The importance of cyclooxigenase in dentistry: a narrative review

Aim: Cyclooxygenase enzymes (COX) catalyze the conversion of arachidonic acid to prostaglandins and thromboxanes during pain and inflammation conditions. These enzymes have also been linked to several other conditions and diseases, and hence, in dentistry, it is crucial to identify the processes that increase the levels of these mediators. This paper aims to describe the significance of COX in dental practice through a narrative review. Methods: Articles relating to COX upregulation published in English and Spanish over the last 51 years in databases such as EBSCO, Google Scholar, Science Direct, PubMed, and Web of Science; were analyzed. Results: A total of 115 articles demonstrating the relationship between COX upregulation and multiple conditions and diseases of importance in prosthodontics, periodontics, oral pathology, orthodontics, and endodontics were included. Conclusions: COX upregulation is related to inflammatory and malignant diseases in oral tissues, such as periodontitis, pulpitis, and oral cancer, nevertheless, its expression is advantageous in other fields of study such as orthodontics. Additionally, is well documented that dental materials provoke an undesired increase in COX expression, which could be a significant factor that directly affects pulpal health

Anti-inflammatory activity of Piper umbellatum Linn. leaf extracts

Background@#Earlier studies reported the anti-inflammatory activity in several species of Piper, and Piper umbellatum Linn. leaves containing some phytochemicals that are potent anti-inflammatory agents. However, there was no thorough investigation on the anti-inflammatory activity of the locally grown P. umbellatum in the Philippines. @*Objective@#The study aimed to determine the anti-inflammatory activity of Piper umbellatum leaves using in vitro and in vivo assays. @*Methodology@#Crude extracts were obtained from P. umbellatum leaves using polar and non-polar solvents. The anti-inflammatory activities of all crude extracts were determined using the carrageenan-induced paw edema test in mice and phytochemical analysis. The crude extract with the highest activity was partially purified using column chromatography. The fractions with similar TLC profile were pooled and tested for antiinflammatory activity. COX-1 and COX-2 enzyme inhibitory activity were determined in pooled fractions that showed initial activity in animal model. @*Results@#Among the crude extracts of P.umbellatum, the crude ethyl acetate extract exhibited a significant dose-dependent inhibition on paw edema test with doses of 500 mg/kg bw, 1,000 mg/kg bw and 1,500 mg/kg bw (p<0.05). Among the 20 pooled fractions (PF) collected from the ethyl acetate extract, PF58, PF60 and PF64 had the highest COX-2 enzyme inhibitions of 83.12 %, 84.78% and 77.47%, respectively (p<0.05). PF60 also exhibited the highest anti-inflammatory activity on paw edema with inhibitions of 62.45% at low dose (250 mg/kg bw) and 76.10 % at high dose (1,000 mg/kg bw) in mice. @*Conclusion@#The ethyl acetate extract of P. umbellatum leaves and its fraction-PF60 exhibited a significant anti-inflammatory activity in in vitro and in vivo assays and contained high amounts of total phenolic and total flavonoid.

Erupção pigmentar fixa à nimesulida comprovada por teste de contato / Fixed pigmented erythema from nimesulide proven by patch testing

A erupção pigmentar fixa (EPF) é uma reação cutânea adversa a drogas relativamente comum, envolvendo cerca de 10% de todas as reações de hipersensibilidade a medicamentos (RHM). Envolve uma reação imunológica não imediata, mediada por células T CD8+ sensibilizadas, relacionada ao mecanismo do tipo IVc na classificação de Gell e Coombs. Um dos grupos mais frequentemente implicados nesse tipo de reação é o dos antiinflamatórios. Relatamos o caso de um homem que, 24 horas após iniciar tratamento com nimesulida para lombalgia, apresentou um quadro de lesões cutâneas tipo máculas eritemato-violáceas bem delimitadas e disseminadas pelo corpo. A nimesulida é um fármaco anti-inflamatório não esteroidal (AINE) pertencente à classe das sulfonanilidas, que atua como inibidor seletivo da enzima da síntese de prostaglandina, a ciclo-oxigenase, inibindo preferencialmente a COX-2. O diagnóstico foi comprovado pela realização do teste de contato, também conhecido como patch test, que traduziu positividade na segunda leitura realizada após 72 horas da sua colocação.

