Proinflammatory Prostaglandin Research Articles

Inhibition of pro-inflammatory cytokines by homalolide A and homalomenol A isolated from rhizomes of Homalomena pendula.

Inflammation, a natural process of the innate immune system, involves elevated levels of various proinflammatory mediators, such as, nitric oxide (NO) and prostaglandin (PGE2), cytokines such as interleukin 6 (IL-6), interleukin 10 (IL-10) and tumor necrosis factor alpha (TNF-α), and enzymes including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). This study investigated the anti-inflammatory effects of homalolide A (1) and homalomenol A (2), two sesquiterpenoids isolated from the rhizome of Homalomena pendula, on lipopolysaccharide (LPS)- stimulated macrophage cells. The results demonstrated that both 1 and 2 dose-dependently inhibited the production of PGE2, TNF-α and IL-6 in RAW 264.7 macrophages. Furthermore, 2 also stimulated IL-10 production in RAW 264.7 cells. Consistent with these findings, these compounds suppressed the LPS-stimulated protein levels of iNOS and COX-2 in RAW 264.7 cells. These results suggested that 1 and 2 could be effective candidates for ameliorating inflammatory-associated complications.

Impairment of neuronal tyrosine phosphatase STEP worsens post-ischemic inflammation and brain injury under hypertensive condition

Hypertension is associated with poor outcome and higher mortality in patients with ischemic stroke. The impairment of adaptive vascular mechanisms under hypertensive condition compromises collateral blood flow after arterial occlusion in patients with acute ischemic stroke resulting in hypoperfusion. The increased oxidative stress caused by hypoperfusion is thought to be a trigger for the rapid evolution of ischemic infarct volume under hypertensive condition. However, the cellular factors and pathways that contribute to the exacerbation of ischemic brain injury under hypertensive condition is not yet understood. The current study reveals that predisposition to hypertension leads to basal loss of function of the neuron-specific tyrosine phosphatase STEP, which plays a crucial role in neuroprotection against excitotoxic insult. The findings further show that a mild ischemic insult in hypertensive rats triggers an early onset and sustained activation of the neuronal extracellular signal regulated kinase (ERK MAPK), a member of the mitogen activated protein kinase family and a substrate of STEP. This leads to rapid increase in the activation of neuronal NF-κB, expression of neuronal cyclooxygenase-2 and subsequent biosynthesis of the pro-inflammatory mediator prostaglandin E2, resulting in rapid morphological transformation of microglia to the pro-inflammatory state and subsequent exacerbation of ischemic brain injury. Restoration of STEP signaling with intravenous administration of a STEP-derived peptide mimetic reduces the pro-inflammatory response in neurons, activation of microglia, and ischemic brain injury. The findings suggest that the basal loss of STEP function under hypertensive condition contributes to the exacerbation of ischemic brain injury by enhancing post-ischemic inflammatory response. The study not only presents a novel role of STEP in regulating neuroimmune communication but also highlights the therapeutic potential of a STEP-mimetic in mitigating ischemic brain damage under hypertensive condition.

Cannabidiol exerts antipyretic effects by downmodulating inflammatory mediators in LPS-induced fever

Contrasting to tetrahydrocannabinol (THC), cannabidiol (CBD) has virtually no psychoactive effects and thus presents a minor risk for abuse. Furthermore, emerging preclinical and clinical evidence indicates that CBD exerts several beneficial pharmacological effects, including anti-inflammatory and antioxidant properties. Even though fever is one of the responses associated with systemic inflammation, no previous study assessed the putative impact of CBD on lipopolysaccharide (LPS)-induced fever. The present study aimed to evaluate whether CBD exerts effects on febrile responses, by modulating the hypothalamic-pituitary-adrenal (HPA) axis, and the inflammatory reflex, in this response. CBD caused no change in euthermic mice, indicating that it does not alter euthermia. Conversely, CBD blunted all the assessed systemic inflammation parameters including fever (a hallmark of infection), plasma pro-inflammatory cytokines and prostaglandin E2 (PGE2) surges, and hypothalamic PGE2 (the proximal mediator of fever) synthesis. Moreover, CBD also reduced LPS-induced increase in plasma corticosterone levels and spleen TNF-α. These data are consistent with the notion that CBD has antipyretic effects, reducing peripheral febrigenic signaling (plasma pro-inflammatory cytokines levels), and eventually down-modulating hypothalamic PGE2 production, possibly in a corticosterone- and inflammatory reflex-dependent manner.

