The metabolic effects of inhibitors of 5-lipoxygenase and of cyclooxygenase 1 and 2 are an advancement in the efficacy and safety of anti-inflammatory therapy

Clinical Study of Aspirin and Zileuton on Biomarkers of Tobacco-Related Carcinogenesis in Current Smokers

The chemopreventive effect of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) on lung cancer risk is supported by epidemiologic and preclinical studies. Zileuton, a 5-lipoxygenase inhibitor, has additive activity with NSAIDs against tobacco carcinogenesis in preclinical models. We hypothesized that cyclooxygenase plus 5-lipoxygenase inhibition would be more effective than a placebo in modulating the nasal epithelium gene signatures of tobacco exposure and lung cancer. We conducted a randomized, double-blinded study of low-dose aspirin plus zileuton vs. double placebo in current smokers to compare the modulating effects on nasal gene expression and arachidonic acid metabolism. In total, 63 participants took aspirin 81 mg daily plus zileuton (Zyflo CR) 600 mg BID or the placebo for 12 weeks. Nasal brushes from the baseline, end-of-intervention, and one-week post intervention were profiled via microarray. Aspirin plus zilueton had minimal effects on the modulation of the nasal or bronchial gene expression signatures of smoking, lung cancer, and COPD but favorably modulated a bronchial gene expression signature of squamous dysplasia. Aspirin plus zileuton suppressed urinary leukotriene but not prostaglandin E2, suggesting shunting through the cyclooxygenase pathway when combined with 5-lipoxygenase inhibition. Continued investigation of leukotriene inhibitors is needed to confirm these findings, understand the long-term effects on the airway epithelium, and identify the safest, optimally dosed agents.

Novel Applications of NSAIDs: Insight and Future Perspectives in Cardiovascular, Neurodegenerative, Diabetes and Cancer Disease Therapy

Once it became clear that inflammation takes place in the modulation of different degenerative disease including neurodegenerative, cardiovascular, diabetes and cancer the researchers has started intensive programs evaluating potential role of non-steroidal anti-inflammatory drugs (NSAIDs) in the prevention or therapy of these diseases. This review discusses the novel mechanism of action of NSAIDs and its potential use in the pharmacotherapy of neurodegenerative, cardiovascular, diabetes and cancer diseases. Many different molecular and cellular factors which are not yet fully understood play an important role in the pathogenesis of inflammation, axonal damage, demyelination, atherosclerosis, carcinogenesis thus further NSAID studies for a new potential indications based on precise pharmacotherapy model are warranted since NSAIDs are a heterogeneous group of medicines with relative different pharmacokinetics and pharmacodynamics profiles. Hopefully the new data from studies will fill in the gap between experimental and clinical results and translate our knowledge into successful disease therapy.

Metabolism pathways of arachidonic acids: mechanisms and potential therapeutic targets

The arachidonic acid (AA) pathway plays a key role in cardiovascular biology, carcinogenesis, and many inflammatory diseases, such as asthma, arthritis, etc. Esterified AA on the inner surface of the cell membrane is hydrolyzed to its free form by phospholipase A2 (PLA2), which is in turn further metabolized by cyclooxygenases (COXs) and lipoxygenases (LOXs) and cytochrome P450 (CYP) enzymes to a spectrum of bioactive mediators that includes prostanoids, leukotrienes (LTs), epoxyeicosatrienoic acids (EETs), dihydroxyeicosatetraenoic acid (diHETEs), eicosatetraenoic acids (ETEs), and lipoxins (LXs). Many of the latter mediators are considered to be novel preventive and therapeutic targets for cardiovascular diseases (CVD), cancers, and inflammatory diseases. This review sets out to summarize the physiological and pathophysiological importance of the AA metabolizing pathways and outline the molecular mechanisms underlying the actions of AA related to its three main metabolic pathways in CVD and cancer progression will provide valuable insight for developing new therapeutic drugs for CVD and anti-cancer agents such as inhibitors of EETs or 2J2. Thus, we herein present a synopsis of AA metabolism in human health, cardiovascular and cancer biology, and the signaling pathways involved in these processes. To explore the role of the AA metabolism and potential therapies, we also introduce the current newly clinical studies targeting AA metabolisms in the different disease conditions.

In Silico Screening for Anti-inflammatory Bioactive Molecules from Ayurvedic Decoction, Balaguluchyadi kashayam

BACKGROUND

Balaguluchyadi kashayam, a polyherbal Ayurvedic decoction prepared from Sidacordifolia L., Tinospora cordifolia (Willd.) Miers, and Cedrusdeodara (Roxb. ex D.Don) G.Don, is used in Ayurveda for the treatment of chronic inflammatory conditions. Although this herbal decoction has been used for a long period for treating chronic inflammatory conditions, the mechanism of action of the decoction in reducing inflammatory conditions associated with chronic inflammation has not been clearly understood. Mass spectroscopy-based identification of bioactive molecules present in the decoction and its interaction with enzymes/proteins involved in the pathogenesis of chronic inflammation has been carried and reported in this study.