Fixed pigmented erythema (FPE) is a relatively common adverse drug reaction, consisting of approximately 10% of all drug hypersensitivity reactions. It involves a non-immediate immune reaction mediated by sensitized CD8+ T cells and related to the type IVc mechanism in the Gell-Coombs classification. One of the groups most frequently involved in this type of reaction is that of anti-inflammatory drugs. We report the case of a man who, 24 hours after starting treatment with nimesulide for low back pain, presented with well-defined cutaneous lesions consisting of erythematous-violaceous macules and spread throughout the body. Nimesulide is a non-steroidal anti-inflammatory drug (NSAID) belonging to the sulfonanilide class that acts as a selective inhibitor of the prostaglandin synthesis enzyme, cyclooxygenase (COX), preferentially inhibiting COX-2. The diagnosis was confirmed by a patch test, which translated positively in the second reading performed 72 hours after its placement.

Anti-inflammatory effect of remifentanil in lipopolysaccharide–stimulated amniotic epithelial cells

BACKGROUND: Sometimes general anesthesia is required for dental surgery in pregnant women. Facial bone fractures or neck abscess should be treated immediately. Dental surgery, however, creates a stressful situation that can cause inflammation. Inflammatory responses are a well-known major cause of preterm labor and preterm birth. Here we demonstrate the effects of remifentanil on the factors related to preterm labor and its mechanism of action on amniotic-derived epithelial cells (WISH cells). METHODS: WISH cells were exposed to lipopolysaccharide (LPS) for 24 h and co-treated with various concentrations of remifentanil. MTT assays were performed to measure cell viability. To explain the effects of remifentanil on the factors related to inflammation in WISH cells, activation of nuclear factor kappa B (NF-κB) and p38 and the expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, cyclooxygenase (COX)2, and prostaglandin E (PGE)2 were quantified using western blotting and RT-PCR, respectively. RESULTS: Remifentanil did not affect WISH cell viability. In western blot analysis, co-treatment with remifentanil resulted in decreased phosphorylation of NF-κB, and expression of COX2 and PGE2 in LPS-induced inflammation, but the results were statistically significant only at low concentrations. Reduction of IL-1β and TNF-α expression was also observed with RT-PCR. CONCLUSION: Co-treatment with remifentanil does not affect the viability of WISH cells, but reduces the expression of the factors related to inflammation, which can induce uterine contraction and preterm labor. These findings provide evidence that remifentanil may inhibit uterine contraction and preterm labor in clinical settings.

Effect of Garcinia mangostana L. and propolis extracts on the inhibition of inflammation and alveolar bone loss in ligature-induced periodontitis in rats

The purpose of this study was to evaluate the effect of mangosteen extract complex (MEC; Garcinia mangostana L. and propolis extracts) on the inhibition of inflammation and prevention of alveolar bone loss using a ligature-induced periodontitis model. Rat molars were ligatured with silk, and 1 µg/mL of lipopolysaccharide of Porphyromonas gingivalis was injected into the buccal and palatal gingivae of the teeth with or without treatment with the MEC. Changes in the expression levels of prostaglandin E₂ (PGE₂), interleukin-8 (IL-8), inducible nitric oxide synthase (iNOS), matrix metalloproteinase-8 (MMP-8), cyclooxygenase (COX)-1, and COX-2 in gingival tissues were evaluated using enzyme-linked immunosorbent assays. Alveolar bone loss around the ligated molars was examined using micro-computed tomography. The expression levels of PGE₂, IL-8, iNOS, MMP-8, COX-1, and COX-2 in gingival tissues were significantly reduced in the group treated with a mixture of 16 µg of mangosteen extract powder and 544 µg of propolis extract powder (ligation [Lig] + lipopolysaccharide extracted from P. gingivalis KCOM 2804 [L] + MEC 1:34). Additionally, alveolar bone loss was significantly reduced in the Lig + L + MEC 1:34 group compared with that in other groups. These results indicate that the MEC could be useful in preventing and treating periodontitis.