Prostaglandin E2 suppresses KCNH1 gene expression and inhibits the proliferation of CaSki cervical cells through its four prostanoid PTGER subtypes

The main risk factor for cervical cancer is the persistent infection of high-risk HPV subtypes, notably HPV16. Another contributing factor is proinflammatory prostaglandin E2 (PGE2), a lipid abundantly found in seminal fluid. PGE2, along with its receptors (PTGER1-4), contributes to cancer development; however, its specific role in the proliferation of cervical cancer models with high HPV16 copy numbers remains unclear. In this study, we investigated the effects of PGE2 on the proliferation of CaSki cells, a cell line with a high HPV16 viral load. Surprisingly, PGE2 inhibited CaSki cell proliferation, while it increased the proliferation of SiHa, HeLa, and C-33 A cervical cancer cells. The effect of PGE2 on CaSki cell proliferation was specific, as estradiol increased cell growth. Furthermore, PGE2 suppressed expression and promoter activity of the cervical tumoral marker KCNH1. To discern the specific role of each receptor in cell proliferation, we generated stable CaSki cell lines overexpressing each receptor alongside control cells with an empty vector. Notably, PGE2 significantly inhibited cell proliferation in all stable transfected CaSki cells, suppressing oncogenic KCNH1 expression and its promoter activity. In conclusion, our findings indicate that PGE2 inhibits the proliferation of CaSki cervical cancer cells with a high HPV16 load, at least in part, by suppressing the expression of the oncogenic KCNH1 gene.

Modeling enzyme competition in eicosanoid metabolism in macrophage cells using a cybernetic framework

Cellular metabolism is a complex process involving the consumption and production of metabolites, as well as the regulation of enzyme synthesis and activity. Modeling of metabolic processes is important to understand the underlying mechanisms, with a wide range of applications in metabolic engineering and health sciences. Cybernetic modeling is a powerful technique that accounts for unknown intricate regulatory mechanisms in complex cellular processes. It models regulation as goal-oriented, where the levels and activities of enzymes are modulated by the cybernetic control variables to achieve the cybernetic objective. This study used cybernetic model to study the enzyme competition between arachidonic acid (AA) and eicosapentaenoic acid (EPA) metabolism in murine macrophages. AA and EPA compete for the shared enzyme cyclooxygenase. Upon external stimuli, AA produces proinflammatory 2-series prostaglandins and EPA metabolizes to antiinflammatory 3-series prostaglandins, where proinflammatory and antiinflammatory responses are necessary for homeostasis. The cybernetic model adequately captured the experimental data for control and EPA-supplemented conditions. The model is validated by performing an F-test, conducting leave-one-out-metabolite cross-validation, and predicting an unseen experimental condition. The cybernetic variables provide insights into the competition between AA and EPA for the cyclooxygenase enzyme. Predictions from our model suggest that the system undergoes a switch from a predominantly proinflammatory state in the control to an antiinflammatory state with EPA-supplementation. The model can also be used to analytically determine the AA and EPA concentrations required for the switch to occur. The quantitative outcomes enhance understanding of proinflammatory and antiinflammatory metabolism in RAW 264.7 macrophages.

Restoration of ARA metabolic disorders in vascular smooth muscle cells alleviates intimal hyperplasia

Intimal hyperplasia (IH) is an innegligible issue for patients undergoing interventional therapy. The proliferation and migration of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor-BB (PDGF-BB) are critical events in the development of IH. While the exact mechanism and effective target for IH needs further investigation. Metabolic disorders of arachidonic acid (ARA) are involved in the occurrence and progression of various diseases. In this study, we found that the expressions of soluble epoxide hydrolase (sEH) and cyclooxygenase-2 (COX-2) were significantly increased in the VSMCs during balloon injury-induced IH. Then, we employed a COX-2/sEH dual inhibitor PTUPB to increase the concentration of epoxyeicosatrienoic acids (EETs) while prevent the release of pro-inflammatory prostaglandins. Results showed that PTUPB treatment significantly reduced neointimal thickening induced by balloon injury in rats in vivo and inhibited PDGF-BB-induced proliferation and migration of VSMCs in vitro. Our results showed that PTUPB may reverse the phenotypic transition of VSMCs by inhibiting Pttg1 expression. In conclusion, we found that the dysfunction of ARA metabolism in VSMCs contributes to IH, and the COX-2/sEH dual inhibitor PTUPB attenuates IH progression by reversing the phenotypic switch in VSMC through the Sirt1/Pttg1 pathway.

Anti-Inflammatory Potential of Pygeum africanum Bark Extract: An In Vitro Study of Cytokine Release by Lipopolysaccharide-Stimulated Human Peripheral Blood Mononuclear Cells.