INTRODUCTION

Polyherbalism is one of the major principles of Ayurveda. Various phytoconstituents with different activities in the polyherbal decoction act on multi targets of a wide range of diseases. Balaguluchyadi kashayam is a polyherbal decoction prescribed for chronic inflammatory etiologies and the present study aims to evaluate the binding potential of the compounds, identified from Balaguluchyadi kashayam to enzymes/proteins involved in the development and progression of chronic inflammation.

METHODS

The bioactive compounds present in the Balaguluchyadi Kashayam fractions were extracted by preparative HPLC and identified using UPLC MS Q-TOF. The physicochemical characteristics and ADMET properties of the compounds were calculated using Mol soft, Swiss ADME and OSIRIS data warrior software. Then the binding interactions between the molecules and the proinflammatory mediators such as 5 Lipoxygenase, Cyclooxygenase 2, Tumor necrosis factoralpha convertase enzyme (TACE) and Caspase 1 were determined using molecular docking software Auto Dock 4.0 (http://autodock.scripps.edu/downloads).

RESULTS

The identified bioactive molecules in the decoction showed a good binding affinity towards the enzymes/proteins involved in the development and progression of chronic inflammation compared to the binding affinity of known inhibitors/drugs to the respective enzymes/proteins.

CONCLUSION

The bioactive molecules identified in Balaguluchyadi Kashayam could be developed as potential therapeutic molecules against enzymes/proteins involved in the development and progression of chronic inflammation.

Arachidonic Acid Metabolites in Cardiovascular and Metabolic Diseases

Lipid and immune pathways are crucial in the pathophysiology of metabolic and cardiovascular disease. Arachidonic acid (AA) and its derivatives link nutrient metabolism to immunity and inflammation, thus holding a key role in the emergence and progression of frequent diseases such as obesity, diabetes, non-alcoholic fatty liver disease, and cardiovascular disease. We herein present a synopsis of AA metabolism in human health, tissue homeostasis, and immunity, and explore the role of the AA metabolome in diverse pathophysiological conditions and diseases.

Evaluation of anti-inflammatory and immunomodulatory effects of Premna integrifolia extracts and assay-guided isolation of a COX-2/5-LOX dual inhibitor

Premna integrifolia (Agnimantha brihat) is a traditional medicinal plant with a prominent place in Ayurveda, Siddha and Unani systems of medicine. In this study we have evaluated the anti-inflammatory and immunomodulatory properties of the Premna integrifolia root extracts employing cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) enzyme-based assays, lymphocyte proliferation assay, pro-and anti-inflammatory cytokines measurement. Petroleum ether extract (PEE) of Premna integrifolia showed potent inhibition of COX-2 and 5-LOX with IC₅₀ values of 6.15 μg/mL and 11.33 μg/mL respectively. In in vitro studies on RAW 264.7 cell line, PEE showed inhibition in the formation of nitric oxide (NO), pro-inflammatory cytokines (IL-1β, IL-6), prostaglandin E₂ (PGE₂) production, induction of anti-inflammatory cytokine (IL-2) and down-regulation of expression of COX-2, 5-LOX, TNF-α, IL-1β and iNOS. PEE also significantly reduced carrageenan-induced paw edema in mouse model of inflammation. Further, attempts in isolating the active principle(s) involved in these anti-inflammatory effects of PEE by separation on RP-HPLC resulted in the isolation of four active peaks, H1, H2, H3 and H5, inhibiting COX-1, COX-2 and 5-LOX, out of which H3 was identified as 6- hydroxy salvinolone (6-HS). Present findings reveal that PEE of roots of Premna integrifolia exhibits potent anti-inflammatory and immunomodulatory activities, which could form a potential source for development of anti-inflammatory drugs. 6-HS, a COX-2/5-LOX dual inhibitor along with other lead molecules isolated from PEE of Premna integrifolia may form lead molecules for the development of COX-LOX dual inhibitors.

A Metabolomic Approach to Target Compounds from the Asteraceae Family for Dual COX and LOX Inhibition

The application of metabolomics in phytochemical analysis is an innovative strategy for targeting active compounds from a complex plant extract. Species of the Asteraceae family are well-known to exhibit potent anti-inflammatory (AI) activity. Dual inhibition of the enzymes COX-1 and 5-LOX is essential for the treatment of several inflammatory diseases, but there is not much investigation reported in the literature for natural products. In this study, 57 leaf extracts (EtOH-H₂O 7:3, v/v) from different genera and species of the Asteraceae family were tested against COX-1 and 5-LOX while HPLC-ESI-HRMS analysis of the extracts indicated high diversity in their chemical compositions. Using O2PLS-DA (R² > 0.92; VIP > 1 and positive Y-correlation values), dual inhibition potential of low-abundance metabolites was determined. The O2PLS-DA results exhibited good validation values (cross-validation = Q² > 0.7 and external validation = P² > 0.6) with 0% of false positive predictions. The metabolomic approach determined biomarkers for the required biological activity and detected active compounds in the extracts displaying unique mechanisms of action. In addition, the PCA data also gave insights on the chemotaxonomy of the family Asteraceae across its diverse range of genera and tribes.