Analgesic Effect of Toll-like Receptor 4 Antagonistic Peptide 2 on Mechanical Allodynia Induced with Spinal Nerve Ligation in Rats

Neuroinflammation is one of the key mechanisms of neuropathic pain, which is primarily mediated by the Toll-like receptor 4 (TLR4) signaling pathways in microglia. Therefore, TLR4 may be a reasonable target for treatment of neuropathic pain. Here, we examined the analgesic effect of TLR4 antagonistic peptide 2 (TAP2) on neuropathic pain induced by spinal nerve ligation in rats. When lipopolysaccharide (LPS)-stimulated BV2 microglia cells were treated with TAP2 (10 µM), the mRNA levels of proinflammatory mediators, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, cyclooxygenase (COX)-2, and inducible nitric oxide synthase (iNOS), were markedly decreased by 54–83% as determined by quantitative PCR (qPCR) analysis. Furthermore, when TAP2 (25 nmol in 20 µL PBS) was intrathecally administered to the spinal nerve ligation-induced rats on day 3 after surgery, the mechanical allodynia was markedly decreased for approximately 2 weeks in von Frey filament tests, with a reduction in microglial activation. On immunohistochemical and qPCR analyses, both the level of reactive oxygen species and the gene expression of the proinflammatory mediators, such as TNF-α, IL-1β, IL-6, COX-2, and iNOS, were significantly decreased in the ipsilateral spinal dorsal horn. Finally, the analgesic effect of TAP2 was reproduced in rats with monoiodoacetate-induced osteoarthritic pain. The findings of the present study suggest that TAP2 efficiently mitigates neuropathic pain behavior by suppressing microglial activation, followed by downregulation of neuropathic pain-related factors, such as reactive oxygen species and proinflammatory molecules. Therefore, it may be useful as a new analgesic for treatment of neuropathic pain.

Luteolin and luteolin-7-O-glucoside protect against acute liver injury through regulation of inflammatory mediators and antioxidative enzymes in GalN/LPS-induced hepatitic ICR mice

BACKGROUND/OBJECTIVES: Anti-inflammatory and antioxidative activities of luteolin and luteolin-7-O-glucoside were compared in galactosamine (GalN)/lipopolysaccharide (LPS)-induced hepatitic ICR mice. MATERIALS/METHODS: Male ICR mice (6 weeks old) were divided into 4 groups: normal control, GalN/LPS, luteolin, and luteolin-7-O-glucoside groups. The latter two groups were administered luteolin or luteolin-7-O-glucoside (50 mg/kg BW) daily by gavage for 3 weeks after which hepatitis was induced by intraperitoneal injection of GalN and LPS (1 g/kg BW and 10 µg/kg BW, respectively). RESULTS: GalN/LPS produced acute hepatic injury by a sharp increase in serum AST, ALT, and TNF-α levels, increases that were ameliorated in the experimental groups. In addition, markedly increased expressions of cyclooxygenase (COX)-2 and its transcription factors, nuclear factor (NF)-κB and activator protein (AP)-1, were also significantly attenuated in the experimental groups. Compared to luteolin-7-O-glucoside, luteolin more potently ameliorated the levels of inflammatory mediators. Phase II enzymes levels and NF-E2 p45-related factor (Nrf)-2 activation that were decreased by GalN/LPS were increased by luteolin and luteolin-7-O-glucoside administration. In addition, compared to luteolin, luteolin-7-O-glucoside acted as a more potent inducer of changes in phase II enzymes. Liver histopathology results were consistent with the mediator and enzyme results. CONCLUSION: Luteolin and luteolin-7-O-glucoside protect against GalN/LPS-induced hepatotoxicity through the regulation of inflammatory mediators and phase II enzymes.

Diverse characters of Brennan’s paw incision model regarding certain parameters in the rat / 대한통증학회지

BACKGROUND: Brennan’s rodent paw incision model has been extensively used for understanding mechanisms underlying postoperative pain in humans. However, alterations of physiological parameters like blood pressure and heart rate, or even feeding and drinking patterns after the incision have not been documented as yet. Moreover, though eicosanoids like prostaglandins and leukotrienes contribute to inflammation, tissue levels of these inflammatory mediators have never been studied. This work further investigates the antinociceptive effect of protein C after intra-wound administration. METHODS: Separate groups of Sprague–Dawley rats were used for quantitation of cyclooxygenase (COX) activity and leukotriene B4 level by enzyme-linked immunosorbent assay, as well as estimation of cardiovascular parameters and feeding and drinking behavior after paw incision. In the next part, rats were subjected to incision and 10 μg of protein C was locally administered by a micropipette. Both evoked and non-evoked pain parameters were then estimated. RESULTS: COX, particularly COX-2 activity and leukotriene B4 levels increased after incision. Hemodynamic parameters were normal. Feeding and drinking were affected on days 1 and 3, and on day 1, respectively. Protein C attenuated non-evoked pain behavior alone up to day 2. CONCLUSIONS: Based upon current observations, Brennan’s rodent paw incision model appears to exhibit a prolonged period of nociception similar to that after surgery, with minimal interference of physiological parameters. Protein C, which is likely converted to activated protein C in the wound, attenuated the guarding score, which probably represents pain at rest after surgery in humans.