Pygeum africanum bark has been shown to inhibit the production of pro-inflammatory prostaglandins in the prostate and reduces the production of leukotrienes and other 5-lipoxygenase (5-LO) metabolites. It has been suggested that inflammation plays an important role in the pathophysiology of benign prostatic hyperplasia (BPH). Data from clinical trials have shown that P. africanum improves the symptoms and objective measures of BPH. This in vitro study aimed to assess the anti-inflammatory potential of a proprietary Pygeum bark standardized extract (Prunera®) on cytokine release from lipopolysaccharide-stimulated human peripheral blood mononuclear cells (PBMCs). PBMCs were obtained from four donors, and a bead-based assay (ProcartaPlex™ panel) was used for the detection and quantitation of cytokines. Pygeum africanum bark standardized extract (PABE) induced a statistically significant decrease (p < 0.05) of IL-6 in three donors. Other effects were as follows: IL-2 was lowered in all donors in the absence of a clear dose-response relationship; IL-4, IL-5, IL-9, and IL-13 levels were decreased in most donors; IL-22 levels seemed to be suppressed only for donor 4 at lower and medium concentrations; and IL-27 and TNF-α levels decreased at all PABE concentrations in all donors. The anti-inflammatory effect of PABE, particularly the reduction in IL-6 as a marker of inflammation, supports the potential use of this natural compound in the management of BPH and other conditions in which pro-inflammatory cytokines are involved in their underlying pathophysiological mechanisms.

(096) UNDERSTANDING THE RELATIONSHIP BETWEEN CHRONIC PAIN AND DEPRESSION IN LOCALIZED PROVOKED VULVODYNIA

Abstract Introduction Localized provoked vulvodynia (LPV) is a disease characterized by chronic pain in the vulva in response to touching the vulvar vestibular epithelium. As with other chronic pain disorders, vulvodynia is often found accompanied with depression, and depressive symptoms aggravate pain severity and persistence. While there is clear evidence of a connection between chronic vulvar pain and depression, the mechanism of this bidirectional relationship is largely unknown. Accumulating evidence suggests that inflammation plays a central role in depression. Since the pathophysiology of LPV also involves inflammation, we aim to better understand these relationships by pharmacologically inhibiting the enzyme that plays a key role in both inflammation and depression: soluble epoxide hydrolase (sEH). Objective To elucidate the role of sEH in localized provoked vulvodynia, which might be involved in the chronic pain and depression comorbidity prevalent in vulvodynia patients, and discuss the clinical significance of using sEH inhibitors, such as 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), for patients suffering from this condition. Methods Vulvar punch biopsies obtained from painful sites within the vulvar vestibule and non-painful sites within the external vulva of 6 LPV patients and 6 age/race-matched healthy controls were used to generate a library of primary fibroblast strains. Cells were treated with the inflammatory instigator interleukin-1β (IL-1β) and TPPU. Quantitative PCR, Western blotting, and enzyme-linked immunosorbent assays were used to assess the effects of sEH inhibition. Statistical analysis was performed using GraphPad Prism 10.0.2. Comparisons among groups were performed using the one-way analysis of variance (ANOVA) or two-way ANOVA, followed by post-hoc Tukey test. Results Vulvodynia patients produce increased levels of pro-inflammatory cytokines, namely interleukin-6 (IL-6) and prostaglandin E2 (PGE2), when compared with controls. Interestingly, mRNA (P = 0.0091) and protein (P = 0.0198) levels of sEH were significantly lower in the painful vestibule of these patients. When sEH was inhibited with TPPU, we observed a significant decrease in IL-6 levels (P = &amp;lt;0.0001), but not PGE2 (P = 0.6452). These preliminary findings are of fundamental importance as cytokines can directly contribute to the development of depressive symptoms. Conclusions Patients with vulvodynia are more likely to develop depressive symptoms than patients without vulvar pain. Likewise, patients with depression are more likely to develop vulvodynia than patients without depression. Our results suggest that sEH may play a role in this bidirectional mechanism, which could serve as a novel therapeutic target for chronic pain and depression comorbidity. Disclosure No.

Inflammatory bowel diseases and modern methods of their treatment

Chronic inflammatory bowel diseases are a group of diseases that still do not have a specific cause of their occurrence, are characterized by a particularly complex pathogenesis, a variety of clinical manifestations and a significant impact on the patient’s quality of life. Crohn’s disease and non-specific ulcerative colitis are diseases that run with the risk of severe exacerbations and can also lead to the patient’s disability. The main task in the treatment of inflammatory bowel diseases is the initiation of the remission stage and its long-term maintenance. For this, several groups of drugs are used, among which the drug of the first line of therapy is Mesalazine (Mesacol®), its effect on the intestinal wall consists in preventing the development of the inflammatory process by reducing the synthesis of pro-inflammatory prostaglandins and leukotrienes, slowing down the migration, degranulation and phagocytosis of neutrophils. In addition, mesalazine neutralizes free radicals, which increases the protective effect on the intestinal wall.

