging modulator of inflammation in the liver

Formyl peptide receptors (FPRs), which are seven-membrane G-protein coupled receptors, recognize chemotactic signals to protect hosts from pathogenic infections and mediate inflammatory responses in the body. There are three isoforms of FPRs in humans-FPR1, FPR2, and FPR3-and they bind to N-formyl peptides, except FPR3, and to various endogenous agonists. Among FPR family members, FPR2 has a lower affinity for N-formyl peptides than FPR1 and binds with a wide range of endogenous or exogenous agonists. Thus, FPR2 is considered the most ambiguous member. Accumulating evidence has shown that FPR2 is involved in the host's defense against bacterial infection and inflammation in liver diseases, such as nonalcoholic fatty liver disease, liver fibrosis, and liver cancer, suggesting the pathophysiological relevance of FPR2 to the liver. However, FPR2 has been shown to promote or suppress inflammation, depending on the type of FPR2-expressing cell and FPR2-bound ligands in the liver. Therefore, it is important to understand FPR2's function per se and to elucidate the mechanism underlying immunomodulation initiated by ligand-activated FPR2 before suggesting FPR2 as a novel therapeutic agent for liver diseases. In this review, up-to-date knowledge of FPR2, with general information on the FPR family, is provided. We shed light on the dual action of FPR2 in the liver and discuss the hepatoprotective roles of FPR2 itself and FPR2 agonists in mediating anti-inflammatory responses.

Omega-3 polyunsaturated fatty acids inhibit cardiomyocyte apoptosis and attenuate sepsis-induced cardiomyopathy

OBJECTIVES

Sepsis can cause myocardial injury, which is one of the leading causes of death in critically ill patients. Fish oil rich in omega-3 polyunsaturated fatty acids (PUFAs) in ultralong chains has immunomodulatory effects and can inhibit the production of various critically ill proinflammatory cytokines. Therefore, this study focused on whether ω-3 PUFAs have a protective effect on sepsis-induced cardiomyopathy (SIC).

METHODS

Male 6-8 weeks old C57BL/6 mice were pretreated with 3% special fish oil supplement rat food for seven consecutive days prior to surgery. Cecal ligation and puncture (CLP) was perfromed to induce polymicrobial sepsis.The cardiac function was assessed by echocardiography, apoptosis of cardiomyocyte were detected by TUNEL assay and Western blotting, and the level of TNF-α, IL-6, and IL-1β in plasma was determined 24h after CLP.

RESULTS

Pretreatment with omega-3 PUFAs attenuated cardiomyocyte apoptosis, decreased the production of proinflammatory cytokines, attenuated the SIC, and improved the survival rate of septic mice induced by CLP.

CONCLUSIONS

ω-3 PUFAs alleviate SIC through attenuating cardiomyocyte apoptosis, which provides a new direction for the prevention and treatment of SIC.

Resolution Pharmacology: Focus on Pro-Resolving Annexin A1 and Lipid Mediators for Therapeutic Innovation in Inflammation

Chronic diseases that affect our society are made more complex by comorbidities and are poorly managed by the current pharmacology. While all present inflammatory etiopathogeneses, there is an unmet need for better clinical management of these diseases and their multiple symptoms. We discuss here an innovative approach based on the biology of the resolution of inflammation. Studying endogenous pro-resolving peptide and lipid mediators, how they are formed, and which target they interact with, can offer innovative options through augmenting the expression or function of pro-resolving pathways or mimicking their actions with novel targeted molecules. In all cases, resolution offers innovation for the treatment of the primary cause of a given disease and/or for the management of its comorbidities, ultimately improving patient quality of life. By implementing resolution pharmacology, we harness the whole physiology of inflammation, with the potential to bring a marked change in the management of inflammatory conditions.

The hypoxic tissue microenvironment as a driver of mucosal inflammatory resolution

On the backdrop of all acute inflammatory processes lies the activation of the resolution response. Recent years have witnessed an emerging interest in defining molecular factors that influence the resolution of inflammation. A keystone feature of the mucosal inflammatory microenvironment is hypoxia. The gastrointestinal tract, particularly the colon, exists in a state of physiological hypoxia and during active inflammation, this hypoxic state is enhanced as a result of infiltrating leukocyte oxygen consumption and the activation of oxygen consuming enzymes. Most evidence suggests that mucosal hypoxia promotes the active resolution of inflammation through a variety of mechanisms, including extracellular acidification, purine biosynthesis/salvage, the generation of specialized pro-resolving lipid mediators (ie. resolvins) and altered chemokine/cytokine expression. It is now appreciated that infiltrating innate immune cells (neutrophils, eosinophils, macrophages) have an important role in molding the tissue microenvironment to program an active resolution response. Structural or functional dysregulation of this inflammatory microenvironment can result in the loss of tissue homeostasis and ultimately progression toward chronicity. In this review, we will discuss how inflammatory hypoxia drives mucosal inflammatory resolution and its impact on other microenvironmental factors that influence resolution.

Current experimental methods to investigate the impact of specialized pro-resolving lipid mediators on Sjögren's syndrome

Sjögren's syndrome is a chronic inflammatory autoimmune disease characterized by diminished secretory function of the exocrine glands. Although extensive investigation has been done to understand Sjögren's syndrome, the causes of the disease are as yet unknown and treatments remain largely ineffective, with established therapeutic interventions being limited to use of saliva substitutes with modest effectiveness. A primary feature of Sjögren's syndrome is uncontrolled inflammation of exocrine tissues and previous studies have demonstrated that lipid-based specialized pro-resolving mediators reduce inflammation and restores tissue integrity in salivary glands. However, these studies are limited to a single specialized pro-resolving lipid mediator's family member resolvin D1 or RvD1 and its aspirin-triggered epimer, AT-RvD1. Consequently, additional studies are needed to explore the potential benefits of other members of the specialized pro-resolving lipid mediator's family and related molecules (e.g., additional resolvin subtypes as well as lipoxins, maresins and protectins). In support of this goal, the current review aims to briefly describe the range of current experimental methods to investigate the impact of specialized pro-resolving lipid mediators on Sjögren's syndrome, including both strengths and weaknesses of each approach where this information is known. With this article, the possibilities presented by specialized pro-resolving lipid mediators will be introduced to a wider audience in immunology and practical advice is given to researchers who may wish to take up this work.