Anti-neuroinflammatory Effects of 12-Dehydrogingerdione in LPS-Activated Microglia through Inhibiting Akt/IKK/NF-κB Pathway and Activating Nrf-2/HO-1 Pathway

Ginger, one of worldwide consumed dietary spice, is not only famous as food supplements, but also believed to exert a variety of remarkable pharmacological activity as herbal remedies. In this study, a ginger constituent, 12-dehydrogingerdione (DHGD) was proven that has comparable anti-inflammatory activity with positive control 6-shogaol in inhibiting LPS-induced interleukin (IL)-6, tumor necrosis factor (TNF)-α, prostaglandin (PG) E₂, nitric oxide (NO), inducible NO synthase (iNOS) and cyclooxygenase (COX)-2, without interfering with COX-1 in cultured microglial cells. Subsequent mechanistic studies indicate that 12-DHGD may inhibit neuro-inflammation through suppressing the LPS-activated Akt/IKK/NF-κB pathway. Furthermore, 12-DHGD markedly promoted the activation of NF-E2-related factor (Nrf)-2 and heme oxygenase (HO)-1, and we demonstrated that the involvement of HO-1 on the production of pro-inflammatory mediators such as NO and TNF-α by using a HO-1 inhibitor, Zinc protoporphyrin (Znpp). These results indicate that 12-DHGD may protect against neuro-inflammation by inhibiting Akt/IKK/IκB/NF-κB pathway and promoting Nrf-2/HO-1 pathway.

Periapical bone response to bacterial lipopolysaccharide is shifted upon cyclooxygenase blockage

Abstract Objectives: Infection, inflammation and bone resorption are closely related events in apical periodontitis development. Therefore, we sought to investigate the role of cyclooxygenase (COX) in osteoclastogenesis and bone metabolism signaling in periapical bone tissue after bacterial lipopolysaccharide (LPS) inoculation into root canals. Methodology: Seventy two C57BL/6 mice had the root canals of the first molars inoculated with a solution containing LPS from E. coli (1.0 mg/mL) and received selective (celecoxib) or non-selective (indomethacin) COX-2 inhibitor. After 7, 14, 21 and 28 days the animals were euthanized and the tissues removed for total RNA extraction. Evaluation of gene expression was performed by qRT-PCR. Statistical analysis was performed using analysis of variance (ANOVA) followed by post-tests (α=0.05). Results: LPS induced expression of mRNA for COX-2 (Ptgs2) and PGE2 receptors (Ptger1, Ptger3 and Ptger4), indicating that cyclooxygenase is involved in periapical response to LPS. A signaling that favours bone resorption was observed because Tnfsf11 (RANKL), Vegfa, Ctsk, Mmp9, Cd36, Icam, Vcam1, Nfkb1 and Sox9 were upregulated in response to LPS. Indomethacin and celecoxib differentially modulated expression of osteoclastogenic and other bone metabolism genes: celecoxib downregulated Igf1r, Ctsk, Mmp9, Cd36, Icam1, Nfkb1, Smad3, Sox9, Csf3, Vcam1 and Itga3 whereas indomethacin inhibited Tgfbr1, Igf1r, Ctsk, Mmp9, Sox9, Cd36 and Icam1. Conclusions: We demonstrated that gene expression for COX-2 and PGE2 receptors was upregulated after LPS inoculation into the root canals. Additionally, early administration of indomethacin and celecoxib (NSAIDs) inhibited osteoclastogenic signaling. The relevance of the cyclooxygenase pathway in apical periodontitis was shown by a wide modulation in the expression of genes involved in both bone catabolism and anabolism.

rBMSCs/ITGA5B1 Promotes Human Vascular Smooth Muscle Cell Differentiation via Enhancing Nitric Oxide Production