The Anti-Inflammatory Effect of Nigella sativa Toothpaste on Porphyromonas gingivalis Bacteria Through Decreased TNF-α, MMP-9, PGE-2 Expression in Wistar Rats.

The main principle in preventing periodontal disease is to improve oral hygiene. The bacteria that cause the onset of periodontal disease, one of which is the Porphyromonas gingivalis bacterium, causes inflammation. Persistent inflammation causes tissue damage and alveolar bone resorption by secreting proinflammatory cytokines, matrix metalloproteinase-9 (MMP-9), prostaglandin E2 (PGE-2), and anti-inflammatory cytokines. In this case, preventive treatment is needed, such as using toothpaste that contains anti-inflammatories so that the progression of the disease does not get worse. The traditional ingredient currently being developed is Nigella sativa, which has anti-inflammatory properties. Therefore, this study analyzes the potential of toothpaste containing Nigella sativa on the expression of tumor necrosis factor-α (TNF-α), MMP-9, and PGE-2 in the Wistar rat model induced by Porphyromonas gingivalis bacteria. This study aims to prove the potential of Nigella sativa toothpaste to decrease the expression of PGE-2, TNF-α, and MMP-9 in the gingiva of rats induced by Porphyromonas gingivalis bacteria. Forty-five healthy male Wistar rats were used, consisting of the negative control group, which was only injected with Porphyromonas gingivalis bacteria ATCC3322. The positive control group was given enzyme toothpaste, and the treatment group was assigned 1 mg of Nigella sativa paste using a microbrush for 30 seconds on the gingiva incisors mandibular with a circular motion, given two times a day for a week. Immunohistochemical to see the expression of TNF-α, PGE-2, and MMP-9. Parametric comparative analysis using a one-way analysis of variance test was performed to analyze differences between groups. Nigella sativa toothpaste significantly reduced proinflammatory cytokines, as seen through the expression of TNF-α, PGE-2, and MMP-9 on days 3, 5, and 7 (p <0.05). In the limit of studied animal model, this trial indicates that giving toothpaste with black seed extract (Nigella sativa) could inhibit inflammatory mediators, as seen from the decreased expression of MMP-9, TNF-α, and PGE-2 seen from the 3rd, 5th, and 7th days.

Finding the research gap of the potential anti-inflammatory activity of cocoa (Theobroma cacao L.) through systematic literature review

The use of conventional drugs in treating inflammation has various side effects, and thus it is necessary to have an alternative anti-inflammatory agent that is effective and safe. Cocoa (Theobroma cacao L.) is one of the agricultural products with a high content of polyphenols, especially flavan-3-ols potentially used as an anti-inflammatory agent. The purpose of this research is to investigate the research gap of the potential antiinflammatory activity of cocoa based on the published literatures. The systematic method of synthesizing the review follows the guidelines of the PRISMA Statement 2020 using the PICOS literature search strategy. The results of this study showed that the positive effect of cocoa on inflammation indicated by 44 out of 72 biomarkers (61.11%). Flavan-3- ols can effectively reduce inflammation by reducing the activation of transcripts that regulate pro-inflammatory cytokines (NF-kB), prostaglandins, and NO. The antiinflammatory effect was effectively found in different groups, i.e., subjects without health issue (healthy subject), subjects with some health problems record and subjects with obesity. Nevertheless, it was found in the previous researches that the manifest of cocoaderived products as well as the biomarkers for determining the anti-inflammatory effect of cocoa still vary. Also, there is no study investigating the anti-inflammatory effect of cocoa on different age group. Therefore, further researches are required in this area to complete the puzzle of information regarding the potential anti-inflammatory activity of cocoa.

Anti-Inflammatory Efficacy of Resveratrol-Enriched Rice Callus Extract on Lipopolysaccharide-Stimulated RAW264.7 Macrophages

Resveratrol and its derivative piceid exhibit a wide spectrum of health-promoting bioactivities. A resveratrol-enriched variety of Dongjin rice (DJ526) has been developed by transfection of a resveratrol biosynthesis gene, and increased resveratrol content has been confirmed in seeds following germination. In the current study, these resveratrol-enriched seeds were induced to produce callus, and callus extracts were evaluated for in vitro anti-inflammatory activity. Callus cultures contained greater amounts of resveratrol and piceid than DJ526 seeds, and treatment with DJ526 callus extract significantly reduced the lipopolysaccharide (LPS)-induced production of proinflammatory mediators nitric oxide and prostaglandin E2 by RAW264.7 macrophages. The inflammation-related nuclear factor kappa B and mitogen-activated protein kinase pathways were also inhibited in DJ526 callus extract-treated RAW264.7 cells, resulting in downregulation of proinflammatory factor genes COX-2, iNOS, IL-1β, IL-6, and TNF-α. Expression of the LPS-binding toll-like receptor-4 was also markedly reduced in DJ526 callus extract-treated cells compared to DJ callus extract-treated cells. These findings demonstrate increased resveratrol and piceid content by callus culture of DJ526 rice seeds and the potent anti-inflammatory activity of resveratrol-enriched callus extract.