Omega-3 polyunsaturated fatty acids and corneal nerve health: Current evidence and future directions

Corneal nerves play a key role in maintaining ocular surface integrity. Corneal nerve damage, from local or systemic conditions, can lead to ocular discomfort, pain, and, if poorly managed, neurotrophic keratopathy. Omega-3 polyunsaturated fatty acids (PUFAs) are essential dietary components that play a key role in neural development, maintenance, and function. Their potential application in modulating ocular and systemic inflammation has been widely reported. Omega-3 PUFAs and their metabolites also have neuroprotective properties and can confer benefit in neurodegenerative disease. Several preclinical studies have shown that topical administration of omega-3 PUFA-derived lipid mediators promote corneal nerve recovery following corneal surgery. Dietary omega-3 PUFA supplementation can also reduce corneal epithelial nerve loss and promote corneal nerve regeneration in diabetes. Omega-3 PUFAs and their lipid mediators thus show promise as therapeutic approaches to modulate corneal nerve health in ocular and systemic disease. This review discusses the role of dietary omega-3 PUFAs in maintaining ocular surface health and summarizes the possible applications of omega-3 PUFAs in the management of ocular and systemic conditions that cause corneal nerve damage. In examining the current evidence, this review also highlights relatively underexplored applications of omega-3 PUFAs in conferring neuroprotection and addresses their therapeutic potential in mediating corneal nerve regeneration.

Hydrolysis of polyhydroxy polyunsaturated fatty acid-glycerophosphocholines by Group IIA, V, and X secretory phospholipases A2

It is widely accepted that unesterified polyunsaturated ω-6 and ω-3 fatty acids (PUFA) are converted through various lipoxygenases, cyclooxygenases, and cytochrome P450 enzymes to a range of oxygenated derivatives (oxylipins), among which the polyhydroxides of unesterified PUFA have recently been recognized as cell signaling molecules with anti-inflammatory and pro-resolving properties, known as specialized pro-resolving mediators (SPMs). This study investigates the mono-, di-, and trihydroxy 16:0/PUFA-GPCs, and the corresponding 16:0/SPM-GPC, in plasma lipoproteins. We describe the isolation and identification of mono-, di-, and trihydroxy AA, EPA, and DHA-GPC in plasma LDL, HDL, HDL3, and acute phase HDL using normal phase LC/ESI-MS, as previously reported. The lipoproteins contained variable amounts of the polyhydroxy-PUFA-GPC (0-10 nmol/mg protein), likely the product of lipid peroxidation and the action of various lipoxygenases and cytochrome P450 enzymes on both free fatty acids and the parent GPCs. Polyhydroxy-PUFA-GPC was hydrolyzed to variable extent (20%-80%) by the different secretory phospholipases A₂ (sPLA₂ s), with Group IIA sPLA₂ showing the lowest and Group X sPLA₂ the highest activity. Surprisingly, the trihydroxy-16:0/PUFA-GPC of APHDL was largely absent, while large amounts of unidentified material had migrated in the free fatty acid elution area. The free fatty acid mass spectra were consistent with that anticipated for branched chain polyhydroxy fatty acids. There was general agreement between the masses determined by LC/ESI-MS for the polyhydroxy PUFA-GPC and the masses calculated for the GPC equivalents of resolvins, protectins, and maresins using the fatty acid structures reported in the literature.

Anti-Inflammatory Effect of Specialized Proresolving Lipid Mediators on Mesenchymal Stem Cells: An In Vitro Study

An interconnection between tissue inflammation and regeneration has been established through the regulation of defense and repair mechanisms within diseased dental tissue triggered by the release of immune-resolvent mediators. To better our understanding of the role of specific pro-resolving mediators (SPMs) in inflamed human bone marrow-derived mesenchymal stem cells (hBMMSCs), we studied the effects of Resolvin E1 (RvE1) and Maresin 1 (MaR1) in lipopoly-saccharide (LPS) stimulated hBMMSCs. The hBMMSCs were divided into five different groups, each of which was treated with or without SPMs. Group-1: negative control (no LPS stimulation), Group-2: positive control (LPS-stimulated), Group-3: RvE1 100 nM + 1 μg/mL LPS, Group-4: MaR1 100 nM + 1 µg/mL LPS, and Group-5: RvE1 100 nM + MaR1100 nM + 1 μg/mL LPS. Cell proliferation, apoptosis, migration, colony formation, Western blotting, cytokine array, and LC/MS analysis were all performed on each group to determine the impact of SPMs on inflammatory stem cells. According to our data, RvE1 plus MaR1 effectively reduced inflammation in hBMMSCs. In particular, IL-4, 1L-10, and TGF-β1 activation and downregulation of RANKL, TNF-α, and IFN-γ compared to groups receiving single SPM were shown to be significantly different (Group 3 and 4). In addition, the LC/MS analysis revealed the differentially regulated peptide's role in immunological pathways that define the cellular state against inflammation. Inflamed hBMMSCs treated with a combination of Resolvin E1 (RvE1) and Maresin 1 (MaR1) promoted the highest inflammatory resolution compared to the other groups; this finding suggests a potential new approach of treating bacterially induced dental infections.