BACKGROUND AND OBJECTIVES: Previous studies have shown that integrins alpha5beta1 (ITGA5B1) gene-modified rat bone marrow mesenchymal stem cells (rBMSCs) could prevent cell anoikis and increase the nitric oxide (NO) production. Here we examined the capability of rBMSCs/ITGA5B1 on the phenotype modulation of Human Pulmonary Artery Smooth Muscle Cell (HPASMC) in vitro. METHODS AND RESULTS: The synthetic (dedifferentiated) phenotype of HPASMC was induced by monocrotaline (MCT, 1μM) for 24 h and then co-cultured with rBMSCs/ITGA5B1 in a transwell culture system. The activation of NO/cGMP (nitric oxide/Guanosine-3′, 5′-cyclic monophosphate) signaling was investigated in HPASMC. The changes of pro-inflammatory factors, oxidative stress, vasodilator, vasoconstrictor, contractile and synthetic genes, and the morphological changes of HPASMC were investigated. The results of this study showed that the NO/cGMP signal, endothelial nitric oxide synthase (eNOS) expression, the expression of the vasoprotective genes heme oxygenase-1 (HMOX1) and prostaglandin-endoperoxide synthase 2 (PTGS2) were increased, but the expression of transforming growth factor-β1 (TGF-β1), CCAAT/enhancer-binding proteins delta (Cebpd), Krüppel-like factor 4 (KLF4), and activating transcription factor 4 (ATF4) were reduced in MCT treated HPASMC co-cultured with rBMSCs/ITGA5B1. The synthetic smooth muscle cells (SMCs) phenotype markers thrombospondin-1, epiregulin and the vasoconstrictor endothelin (ET)-1, thromboxane A2 receptor (TbxA2R) were down-regulated, whereas the contractile SMCs phenotype marker transgelin expression was up-regulated by rBMSCs/ITGA5B1. Furthermore, rBMSCs/ITGA5B1 promoted the morphological restoration from synthetic (dedifferentiation) to contractile (differentiation) phenotype in MCT treated HPASMC. CONCLUSIONS: rBMSCs/ITGA5B1 could inhibit inflammation and oxidative stress related genes to promote the HPASMC cell differentiation by activation NO/cGMP signal.

Strategies for the safe use of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used in various clinical situations, with excellent analgesic, anti-pyretic and anti-inflammatory effects. In addition to gastrointestinal bleeding, which was the first adverse effect to be reported, myriad adverse effects from the digestive system, cardiovascular system, renal system and hematology have been also reported. In early 2000s, a few new cyclooxygenase (COX)-2 selective inhibitors were developed with the expectation of better gastrointestinal safety profile, most of them were withdrawn from the market due to various adverse effects, and interest in safety of NSAIDs has been increased again. Over the past two decades, research on the safety and adverse effects of NSAIDs has accumulated. In brief, celecoxib is associated with fewer gastrointestinal adverse events compared to non-selective NSAIDs. In patients receiving aspirin, the use of non-selective NSAIDs should be avoided, and if an anti-inflammatory drug is required, a COX-2 selective inhibitor should be considered. Celecoxib has been shown to have similar or better safety profile than other non-selective COX inhibitors. Additionally, the new COX-2 selective inhibitors of etorixocib and polmacoxib have been approved. Many factors should be considered when prescribing NSAIDs, as the safety profile of indivisual NSAIDs vary, and NSAIDs have a high risk of duplicate prescription because of the variety of indications and over-the-counter products. Physicians should comprehend the updated guidelines and the results of new clinical studies, and the risk factors for each individual patient should also be reviewed. Physicians should therefore contemplate new prescription strategies.

Estragole Exhibits Anti-inflammatory Activity with the Regulation of NF-κB and Nrf-2 Signaling Pathways in LPS-induced RAW 264.7 cells

Estragole is a naturally occurring phenylpropanoid obtained from essential oils found in a broad diversity of plants. Although the phenylpropanoids show many biological activities, clear regulation of the inflammatory signaling pathways has not yet been determined. Here, we scrutinized the anti-inflammatory effect of estragole. The anti-inflammatory effect of estragole was determined through the inhibitory mechanisms of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), nuclear factor kappa B (NF-κB), and mitogen-activated protein kinases (MAPK) pathways and the activation of nuclear factor erythroid 2-related factor 2 (Nrf-2)/heme oxygenase (HO)-1 pathways in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Estragole significantly inhibited NO production, iNOS and COX-2 expression as well as LPS-induced NF-κB and MAPK activation. Furthermore, estragole suppressed LPS-induced intracellular ROS production but up-regulated the stress response gene HO-1 via the activation of transcription factor Nrf-2. These findings demonstrate that estragole inhibits the LPS-induced expression of inflammatory mediators via the down-regulation of iNOS, COX-2, NF-κB, and MAPK pathways, as well as the up-regulation of the Nrf-2/HO-1 pathway, indicating that this phenylpropanoid has potential therapeutic and preventive applications in various inflammatory diseases.