MiR-515-5p targeting Toll-like receptor 4 regulates myeloid differentiation primary response gene 88/nuclear factor-kappa B pathway to inhibit apoptosis and inflammatory response of osteoarthritis chondrocytes

To explore the molecular mechanism of miR-515-5p in inhibiting chondrocyte apoptosis and alleviating inflammatory response in osteoarthritis (OA). Human cartilage cell line C28/I2 was cultured in vitro and treated with 10 ng/mL interleukin 1β (IL-1β) for 24 hours to construct an in vitro OA model. C28/I2 cells were transfected with miR mimics, mimics negative control (NC), over expression (oe)-NC, and oe-Toll-like receptor 4 (TLR4), respectively, and then treated with 10 ng/mL IL-1β for 24 hours to establish OA model. Cell proliferation capacity was detected by cell counting kit 8 and 5-Ethynyl-2'-deoxyuridine, cell apoptosis and cell cycle were detected by flow cytometry, and B-cell lymphoma 2 protion (Bcl-2), Bcl-2-associated X protein (Bax), cleaved-Caspase-3, TLR4, myeloid differentiation primary response gene 88 (MyD88), p65 and phosphorylated p65 (p-p65) protein expression levels were detected by Western blot. Real-time fluorescence quantitative PCR was used to detect mRNA expression levels of miR-515-5p and TLR4, and ELISA was used to detect pro-inflammatory factor prostaglandin E2 (PGE2), tumor necrosis factor α (TNF -α), and IL-6 levels in cell supernatant. The potential binding sites between miR-515-5p and TLR4 were predicted by BiBiServ2 database, and the targeting relationship between miR-515-5p and TLR4 was verified by dual luciferase reporting assay. After the treatment of C28/I2 cells with IL-1β, the expressions of miR-515-5p and Bcl-2 protein and the proliferation ability of C28/I2 cells significantly reduced. The expression levels of Bax and cleaved-Caspase-3 protein, the levels of pro-inflammatory factors (PGE2, TNF-α, IL-6) in the supernatant of C28/I2 cells, and the apoptosis of C28/I2 cells significantly increased. In addition, the proportion of the cells at S phase and G 2 phase decreased significantly, and the proportion of cells at G 1 phase increased significantly, suggesting that the cell cycle was blocked after IL-1β treatment. After transfection with miR mimics, the expression level of miR-515-5p in the cells significantly up-regulated, partially reversing the apoptosis of OA chondrocytes induced by IL-1β, and alleviating the cycle arrest and inflammatory response of OA chondrocytes. After treating C28/I2 cells with IL-1β, the mRNA and protein levels of TLR4 significantly increased. Overexpression of miR-515-5p targeted inhibition of TLR4 expression and blocked activation of MyD88/nuclear factor κB (NF-κB) pathway. Overexpression of TLR4 could partially reverse the effect of miR mimics on IL-1β-induced apoptosis and inflammation of OA chondrocytes. miR-515-5p negatively regulates the expression of TLR4, inhibits the activation of MyD88/NF-κB pathway and apoptosis of OA chondrocytes, and effectively alleviates the inflammatory response of the cells.

86 Evaluation of dietary Saccharomyces cerevisiae fermentation product on markers of joint inflammation in young, exercising horses following an intra-articular lipopolysaccharide challenge