Sex Dimorphism in Resolvin D5-induced Analgesia in Rat Models of Trigeminal Pain

Resolvin D5 (RvD5) is a specialized pro-resolving lipid mediator with potent anti-inflammatory and analgesic properties. Orofacial pain conditions, especially those that are chronic, present clinical challenges in terms of pharmacological management. Thus, new therapeutic options are clearly warranted. Herein, we investigated the antinociceptive effect of RvD5 in the chronic constriction injury of the infraorbital nerve (CCI-ION) model and in the orofacial formalin test in female and male Wistar rats. Our results indicated that repeated subarachnoid medullary injections of RvD5 at 10 ng resulted in a significant reduction of heat and mechanical hyperalgesia induced by the CCI-ION in male and female rats, but males were more sensitive to RvD5 effects. In addition, after CCI-ION, interleukin-6 (IL-6) level was increased in the trigeminal nucleus caudalis of male, but not female rats, which was reduced by RvD5 repeated treatment. No changes in the levels of IL-1β were found. Minocycline blocked the effect of RvD5 in male rats but failed to affect RvD5 antinociceptive effect in females. Moreover, a single medullary injection of RvD5 caused a significant reduction of formalin-induced facial grooming, in phases I and II of the test, but only in male rats. This study demonstrated for the first time the analgesic effect of RvD5 in trigeminal pain models, and corroborated previous evidence of sex dichotomy, with a greater effect in males. This article presents a translational potential of RvD5 for targeted therapies aiming at the control of acute and chronic trigeminal pain, but further studies are needed to elucidate its sex-related mechanisms. PERSPECTIVE: This study demonstrated that RvD5 may provide the benefits for trigeminal neuropathic pain treatment in male and female rats, but its effect on inflammatory orofacial pain seems to be restricted only to males. Also, it provided the evidence for sex dichotomy in the mechanisms related to the antinociceptive effect of RvD5.

Resolution of post-lung transplant ischemia-reperfusion injury is modulated via Resolvin D1-FPR2 and Maresin 1-LGR6 signaling

BACKGROUND

Dysregulation of inflammation-resolution pathways leads to postlung transplant (LTx) ischemia-reperfusion (IR) injury and allograft dysfunction. Our hypothesis is that combined treatment with specialized pro-resolving lipid mediators, that is, Resolvin D1 (RvD1) and Maresin-1 (MaR1), enhances inflammation-resolution of lung IR injury.

METHODS

Expression of RvD1 and MaR1 was analyzed in bronchoalveolar lavage (BAL) fluid of patients on days 0, 1, and 7 post-LTx. Lung IR injury was evaluated in C57BL/6 (WT), FPR2^-/-, and LGR6 siRNA treated mice using a hilar-ligation model with or without administration with RvD1 and/or MaR1. A donation after circulatory death and murine orthotopic lung transplantation model was used to evaluate the protection by RvD1 and MaR1 against lung IR injury. In vitro studies analyzed alveolar macrophages and type II epithelial cell activation after treatment with RvD1 or MaR1.

RESULTS

RvD1 and MaR1 expressions in BAL from post-LTx patients was significantly increased on day 7 compared to days 0 and 1. Concomitant RvD1 and MaR1 treatment significantly mitigated early pulmonary inflammation and lung IR injury in WT mice, which was regulated via FPR2 and LGR6 receptors. In the murine orthotopic donation after cardiac death LTx model, RvD1 and MaR1 treatments significantly attenuated lung IR injury and increased PaO₂ levels compared to saline-treated controls. Mechanistically, RvD1/FPR2 signaling on alveolar macrophages attenuated HMGB1 and TNF-α secretion and upregulated uptake of macrophage-dependent apoptotic neutrophils (efferocytosis), whereas MaR1/LGR6 signaling mitigated CXCL1 secretion by epithelial cells.

CONCLUSIONS

Bioactive proresolving lipid mediator-dependent signaling that is, RvD1/FPR2 and MaR1/LGR6- offers a novel therapeutic strategy in post-LTx injury.

Protectins: Their biosynthesis, metabolism and structure-functions

Several lipoxygenase enzymes and cyclooxygenase-2 stereoselectively convert the polyunsaturated fatty acids arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and n-3 docosapentaenoic acid into numerous oxygenated products. Biosynthetic pathway studies have shown, during the resolution phase of acute inflammation, that distinct families of endogenous products are formed. These products were named specialized pro-resolving mediators, given their specialized functions in the inflammation-resolution circuit, enhancing the return of inflamed and injured tissue to homeostasis. The lipoxins, resolvins, protectins and maresins, together with the sulfido-conjugates of the resolvins, protectins and maresins, constitute the four individual families of these local mediators. When administrated in vivo in a wide range of human disease models, the specialized pro-resolving mediators display potent bioactions. The detailed and individual biosynthetic steps constituting the biochemical pathways, the metabolism, recent reports on structure-function studies and pharmacodynamic data of the protectins, are presented herein. Emphasis is on the structure-function results on the recent members of the sulfido conjugated protectins and further metabolism of protectin D1. Moreover, the members of the individual families of specialized pro-resolving mediators and their biosynthetic precursor are presented. Today 43 specialized pro-resolving mediators possessing pro-resolution and anti-inflammatory bioactions are reported and confirmed, constituting a basis for resolution pharmacology. This emerging biomedical field provides a new approach for drug discovery, that is also discussed.