Pulegone Exhibits Anti-inflammatory Activities through the Regulation of NF-κB and Nrf-2 Signaling Pathways in LPS-stimulated RAW 264.7 cells

Pulegone is a naturally occurring organic compound obtained from essential oils from a variety of plants. The aim of this study was to investigate the anti-inflammatory effects through the inhibitory mechanism of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), nuclear factor kappa B (NF-κB), mitogen-activated protein kinases (MAPK) pathways and the activation of nuclear factor erythroid 2-related factor 2 (Nrf2)/ heme oxygenase (HO)-1 pathways in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Results revealed that pulegone significantly inhibited NO production as well as iNOS and COX-2 expressions. Meanwhile, western blot analysis showed that pulegone down-regulated LPS-induced NF-κB and MAPKs activation in RAW 264.7 cells. Furthermore, the selected compound suppressed LPS-induced intracellular ROS production in RAW 264.7 cells, while the expression of stress response gene, HO-1, and its transcriptional activator, Nrf-2 was upregulated upon pulegone treatment. Taking together, these findings provided that pulegone inhibited the LPS-induced expression of inflammatory mediators via the down-regulation iNOS, COX-2, NF-κB, and MAPKs signaling pathways as well as up-regulation of Nrf-2/HO-1 indicating that pulegone has a potential therapeutic and preventive application in various inflammatory diseases.

From Gut to Brain: Alteration in Inflammation Markers in the Brain of Dextran Sodium Sulfate-induced Colitis Model Mice

OBJECTIVE: Neuropsychiatric manifestations like depression and cognitive dysfunction commonly occur in inflammatory bowel disease (IBD). In the context of the brain-gut axis model, colitis can lead to alteration of brain function in a bottom-up manner. Here, the changes in the response of the hypothalamic-pituitary-adrenal axis and inflammation-related markers in the brain in colitis were studied. METHODS: Dextran sodium sulfate (DSS) was used to generate a mouse model of colitis. Mice were treated with DSS for 3 or 7 days and sacrificed. We analyzed the gene expression of brain-derived neurotrophic factor (BDNF), cyclo-oxygenase 2 (COX-2), and glial fibrillary acidic protein (GFAP), and the expression of GFAP, in the hippocampus, hypothalamus, and amygdala. Additionally, the levels of C-reactive protein (CRP) and serum cortisol/corticosterone were measured. RESULTS: Alteration of inflammatory-related markers varied depending on the brain region and exposure time. In the hippocampus, COX-2 mRNA, GFAP mRNA, and GFAP expression were upregulated during exposure to DSS. However, in the hypothalamus, COX-2 mRNA was upregulated only 3 days after treatment. In the amygdala, BDNF and COX-2 mRNAs were downregulated. CRP and corticosterone expression increased with DSS treatment at day 7. CONCLUSION: IBD could lead to neuroinflammation in a bottom-up manner, and this effect varied according to brain region. Stress-related hormones and serum inflammatory markers, such as CRP, were upregulated from the third day of DSS treatment. Therefore, early and active intervention is required to prevent psychological and behavioral changes caused by IBD, and region-specific studies can help understand the precise mechanisms by which IBD affects the brain.