Abstract Including Saccharomyces cerevisiae fermentation product (SCFP) into the diets of young, exercising horses may prolong their performance career by optimizing the intra-articular environment. Our objective was to evaluate the effect of dietary SCFP on joint inflammation in yearlings undergoing regular exercise, challenged with intra-articular lipopolysaccharide (LPS). Thirty Quarter Horse yearlings (374 ± 25 kg BW; 562 ± 16 d of age; 15 fillies and 15 geldings) were used in a 60-d study to test the hypothesis that dietary SCFP (TruEquine C, Diamond V Mills, Inc.) ameliorates joint inflammation following an acute inflammatory insult. Horses were stratified by BW, age, sex, and randomly assigned to dietary treatments (n = 10/treatment): Control (0), 46, or 92 mg/kg BW SCFP. Treatments were top-dressed onto a custom-formulated concentrate void of added microbials offered at 1% BW/d (as-fed) every 12 h. Horses were individually stalled (3.6 m × 7.3 m) and offered ad libitum Coastal bermudagrass hay. Using a free-stall exerciser, horses were exercised following a progressive workload regimen for 30 min/d, 5 d/wk. On d 46, all horses underwent an intra-articular LPS challenge where each horse had one radial carpal joint randomly assigned to receive either 0.8 mL of a 0.5 ng LPS solution or sterile lactated Ringer’s solution (LRS) as a contralateral control. Synovial fluid samples were obtained pre-injection (h 0) and at 6, 12, 24, and 336 h post-injection and analyzed for prostaglandin E2 (PGE2), a pro-inflammatory prostaglandin via commercial ELISA, and for chemokine-concentration (signaling proteins that direct immune cells; CCL2, and CCL11) and cytokines (inflammatory mediators; TNFα and IL-10) using a multiplex platform via commercial laboratory. Non-normal data (PGE2, IL-10, and CCL2) were log transformed, and all markers were analyzed using MIXED procedure of SAS v9.4. Mean separation was achieved with orthogonal contrasts, and contralateral control carpi were used as a covariate across all hours. There was no effect of SCFP on synovial logPGE2 (P = 0.42), logCCL2 (P = 0.90), CCL11 (P = 0.26), or logIL-10 (P = 0.23). However, there was a treatment × hour interaction for CCL11 (P = 0.04) where the Control had increased concentrations compared with SCFP treatment groups at 6 h post-injection. Furthermore, logIL-10 also had a treatment × hour interaction (P = 0.05) where the 46mg/kg BW group had decreased concentrations at h 12 compared with the Control and 92mg/kg BW group. The main effect of treatment for TNFα (P = 0.04) revealed that the 92mg/kg BW group had less concentrations than the 46mg/kg BW group and tended to have less concentrations than the Control group across all hours. Results indicate that SCFP may help mitigate inflammation markers following an acute intra-articular inflammatory insult.

The Effect of Acute Knee Injuries and Related Knee Surgery on Serum Levels of Pro- and Anti-inflammatory Lipid Mediators and Their Associations With Knee Symptoms

Background: Despite an acute knee injury being a major risk factor for osteoarthritis, the factors that initiate and maintain this risk of longer-term knee symptoms are poorly understood. Bioactive lipids derived from omega-3 and -6 polyunsaturated fatty acids have key roles in the regulation of the inflammatory response and have been linked to joint damage and osteoarthritis pain in translational models. Hypothesis: There would be associations between systemic levels of bioactive lipids and knee symptoms longitudinally after an acute knee injury and related knee surgery. Study Design: Controlled laboratory study. Methods: This study analyzed a subset of young, active adults who had sustained an acute knee injury (recruited via a surgical care pathway) and healthy age- and sex-matched controls. Surgery, if performed, was conducted after the baseline serum sample was taken and before the 3-month and 2-year visits. Liquid chromatography–tandem mass spectrometry of 41 bioactive lipids was carried out in sera of (1) 47 injured participants (median age, 28 years) collected at baseline (median, 24 days after injury), 3 months, and 2 years, along with the Knee injury and Osteoarthritis Outcome Score, and (2) age- and sex-matched controls. Results: Levels of the omega-3 polyunsaturated fatty acids eicosapentaenoic acid (P≤ .0001) and docosahexaenoic acid (P≤ .0001) and the pro-resolving lipid mediators 17– and 14–hydroxydocosahexaenoic acid, and 18-hydroxyeicosapentaenoic acid were all significantly greater at baseline in injured participants compared with the later time points and also higher than in healthy controls (P = .0019 and P≤ .0001, respectively). Levels of pro-inflammatory prostaglandins E2 and D2, leukotriene B4, and thromboxane B2 were significantly lower at baseline compared with the later time points. Higher levels of 8,9–, 11,12–, and 14,15–dihydroxyeicosatrienoic acid (DHET) were cross-sectionally associated with more severe knee pain/symptoms according to the Knee injury and Osteoarthritis Outcome Score at 2 years (P = .0004, R2 = 0.251; P = .0002, R2 = 0.278; and P = .0012, R2 = 0.214, respectively). Conclusion: The profile of pro-resolving versus pro-inflammatory lipids at baseline suggests an initial activation of pro-resolution pathways, followed by the later activation of pro-inflammatory pathways. Clinical Relevance: In this largely surgically managed cohort, the association of soluble epoxide hydrolase metabolites, the DHETs, with more severe knee symptoms at 2 years provides a rationale for further investigation into the role of this pathway in persisting knee symptoms in this population, including potential therapeutic strategies.