Major structure-activity relationships of resolvins, protectins, maresins and their analogues

Resolvins, protectins and maresins are a series of polyunsaturated fatty acid-derived molecules which play important roles in the resolution of inflammation. They are termed specialized proresolving mediators and facilitate a return to homeostasis following an inflammatory response. These molecules are currently the focus of intensive investigation, primarily for their ability to suppress inflammation in chronic disease states. Researchers have employed different synthetic approaches to assess whether various structural modifications of these compounds could provide access to future therapeutics. This review summarizes the modifications made thus far and focuses on the key structure-activity relationships which have been uncovered for resolvins, protectins, maresins and their analogues.

Reevaluation of a Bicyclic Pyrazoline as a Selective 15-Lipoxygenase V-Type Activator Possessing Fatty Acid Specificity

Regulation of lipoxygenase (LOX) activity is of great interest due to the involvement of the various LOX isoforms in the inflammatory process and hence many diseases. The bulk of investigations have centered around the discovery and design of inhibitors. However, the emerging understanding of the role of h15-LOX-1 in the resolution of inflammation provides a rationale for the development of activators as well. Bicyclic pyrazolines are known bioactive molecules that have been shown to display antibiotic and anti-inflammatory activities. In the current work, we reevaluated a previously discovered bicyclic pyrazoline h15-LOX-1 activator, PKUMDL_MH_1001 (written as 1 for this publication), and determined that it is inactive against other human LOX isozymes, h5-LOX, h12-LOX, and h15-LOX-2. Analytical characterization of 1 obtained in the final synthesis step identified it as a mixture of cis- and trans-diastereomers: cis-1 (12%) and trans-1 (88%); and kinetic analysis indicated similar potency between the two. Using compound 1 as the cis-trans mixture, h15-LOX-1 catalysis with arachidonic acid (AA) (AC50 = 7.8 +/- 1 μM, A max = 240%) and linoleic acid (AC50 = 5.3 +/- 0.7 μM, A max = 98%) was activated, but not with docosahexaenoic acid (DHA) or mono-oxylipins. Steady-state kinetics demonstrate V-type activation for 1, with a β value of 2.2 +/- 0.4 and an K x of 16 +/- 1 μM. Finally, it is demonstrated that the mechanism of activation for 1 is likely not due to decreasing substrate inhibition, as was postulated previously. 1 also did not affect the activity of the h15-LOX-1 selective inhibitor, ML351, nor did 1 affect the activity of allosteric effectors, such as 12S-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12S-HETE) and 14S-hydroperoxy-4Z,7Z,10Z,12E,16Z,19Z-docosahexaenoic acid (14S-HpDHA). These data confirm that 1 binds to a distinct activation binding site, as previously postulated. Future work should be aimed at the development of selective activators that are capable of activating h15-LOX-1 catalysis with DHA, thus enhancing the production of DHA-derived pro-resolution biomolecules.

Omega-3 pleiad: The multipoint anti-inflammatory strategy

Omega 3 (ω3) fatty acids have been described since the 1980s as promising anti-inflammatory substances. Prostaglandin and leukotriene modulation were exhaustively explored as the main reason for ω3 beneficial outcomes. However, during the early 2000s, after the human genome decoding advent, the nutrigenomic approaches exhibited an impressive plethora of ω3 targets, now under the molecular point of view. Different G protein-coupled receptors (GPCRs) recognizing ω3 and its derivatives appear to be responsible for blocking inflammation and insulin-sensitizing effects. A new class of ω3-derived substances, such as maresins, resolvins, and protectins, increases ω3 actions. Inflammasome disruption, the presence of GPR120 on immune cell surfaces, and intracellular crosstalk signaling mediated by PPARγ compose the last discoveries regarding the multipoint anti-inflammatory targets for this nutrient. This review shows a detailed mechanistic proposal to understand ω3 fatty acid action over the inflammatory environment in the background of several chronic diseases.

Arachidonate 15-lipoxygenase type B: Regulation, function, and its role in pathophysiology

As a lipoxygenase (LOX), arachidonate 15-lipoxygenase type B (ALOX15B) peroxidizes polyenoic fatty acids (PUFAs) including arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid (LA) to their corresponding fatty acid hydroperoxides. Distinctive to ALOX15B, fatty acid oxygenation occurs with positional specificity, catalyzed by the non-heme iron containing active site, and in addition to free PUFAs, membrane-esterified fatty acids serve as substrates for ALOX15B. Like other LOX enzymes, ALOX15B is linked to the formation of specialized pro-resolving lipid mediators (SPMs), and altered expression is apparent in various inflammatory diseases such as asthma, psoriasis, and atherosclerosis. In primary human macrophages, ALOX15B expression is associated with cellular cholesterol homeostasis and is induced by hypoxia. Like in inflammation, the role of ALOX15B in cancer is inconclusive. In prostate and breast carcinomas, ALOX15B is attributed a tumor-suppressive role, whereas in colorectal cancer, ALOX15B expression is associated with a poorer prognosis. As the biological function of ALOX15B remains an open question, this review aims to provide a comprehensive overview of the current state of research related to ALOX15B.

Clinical significance of polyunsaturated fatty acids in the prevention of cardiovascular diseases

Cardiovascular diseases are one of the most important problems of modern medicine. They are associated with a large number of health care visits, hospitalizations and mortality. Prevention of atherosclerosis is one of the most effective strategies and should start as early as possible. Correction of lipid metabolism disorders is associated with definite clinical successes, both in primary prevention and in the prevention of complications of many cardiovascular diseases. A growing body of evidence suggests a multifaceted role for polyunsaturated fatty acids. They demonstrate a variety of functions in inflammation, both participating directly in a number of cellular processes and acting as a precursor for subsequent biosynthesis of lipid mediators. Extensive clinical data also support the importance of polyunsaturated fatty acids, but all questions have not been answered to date, indicating the need for further research.