A New Medical Therapy for Axial Spondyloarthritis / 대한내과학회지

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been the first choice of treatment for axial spondyloarthritis (axSpA); cyclooxygenase (COX)-2 inhibitors reduce both inflammation and bone formation. When NSAID treatment fails, tumor necrosis factor inhibitors (TNFis) can be used to treat active axSpA, but, presently, TNFis cannot completely prevent radiographic progression. Theoretically, as TNF is a strong pro-inflammatory cytokine triggering bone resorption, TNFis should stimulate bone formation. Recently, it was discovered that the IL-23/-17 axis is associated with enthesitis development and bone formation in a mouse model. The anti-IL-23 monoclonal antibody ustekinumab has been approved as treatment for moderate-to-severe plaque psoriasis and psoriatic arthritis. However, in axSpA patients, ustekinumab effectiveness was low and a phase 3 clinical trial was terminated. The anti-IL-17A monoclonal antibody secukinumab has been approved as treatment for moderate-to-severe plaque psoriasis, psoriatic arthritis, and ankylosing spondylitis. In a 3-year extension of the MEASURE 1 observational study, the mean change in modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) from baseline to week 104 was 0.30 ± 2.53 among patients with evaluable X-rays originally randomized to secukinumab (n = 168). Such patients exhibited less radiographic progression compared to other TNFi studies. Several new drugs are in clinical trials exploring their effects on axSpA; these include ixekizumab (an anti-IL-17A monoclonal antibody), brodalumab (an anti-IL-17 receptor monoclonal antibody), and the Janus kinase (JAK) inhibitors tofacitinib and upadacitinib. The IL-23/-17 axis is important in terms of axSpA inflammation and bone formation. However, to date, no drug has completely prevented radiographic progression in axSpA patients.

Eicosanoids and cancer

Eicosanoids are 20-carbon bioactive lipids derived from the metabolism of polyunsaturated fatty acids, which can modulate various biological processes including cell proliferation, adhesion and migration, angiogenesis, vascular permeability and inflammatory responses. In recent years, studies have shown the importance of eicosanoids in the control of physiological and pathological processes associated with several diseases, including cancer. The polyunsaturated fatty acid predominantly metabolized to generate 2-series eicosanoids is arachidonic acid, which is the major n-6 polyunsaturated fatty acid found in animal fat and in the occidental diet. The three main pathways responsible for metabolizing arachidonic acid and other polyunsaturated fatty acids to generate eicosanoids are the cyclooxygenase, lipoxygenase and P450 epoxygenase pathways. Inflammation plays a decisive role in various stages of tumor development including initiation, promotion, invasion and metastasis. This review will focus on studies that have investigated the role of prostanoids and lipoxygenase-derived eicosanoids in the development and progression of different tumors, highlighting the findings that may provide insights into how these eicosanoids can influence cell proliferation, cell migration and the inflammatory process. A better understanding of the complex role played by eicosanoids in both tumor cells and the tumor microenvironment may provide new markers for diagnostic and prognostic purposes and identify new therapeutic strategies in cancer treatment.

The role of potassium channels in the endothelial dysfunction induced by periodontitis

Abstract Objective: Periodontitis is associated with endothelial dysfunction, which is clinically characterized by a reduction in endothelium-dependent relaxation. However, we have previously shown that impairment in endothelium-dependent relaxation is transient. Therefore, we evaluated which mediators are involved in endothelium-dependent relaxation recovery. Material and methods: Rats were subjected to ligature-induced experimental periodontitis. Twenty-one days after the procedure, the animals were prepared for blood pressure recording, and the responses to acetylcholine or sodium nitroprusside were obtained before and 30 minutes after injection of a nitric oxide synthase inhibitor (L-NAME), cyclooxygenase inhibitor (Indomethacin, SC-550 and NS- 398), or calcium-dependent potassium channel blockers (apamin plus TRAM- 34). The maxilla and mandible were removed for bone loss analysis. Blood and gingivae were obtained for C-reactive protein (CRP) and myeloperoxidase (MPO) measurement, respectively. Results: Experimental periodontitis induces bone loss and an increase in the gingival MPO and plasmatic CRP. Periodontitis also reduced endothelium-dependent vasodilation, a hallmark of endothelial dysfunction, 14 days after the procedure. However, the response was restored at day 21. We found that endothelium-dependent vasodilation at day 21 in ligature animals was mediated, at least in part, by the activation of endothelial calcium-activated potassium channels. Conclusions: Periodontitis induces impairment in endothelial-dependent relaxation; this impairment recovers, even in the presence of periodontitis. The recovery is mediated by the activation of endothelial calcium-activated potassium channels in ligature animals. Although important for maintenance of vascular homeostasis, this effect could mask the lack of NO, which has other beneficial properties.