Association between neutrophil to lymphocyte ratio and inflammatory biomarkers in patients with a first episode of psychosis

Neutrophil to lymphocyte ratio (NLR) has been proposed as an emerging marker of the immune system alterations in psychotic disorders. However, it is not entirely clear whether NLR elevation is a characteristic of the psychotic disorder itself, which inflammatory pathways activation is detecting, or which possible confounding variables could alter its interpretation.We aimed to analyze the relationship of NLR values with a panel of inflammatory and oxidative/nitrosative stress biomarkers and main potential confounding factors in a well-characterized cohort of 97 patients with a first episode of psychosis (FEP) and 77 matched healthy controls (HC).In the FEP group, NLR values presented a moderate, positive correlation with the pro-inflammatory mediator Prostaglandin E2 levels (r = 0.36, p < 0.001) and a small but significant, positive correlation with cannabis use (r = 0.25, p = 0.017). After controlling for cannabis use, the association between NLR and PGE2 remained significant (beta = 0.31, p = 0.012). In the HC group, NLR values negatively correlated with body mass index (BMI, r = −0.24, p = 0.035) and positively correlated with tobacco use (r = 0.25, p = 0.031).These findings support a relationship between the elevation of NLR values and an elevated expression of proinflammatory pathways related to stress response in patients with a FEP. In addition, our study highlights the importance of considering variables such as cannabis or tobacco consumption, and BMI when interpreting the results of studies aimed to establish a clinical use of NLR. These considerations may help future research to use NLR as a reliable biomarker to determine immune system status in this population.

Abstract WP322: GluN2A-NMDAR Mediated Increased Neuronal Prostaglandin E2 Release and Microglial Activation Exacerbates Ischemic Brain Injury Under Hyperhomocysteinemic Condition

Hyperhomocysteinemia (Hhcy), a metabolic disorder is recognized as a risk factor for ischemic stroke. However, the impact of Hhcy on stroke outcome is not known. Using a rodent model of experimental stroke, we recently showed that predisposition to Hhcy exacerbates ischemic brain injury. The findings also showed that Hhcy triggers GluN2A subunit containing NMDA receptor (GluN2A-NMDAR) stimulation that act in conjunction with ischemia-induced pathways involving GluN2B subunit containing NMDAR (GluN2B-NMDAR) stimulation to enhance stroke pathology. The current study evaluated whether GluN2A-NMDAR-mediated increased expression of cyclooxygenase-2 (COX-2) and excessive release of the pro-inflammatory mediator prostaglandin E2 (PGE2) from neurons results in increased microglial activation and exacerbated ischemic brain injury. HHcy was induced by implantation of Alzet pumps with L-homocysteine in adult male Wistar rats. Cerebral ischemia was induced by middle cerebral artery occlusion (60 min) in control and Hhcy rats. In a subset of Hhcy rats, NVP-AAM077, a pharmacological inhibitor of GluN2A-NMDAR was injected intravenously at the onset of stroke. At specified times following reperfusion, brain tissues were processed for FluroJade staining, immunoblotting with COX2 antibody, immunohistochemistry with COX2/NeuN and Iba1 antibodies, prostaglandin E2 (PGE2) assay and RT-PCR. FluroJade staining shows an early onset and exacerbation of ischemic injury in Hhcy rats. This involves increased expression of COX-2 in neurons, release of PGE2, and a shift in microglial morphology from ramified state to active amoeboid state, 6h after reperfusion. Administration of NVP-AAM077 attenuates the increase in COX2 expression and PGE2 levels as well as microglial activation. The findings demonstrate that an early onset of neuroinflammatory response mediated through GluN2A-NMDAR stimulation could contribute to the exacerbation of ischemic brain injury under Hhcy conditions. As GluN2A-NMDAR stimulation is primarily involved in promoting synaptic plasticity, neuronal growth, and survival, establishing their role in promoting neuroinflammatory response could lead to a paradigm shift in our understanding of the consequences of NMDAR signaling.

Human Coronary Artery Endothelial Cell Response to Porphyromonas gingivalis W83 in a Collagen Three-Dimensional Culture Model.