Resolvin E1 Reduces Tumor Growth in a Xenograft Model of Lung Cancer

Inflammation plays a significant role in carcinogenesis and tumor growth. The current study was designed to test the hypothesis that resolvin E1 (RvE1) and overexpression of the receptor for RvE1 (ERV1) will prevent and/or reverse tumor generation in a gain-of-function mouse model of tumor seeding with lung cancer cells. To measure the impact of enhanced resolution of inflammation on cancer pathogenesis, ERV1-overexpressing transgenic (TG) and wild-type FVB mice were given an injection of 1 × 106 LA-P0297 cells subcutaneously and were treated with RvE1 (100 ng; intraperitoneally) or placebo. To assess the impact of RvE1 as an adjunct to chemotherapy, ERV1-TG and wild-type FVB mice were treated with cisplatin or cisplatin + RvE1. RvE1 significantly prevented tumor growth and reduced tumor size, cyclooxygenase-2, NF-κB, and proinflammatory cytokines in TG animals as compared to wild-type animals. A significant decrease in Ki-67, vascular endothelial growth factor, angiopoietin (Ang)-1, and Ang-2 was also observed in TG animals as compared to wild-type animals. Tumor-associated neutrophils and macrophages were significantly reduced by RvE1 in transgenics (P < 0.001). RvE1 administration with cisplatin led to a significant reduction of tumor volume and reduced cyclooxygenase-2, NF-κB, vascular endothelial growth factor-A, Ang-1, and Ang-2. These data suggest that RvE1 prevents inflammation and vascularization, reduces tumor seeding and tumor size, and, when used as an adjunct to chemotherapy, enhances tumor reduction at significantly lower doses of cisplatin.

Impact of health and lifestyle food supplements on periodontal tissues and health

According to the new classification, periodontitis is defined as a chronic multifactorial inflammatory disease associated with dysbiotic biofilms and characterized by progressive destruction of the tooth-supporting apparatus. This definition, based on the current scientific evidence, clearly indicates and emphasizes, beside the microbial component dental biofilm, the importance of the inflammatory reaction in the progressive destruction of periodontal tissues. The idea to modulate this inflammatory reaction in order to decrease or even cease the progressive destruction was, therefore, a logical consequence. Attempts to achieve this goal involve various kinds of anti-inflammatory drugs or medications. However, there is also an increasing effort in using food supplements or so-called natural food ingredients to modulate patients' immune responses and maybe even improve the healing of periodontal tissues. The aim of this chapter of Periodontology 2000 is to review the evidence of various food supplements and ingredients regarding their possible effects on periodontal inflammation and wound healing. This review may help researchers and clinicians to evaluate the current evidence and to stimulate further research in this area.

Impact of preweaning vaccination on host gene expression and antibody titers in healthy beef calves

The impact of preweaning vaccination for bovine respiratory viruses on cattle health and subsequent bovine respiratory disease morbidity has been widely studied yet questions remain regarding the impact of these vaccines on host response and gene expression. Six randomly selected calves were vaccinated twice preweaning (T1 and T3) with a modified live vaccine for respiratory pathogens and 6 randomly selected calves were left unvaccinated. Whole blood samples were taken at first vaccination (T1), seven days later (T2), at revaccination and castration (T3), and at weaning (T4), and utilized for RNA isolation and sequencing. Serum from T3 and T4 was analyzed for antibodies to BRSV, BVDV1a, and BHV1. Sequenced RNA for all 48 samples was bioinformatically processed with a HISAT2/StringTie pipeline, utilizing reference guided assembly with the ARS-UCD1.2 bovine genome. Differentially expressed genes were identified through analyzing the impact of time across all calves, influence of vaccination across treatment groups at each timepoint, and the interaction of time and vaccination. Calves, regardless of vaccine administration, demonstrated an increase in gene expression over time related to specialized proresolving mediator production, lipid metabolism, and stimulation of immunoregulatory T-cells. Vaccination was associated with gene expression related to natural killer cell activity and helper T-cell differentiation, enriching for an upregulation in Th17-related gene expression, and downregulated genes involved in complement system activity and coagulation mechanisms. Type-1 interferon production was unaffected by the influence of vaccination nor time. To our knowledge, this is the first study to evaluate mechanisms of vaccination and development in healthy calves through RNA sequencing analysis.

Amelioration for oxidative stability and bioavailability of N-3 PUFA enriched microalgae oil: an overview

Technological improvements in dietary supplements and nutraceuticals have highlighted the significance of bioactive molecules in a healthy lifestyle. Eicosapentaenoic acid and Cervonic acid (DHA), omega-3 polyunsaturated fatty acids seem to be famed for their ability to prevent diverse physiological abnormalities. Selection of appropriate pretreatments and extraction techniques for extraction of lipids from robust microalgae cell wall are very important to retain their stability and bioactivity. Therefore, extraction techniques with optimized extraction parameters offer an excellent approach for obtaining quality oil with a high yield. Oils enriched in omega-3 are particularly imperiled to oxidation which ultimately affects customer acceptance. Bio active encapsulation could be one of the effective approaches to overcome this dilemma. This review paper aims to give insight into the cultivation methods, and downstream processes, various lipid extraction approaches, techniques for retaining oxidative stability, bioavailability and food applications based on extracted or encapsulated omega-3.