Nonsteroidal anti-inflammatory drug hypersensitivity in the Asia-Pacific

Nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity reactions (HSRs) are often nonimmunologically mediated reactions which present with immediate HSR type manifestations. These are mediated by cyclooxygenase inhibition resulting in shunting towards the excessive production of leukotrienes. Important disease associations include asthma, nasal polyposis, and chronic spontaneous urticaria, especially among adults. The European Network on Drug Allergy/Global Allergy and Asthma European Network 2013 classification of NSAID HSR comprises nonselective HSR i.e., NSAID exacerbated respiratory disease (NERD), NSAIDs exacerbated cutaneous disease (NECD), NSAIDs induced urticarial-angioedema (NIUA); and selective (allergic) HSR i.e., single NSAID induced urticaria/angioedema or anaphylaxis, NSAIDs-induced delayed HSR. Much of the literature on genetic associations with NSAID HSR originate from Korea and Japan; where genetic polymorphisms have been described in genes involved in arachidonic acid metabolism, basophil/mast cell/eosinophil activation, various inflammatory mediators/cytokines, and different HLA genotypes. The Asian phenotype for NSAID HSR appears to be predominantly NIUA with overlapping features in some adults and children. NECD also appears to be more common than NERD, although both are not common in the Asian paediatric population. Between adults and children, children seem to be more atopic, although over time when these children grow up, it is likely that the prevalence of atopic adults with NSAID HSR will increase. Low-dose aspirin desensitization has been shown to be effective in the treatment of coronary artery disease, especially following percutaneous coronary intervention.

Acetylcholine produces contractions mediated by the cyclooxygenase pathway in arterial vessels in the Chilean frog (Calyptocephalella gayi) / Acetilcolina produz contrações mediadas pela via da ciclooxigenase em vasos arteriais da rã chileno (Calyptocephalella gayi)

Abstract Previous studies performed in marine fish (I. conceptionis and G. laevifrons) showed that indomethacin blocked arterial contraction mediated by acetylcholine (ACh). The objective of this study was to determine if contraction induced by acetylcholine is mediated by the cyclooxygenase pathway in several arterial vessels in the Chilean frog Calyptocephalella gayi. Arteries from the pulmonary (PA), dorsal (DA), mesenteric (MA) and iliac (IA) regions were dissected from 6 adult specimens, and isometric tension studies were done using dose response curves (DRC) for ACh (10-13 to 10-3 M) in presence of a muscarinic antagonist (Atropine 10-5 M) and an unspecific inhibitor of cyclooxygenases (Indomethacin, 10-5M). All the studied arteries exhibited vasoconstriction mediated by ACh. This vasoconstriction was abolished in the presence of atropine in DA, MA and IA and attenuated in PA. Indomethacin abolished the vasoconstriction in MA and attenuated the response in PA, DA and IA. Similar to marine fish, C. gayi have an ACh-mediated vasoconstrictor pattern regulated by muscarinic receptors that activate a cyclooxygenase contraction pathway. These results suggest that the maintenance in vasoconstrictor mechanisms mediated by ACh→COX →vasoconstriction is conserved from fish to frogs.

Resumo Estudos feitos em peixes marinhos (I. conceptionis e G. laevifrons) têm demostrado que a indometacina bloqueia a contração arterial mediada por acetilcolina (ACh). O objetivo do presente estudo foi avaliar o efeito da via da ciclooxigenase na contração induzida por ACh em vasos arteriais da rã chilena Calyptocephalella gayi. Foram dissecadas regiões das artérias pulmonares (PA), dorsal (DA), mesentérica (MA) e ilíaca (IA) de seis espécimes adultos e realizados estudos de tensão isométrica utilizando curvas dose-resposta (CDR) de ACh (10-13 a 10-3 M) na presença de um antagonista muscarínico (atropina, 10-5 M) e um inibidor das ciclooxigenases (indometacina, 10-5 M). Todas as artérias evidenciaram uma resposta vasoconstritora mediada por ACh. Esta resposta vasoconstrictora foi suprimida na presença de atropina nas artérias DA, MA, IA e atenuada na PA. A indometacina suprimiu a vasoconstrição na artéria MA e atenuou a resposta nas artérias PA, DA e IA. Tal como os peixes marinhos, a C. gayi tem um padrão de vasoconstrição mediado por Ach que é regulado pelos receptores muscarínicos e pela ciclooxigenase. Estes resultados sugerem a conservação dos mecanismos vasoconstrictores mediados por ACh→COX em peixes e rãs.