P. gingivalis has been reported to be an endothelial cell inflammatory response inducer that can lead to endothelial dysfunction processes related to atherosclerosis; however, these studies have been carried out in vitro in cell culture models on two-dimensional (2D) plastic surfaces that do not simulate the natural environment where pathology develops. This work aimed to evaluate the pro-inflammatory response of human coronary artery endothelial cells (HCAECs) to P. gingivalis in a 3D cell culture model compared with a 2D cell culture. HCAECs were cultured for 7 days on type I collagen matrices in both cultures and were stimulated at an MOI of 1 or 100 with live P. gingivalis W83 for 24 h. The expression of the genes COX-2, eNOS, and vWF and the levels of the pro-inflammatory cytokines thromboxane A2 (TXA-2) and prostaglandin I2 (PGI2) were evaluated. P. gingivalis W83 in the 2D cell culture increased IL-8 levels at MOI 100 and decreased MCP-1 levels at both MOI 100 and MOI 1. In contrast, the 3D cell culture induced an increased gene expression of COX-2 at both MOIs and reduced MCP-1 levels at MOI 100, whereas the gene expression of eNOS, vWF, and IL-8 and the levels of TXA2 and PGI2 showed no significant changes. These data suggest that in the collagen 3D culture model, P. gingivalis W83 induces a weak endothelial inflammatory response.

Prostaglandin E2 Boosts the Hyaluronan-Mediated Increase in Inflammatory Response to Lipopolysaccharide by Enhancing Lyve1 Expression.

Macrophages are a highly versatile and heterogenic group of immune cells, known for their involvement in inflammatory reactions. However, our knowledge about distinct subpopulations of macrophages and their specific contribution to the resolution of inflammation remains incomplete. We have previously shown, in an in vivo peritonitis model, that inhibition of the synthesis of the pro-inflammatory lipid mediator prostaglandin E2 (PGE2) attenuates efficient resolution of inflammation. PGE2 levels during later stages of the inflammatory process further correlate with expression of the hyaluronan (HA) receptor Lyve1 in peritoneal macrophages. In the present study, we therefore aimed to understand if PGE2 might contribute to the regulation of Lyve1 and how this might impact inflammatory responses. In line with our in vivo findings, PGE2 synergized with dexamethasone to enhance Lyve1 expression in bone marrow-derived macrophages, while expression of the predominant hyaluronan receptor CD44 remained unaltered. PGE2-mediated Lyve1 upregulation was strictly dependent on PGE2 receptor EP2 signaling. While PGE2/dexamethasone-treated macrophages, despite their enhanced Lyve1 expression, did not show inflammatory responses upon stimulation with low (LMW) or high-molecular-weight hyaluronan (HMW)-HA, they were sensitized towards LMW-HA-dependent augmentation of lipopolysaccharide (LPS)-induced inflammatory responses. Thus, Lyve1-expressing macrophages emerged as a subpopulation of macrophages integrating inflammatory stimuli with extracellular matrix-derived signals.

Eugenia supra-axillaris Essential Oil and Its Nanoemulsion: Chemical Characterization, In Vivo Anti-Inflammatory, Analgesic, and Antipyretic Activities

The use of standard synthetic medications to treat inflammatory illnesses is associated with several negative effects. It has been shown that medicinal plants and their by-products are useful for safely treating inflammation. Herein, the essential oil of Eugenia supra-axillaris (family: Myrtaceae, ESA-EO) was isolated and further chemically characterized by GC-MS, and then, its nanoemulsion (ESA-EO-NE) was prepared. In addition, the anti-inflammation against the carrageenan-induced rats, the analgesic, and antipyretic activities of ESA-EO and ESA-EO-NE were evaluated in rats. Forty-three compounds were identified via GC-MS and categorized as mono- (61.38%) and sesquiterpenes (34.86%). d-limonene (32.82%), α-pinene (24.33%), germacrene-D (4.88%), α-humulene (4.73%), α-cadinol (3.39%), and trans-caryophyllene (3.15%) represented the main components. The administration of ES-EO and ES-EO-NE (50 and 100 mg/kg) demonstrated strong, dose-dependent inflammation inhibition capabilities in the model of rat paw edema, in comparison with both the reference drug and control. Reduced levels of malondialdehyde (MDA), increased levels of glutathione (GSH), and decreased levels of the proinflammatory cytokines (TNF-α), nitrosative (NO), and prostaglandin E2 (PGE2) in paw tissues all contributed to these substantial reductions in inflammation. Moreover, the oral administration of ESA-EO and ESA-EO-NE (50 and 100 mg/kg) exhibited potent analgesic and antipyretic activities in rats. Although the higher dose of ESA-EO and ESA-EO-NE (100 mg/kg) displayed delayed anti-inflammatory activity, they have long-lasting inflammation inhibition with fast onset and long-standing analgesic effects better than reference drugs. Furthermore, the most effective antipyretic efficacy was provided by ESA-EO-NE (100 mg/kg). These results provide insight into the possible therapeutic application of ESA-EO and its nanoemulsion against various inflammatory and painful illnesses as well as hyperthermia ailments.