A newly synthesized 17-epi-NeuroProtectin D1/17-epi-Protectin D1: Authentication and functional regulation of Inflammation-Resolution

The production of specialized pro-resolving mediators (SPMs) during the resolution phase in the inflammatory milieu is key to orchestrating the resolution of the acute inflammatory response. 17-epi-neuroprotectin D1/17-epi-protectin D1 (17-epi-NPD1/17-epi-PD1: 10R,17R-dihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid) is an SPM of the protectin family, biosynthesized from docosahexaenoic acid (DHA), that exhibits both potent anti-inflammatory and neuroprotective functions. Here, we carried out a new commercial-scale synthesis of 17-epi-NPD1/17-epi-PD1 that enabled the authentication and confirmation of its potent bioactions in vivo and determination of its ability to activate human leukocyte phagocytosis. We provide evidence that this new synthetic 17-epi-NPD1/17-epi-PD1 statistically significantly increases human macrophage uptake of E. coli in vitro and confirm that it limits neutrophilic infiltration in vivo in a murine model of peritonitis. The physical properties of the new synthetic 17-epi-NPD1/17-epi-PD1, namely its ultra-violet absorbance, chromatography, and tandem mass spectrometry fragmentation pattern, matched those of the originally synthesized 17-epi-NPD1/17-epi-PD1. In addition, we verified the structure and complete stereochemical assignment of this new synthetic 17-epi-NPD1/17-epi-PD1 using nuclear magnetic resonance (NMR) spectroscopy. Together, these results authenticate this 17-epi-NPD1/17-epi-PD1 for its structure and potent pro-resolving functions.

Low dose aspirin associated with greater bone mineral density in older adults

The use of low-dose aspirin in older adults is increasing as is the prevalence of osteoporosis. Aspirin has been shown in numerous studies to affect bone metabolism. However, there is no clear link between low-dose aspirin use and bone mineral density (BMD). This study examined differences in bone mineral density between low-dose aspirin users and non-aspirin users in adults aged 50-80 years. We conducted a cross-sectional study of 15,560 participants who participated in the National Health and Nutrition Examination Survey (NHANES) 2017-March 2020. We used a multivariate logistic regression model to evaluate the relationship between low-dose aspirin and femoral neck BMD, femoral total BMD, intertrochanteric BMD, and the first lumbar vertebra BMD (L1 BMD) in patients aged 50 to 80 years. A total of 1208 (Group 1: femoral neck BMD, total femur BMD, and intertrochanter BMD) and 1228 (Group 2: L1 BMD) adults were included in this study. In both group 1 and group 2, BMD was higher in the low-dose aspirin group than in the non-aspirin group (Total femur BMD β = 0.019, 95% CI 0.004-0.034; Femoral neck BMD β = 0.017, 95% CI 0.002-0.032; Intertrochanter BMD β = 0.025, 95% CI 0.007-0.043; L1 BMD β = 0.026, 95% CI 0.006-0.046). In subgroup analyses stratified by gender, this positive association existed in both gender after adjusting for confounders. On subgroup analyses stratified by age, this positive association existed in three different age groups after adjusting for confounders. To test whether the effect of low-dose aspirin on BMD was affected by gender and age, the interaction P value was greater than 0.05. These findings from a human study looking into the relationship between low-dose aspirin use and BMD suggest that regular low-dose aspirin may be associated with a higher BMD. The association between low-dose aspirin and BMD did not differ by age group or gender.

A cell-free difunctional demineralized bone matrix scaffold enhances the recruitment and osteogenesis of mesenchymal stem cells by promoting inflammation resolution

The dialogue between host macrophages (Mφs) and endogenous mesenchymal stem cells (MSCs) promotes M2 Mφs polarization to resolve early-stage inflammation, thereby effectively guiding in situ bone regeneration. Once inflammation is unresolved/incontrollable, it will induce the impediment of MSCs homing at bone defect site, implying the seasonable resolution of inflammation in balancing bone homeostasis. Repeatedly, evidence elucidated that specialized pro-resolving mediators (SPMs) could conduce to proper resolve inflammation and promote the repairing of bone defect. A difunctional demineralized bone matrix (DBM) scaffold co-modified by maresin 1 (MaR1) and aptamer 19S (Apt19S) was fabricated to facilitate the osteogenesis of MSCs. To confirm the osteogenesis and immunomodulatory role of the difunctional DBM scaffold, the proliferation, recruitment, and osteogenic differentiation of MSCs and the Mφs M2 subtype polarization were evaluated in vitro. Then, the DBM scaffolds were implanted into mice model with critical size calvarial defect to evaluate bone repair efficiency. Finally, the specific resolution mechanism in Mφs cultured on the difunctional DBM scaffold was further in-depth investigated. This difunctional DBM scaffold exhibited an enhanced function on the recruitment, proliferation, migration, osteogenesis of MSCs and the resolution of inflammation, finally improved bone-scaffold integration. At the same time, MaR1 modified on the difunctional DBM scaffold increased the biosynthesis of 12-lipoxygenase (12-LOX) and 12S-hydroxy-eicosatetraenoic acid (12S-HETE), and also directly stimulated lipid droplets (LDs) biogenesis in Mφs, which suggested that MaR1 regulated Mφ lipid metabolism at bone repair site. Findings based on this synergy strategy demonstrated that Mφ lipid metabolism was essential in bone homeostasis, which might provide a theoretical direction for the treatment-associated application of MaR1 in inflammatory bone disease.

Synergistic Neuroprotection by a PAF Antagonist Plus a Docosanoid in Experimental Ischemic Stroke: Dose-Response and Therapeutic Window

OBJECTIVE

We tested the hypothesis that blocking pro-inflammatory platelet-activating factor receptor (PAFR) with LAU-0901 (LAU) plus administering a selected docosanoid, aspirin-triggered neuroprotectin D1 (AT-NPD1), which activates cell-survival pathways after middle cerebral artery occlusion (MCAo), would lead to neurological recovery. Dose-response and therapeutic window were investigated.

MATERIALS AND METHODS

Male SD rats were subjected to 2 hours of MCAo. Behavior testing (days 1-7) and ex vivo MRI on day 7 were conducted. In dose-response, rats were treated with LAU (45 and 60 mg/kg; IP), AT-NPD1 (111, 222, 333 µg/kg; IV), LAU+AT-NPD1 (LAU at 3 hours and AT-NPD1 at 3.15 hours) or vehicle. In the therapeutic window, vehicle, LAU (60 mg/kg), AT-NPD1 (222 µg/kg), and LAU+AT-NPD1 were administered at 3, 4, 5, and 6 hours after onset of MCAo.

RESULTS

LAU and AT-NPD1 treatments alone improved behavior by 40-42% and 20-30%, respectively, and LAU+AT-NPD1 by 40% compared to the vehicle group. T2-weighted imaging (T2WI) volumes were reduced with all doses of LAU and AT-NPD1 by 73-90% and 67-83% and LAU+AT-NPD1 by 94% compared to vehicle. In the therapeutic window, LAU+AT-NPD1, when administered at 3, 4, 5, and 6 hours, improved behavior by 50, 56, 33, and 26% and reduced T2WI volumes by 93, 90, 82, and 84% compared to vehicle.

CONCLUSIONS

We have shown here for the first time that LAU plus AT-NPD1 treatment affords high-grade neuroprotection in MCAo, equaling or exceeding that afforded by LAU or AT-NPD1 alone at considerably moderate doses. It has a broad therapeutic window extending to 6 hours after stroke onset.

Patients with breath test positive are necessary to be identified from irritable bowel syndrome: a clinical trial based on microbiomics and rifaximin sensitivity

BACKGROUND

As a non-invasive and effective diagnostic method for small intestinal bacterial overgrowth (SIBO), wild-use of breath test (BT) has demonstrated a high comorbidity rate in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and SIBO. Patients overlapping with SIBO respond better to rifaximin therapy than those with IBS-D only. Gut microbiota plays a critical role in both of these two diseases. We aimed to determine the microbial difference between IBS-D overlapping with/without SIBO, and to study the underlying mechanism of its sensitivity to rifaximin.

METHODS

Patients with IBS-D were categorized as BT-negative (IBSN) and BT-positive (IBSP). Healthy volunteers (BT-negative) were enrolled as healthy control. The patients were clinically evaluated before and after rifaximin treatment (0.4 g bid, 4 weeks). Blood, intestine, and stool samples were collected for cytokine assessment and gut microbial analyses.

RESULTS

Clinical complaints and microbial abundance were significantly higher in IBSP than in IBSN. In contrast, severe systemic inflammation and more active bacterial invasion function that were associated with enrichment of opportunistic pathogens were seen in IBSN. The symptoms of IBSP patients were relieved in different degrees after therapy, but the symptoms of IBSN rarely changed. We also found that the presence of IBSN-enriched genera ( Enterobacter and Enterococcus ) are unaffected by rifaximin therapy.

CONCLUSIONS

IBS-D patients overlapping with SIBO showed noticeably different fecal microbial composition and function compared with IBS-D only. The better response to rifaximin in those comorbid patients might associate with their different gut microbiota, which suggests that BT is necessary before IBS-D diagnosis and use of rifaximin.

REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800017911.

Effects of adherence to the Mediterranean diet in children and adolescents with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder in children and adults, which increased over the past twenty years. The Mediterranean diet is a well-known diet full of antioxidants and anti-inflammatory ingredients.

AIM

To evaluate the safety, tolerability, and effects of adherence to the Mediterranean diet on disease patterns in children and adolescents with IBS.

METHODS

This prospective, cross-sectional case-controlled study included 100 consecutive IBS patients diagnosed according to Rome IV criteria, aged 12-18 years. Patients were subdivided into two groups (50 patients each); Group I received a Mediterranean diet, and Group II on their regular diet for six months. Besides IBS scores (IBS-SSS, IBS-QoL, and total score), different clinical and laboratory parameters were evaluated at the start and end of the study.

RESULTS

The Mediterranean diet was safe and well-tolerated in IBS patients. IBS children and adolescents with good adherence to the Mediterranean diet (KIDMED Score ≥ 8 points); group I showed significant improvement in IBS scores. IBS-SSS in the Mediterranean diet group was 237.2 ± 65 at the beginning of the study and decreased to 163.2 ± 33.8 at the end of the study (P < 0.001). It did not show a significant improvement in the group with a regular diet (248.3 ± 71.1 at the beginning of the study compared to 228.5 ± 54.3 at the study end with P < 0.05). The mean IBS-SSS in the Mediterranean diet group significantly improved compared with the group with a regular diet. Mean IBS-QoL in group I improved from 57.3 ± 12.9 at the start of the study to 72.4 ± 11.2 at the study end (P < 0.001) and significantly improved when compared to its level in group II at the study end (59.2 ± 12.7 with P < 0.001), while group II showed no significant improvement in IBS-QoL at the study end when compared to the beginning of the study (59.2 ± 11.7 with P >0.05). The mean total IBS score in group I became 28.8 ± 11.2 at the end of our study compared to 24.1 ± 10.4 at the start (P < 0.05) and significantly improved when compared to its level in group II at the end of the study (22.1 ± 12.5 with P < 0.05), while in group II, non-significant improvement in the total score at the end of our study compared to its mean level at the start of the study (22.8 ± 13.5 with P > 0.05).

CONCLUSION

The Mediterranean diet was safe and associated with significant improvement in IBS scores in children and adolescent patients with IBS.

Plasma Lipid Mediators Associate With Clinical Outcome After Successful Endovascular Thrombectomy in Patients With Acute Ischemic Stroke

Background

Neuroinflammatory response contributes to early neurological deterioration (END) and unfavorable long-term functional outcome in patients with acute ischemic stroke (AIS) who recanalized successfully by endovascular thrombectomy (EVT), but there are no reliable biomarkers for their accurate prediction. Here, we sought to determine the temporal plasma profiles of the bioactive lipid mediators lipoxin A4 (LXA4), resolvin D1 (RvD1), and leukotriene B4 (LTB4) for their associations with clinical outcome.

Methods

We quantified levels of LXA4, RvD1, and LTB4 in blood samples retrospectively and longitudinally collected from consecutive AIS patients who underwent complete angiographic recanalization by EVT at admission (pre-EVT) and 24 hrs post-EVT. The primary outcome was unfavorable long-term functional outcome, defined as a 90-day modified Rankin Scale score of 3-6. Secondary outcome was END, defined as an increase in National Institutes of Health Stroke Scale (NIHSS) score ≥4 points at 24 hrs post-EVT.

Results

Eighty-one consecutive AIS patients and 20 healthy subjects were recruited for this study. Plasma levels of LXA4, RvD1, and LTB4 were significantly increased in post-EVT samples from AIS patients, as compared to those of healthy controls. END occurred in 17 (20.99%) patients, and 38 (46.91%) had unfavorable 90-day functional outcome. Multiple logistic regression analyses demonstrated that post-EVT levels of LXA4 (adjusted odd ratio [OR] 0.992, 95% confidence interval [CI] 0.987-0.998), ΔLXA4 (adjusted OR 0.995, 95% CI 0.991-0.999), LTB4 (adjusted OR 1.003, 95% CI 1.001-1.005), ΔLTB4 (adjusted OR 1.004, 95% CI 1.002-1.006), and post-EVT LXA4/LTB4 (adjusted OR 0.023, 95% CI 0.001-0.433) and RvD1/LTB4 (adjusted OR 0.196, 95% CI 0.057-0.682) ratios independently predicted END, and post-EVT LXA4 levels (adjusted OR 0.995, 95% CI 0.992-0.999), ΔLXA4 levels (adjusted OR 0.996, 95% CI 0.993-0.999), and post-EVT LXA4/LTB4 ratio (adjusted OR 0.285, 95% CI 0.096-0.845) independently predicted unfavorable 90-day functional outcome. These were validated using receiver operating characteristic curve analyses.

Conclusions

Plasma lipid mediators measured 24 hrs post-EVT were independent predictors for early and long-term outcomes. Further studies are needed to determine their causal-effect relationship, and whether the imbalance between anti-inflammatory/pro-resolving and pro-inflammatory lipid mediators could be a potential adjunct therapeutic target.

Aspirin sensitivity of PIK3CA-mutated Colorectal Cancer: potential mechanisms revisited

PIK3CA mutations are amongst the most prevalent somatic mutations in cancer and are associated with resistance to first-line treatment along with low survival rates in a variety of malignancies. There is evidence that patients carrying PIK3CA mutations may benefit from treatment with acetylsalicylic acid, commonly known as aspirin, particularly in the setting of colorectal cancer. In this regard, it has been clarified that Class IA Phosphatidylinositol 3-kinases (PI3K), whose catalytic subunit p110α is encoded by the PIK3CA gene, are involved in signal transduction that regulates cell cycle, cell growth, and metabolism and, if disturbed, induces carcinogenic effects. Although PI3K is associated with pro-inflammatory cyclooxygenase-2 (COX-2) expression and signaling, and COX-2 is among the best-studied targets of aspirin, the mechanisms behind this clinically relevant phenomenon are still unclear. Indeed, there is further evidence that the protective, anti-carcinogenic effect of aspirin in this setting may be mediated in a COX-independent manner. However, until now the understanding of aspirin's prostaglandin-independent mode of action is poor. This review will provide an overview of the current literature on this topic and aims to analyze possible mechanisms and targets behind the aspirin sensitivity of PIK3CA-mutated cancers.

Specialized Pro-Resolving Mediators Derived from N-3 Polyunsaturated Fatty Acids: Role in Metabolic Syndrome and Related Complications

Significance: Metabolic syndrome (MetS) prevalence continues to grow and represents a serious public health issue worldwide. This multifactorial condition carries the risk of hastening the development of type 2 diabetes (T2D), non-alcoholic fatty liver disease (NAFLD), and cardiovascular diseases (CVD). Another troubling aspect of MetS is the requirement of poly-pharmacological therapy not devoid of side effects. Therefore, there is an urgent need for prospecting alternative nutraceuticals as effective therapeutic agents for MetS. Recent Advances: Currently, there is an increased interest in understanding the regulation of metabolic derangements by specialized pro-resolving lipid mediators (SPMs), especially those derived from the long chain n-3 polyunsaturated fatty acids. Critical Issues: The SPMs are recognized as efficient modulators that are capable of inhibiting the production of pro-inflammatory cytokines, blocking neutrophil activation/recruitment, and inducing non-phlogistic (anti-inflammatory) activation of macrophage engulfment and removal of apoptotic inflammatory cells and debris. The aim of the present review is precisely to first underline key concepts relative to SPM functions before focusing on their status and actions on MetS components (e.g., obesity, glucose dysmetabolism, hyperlipidemia, hypertension) and complications such as T2D, NAFLD, and CVD. Future Directions: Valuable data from preclinical and clinical investigations have emphasized the SPM functions and influence on oxidative stress- and inflammation-related MetS. Despite these promising findings obtained without compromising host defense, additional efforts are needed to evaluate their potential therapeutic applications and further develop practical tools to monitor their bioavailability to cope with cardiometabolic disorders. Antioxid. Redox Signal. 37, 54-83.