Comparison of selective and non selective cyclo-oxygenase 2 inhibitors in experimental colitis exacerbation: role of leukotriene B4 and superoxide dismutase

CONTEXT

Nonsteroidal anti-inflammatory drugs are considered one of the most important causes of reactivation of inflammatory bowel disease. With regard to selective cyclo-oxygenase 2 inhibitors, the results are controversial in experimental colitis as well as in human studies.

OBJECTIVES

The aim this study is to compare nonsteroidal anti-inflammatory drugs effects, selective and non selective cyclo-oxygenase 2 inhibitors, in experimental colitis and contribute to the understanding of the mechanisms which nonsteroidal anti-inflammatory drugs provoke colitis exacerbation.

METHODS

Six groups of rats: without colitis, with colitis, and colitis treated with celecoxib, ketoprofen, indometacin or diclofenac. Survival rates, hemoglobin, plasmatic albumin, colonic tissue of interleukin-1ß, interleukin-6, tumor necrosis factor alpha, prostaglandin E2, catalase, superoxide dismutase, thiobarbituric acid-reactive substances, chemiluminescence induced by tert-butil hydroperoxides, and tissue and plasmatic leukotriene B4 were determined.

RESULTS

The groups treated with diclofenac or indometacin presented lower survival rates, hemoglobin and albumin, higher tissue and plasmatic leukotriene B4 and tissue superoxide dismutase than the group treated with celecoxib. Ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib, concerning to survival rate and albumin. The groups without colitis, with colitis and with colitis treated with celecoxib showed leukotriene B4 and superoxide dismutase lower levels than the groups treated with nonselective cyclo-oxygenase 2 inhibitors.

CONCLUSIONS

Diclofenac and indometacin presented the highest degree of induced colitis exacerbation with nonsteroidal anti-inflammatory drugs, celecoxib did not show colitis exacerbation, and ketoprofen presented an intermediary behavior between diclofenac/indometacin and celecoxib. These results suggest that leukotriene B4 and superoxide dismutase can be involved in the exacerbation of experimental colitis by nonselective nonsteroidal anti-inflammatory drugs.

Naproxen induces type X collagen expression in human bone-marrow-derived mesenchymal stem cells through the upregulation of 5-lipoxygenase

Several studies have shown that type X collagen (COL X), a marker of late-stage chondrocyte hypertrophy, is expressed in mesenchymal stem cells (MSCs) from osteoarthritis (OA) patients. We recently found that Naproxen, but not other nonsteroidal anti-inflammatory drugs (NSAIDs) (Ibuprofen, Celebrex, Diclofenac), can induce type X collagen gene (COL10A1) expression in bone-marrow-derived MSCs from healthy and OA donors. In this study we determined the effect of Naproxen on COL X protein expression and investigated the intracellular signaling pathways that mediate Naproxen-induced COL10A1 expression in normal and OA hMSCs. MSCs of OA patients were isolated from aspirates from the intramedullary canal of donors (50-80 years of age) undergoing hip replacement surgery for OA and were treated with or without Naproxen (100 μg/mL). Protein expression and phosphorylation were determined by immunoblotting using specific antibodies (COL X, p38 mitogen-activated protein kinase [p38], phosphorylated-p38, c-Jun N-terminal kinase [JNK], phosphorylated-JNK, extracellular signal-regulated kinase [ERK], and phosphorylated-ERK). Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to determine the expression of COL10A1 and Runt-related transcription factor 2 gene (Runx2). Our results show that Naproxen significantly stimulated COL X protein expression after 72 h of exposure both in normal and OA hMSCs. The basal phosphorylation of mitogen-activated protein kinases (MAPKs) (ERK, JNK, and p38) in OA hMSCs was significantly higher than in normal. Naproxen significantly increased the MAPK phosphorylation in normal and OA hMSCs. NSAID cellular effects include cyclooxygenase, 5-lipoxygenase, and p38 MAPK signaling pathways. To investigate the involvement of these pathways in the Naproxen-induced COL10A1 expression, we incubated normal and OA hMSCs with Naproxen with and without inhibitors of ERK (U0126), JNK (BI-78D3), p38 (SB203580), and 5-lipoxygenase (MK-886). Our results showed that increased basal COL10A1 expression in OA hMSCs was significantly suppressed in the presence of JNK and p38 inhibitors, whereas Naproxen-induced COL10A1 expression was suppressed by 5-lipoxygenase inhibitor. This study shows that Naproxen induces COL X both at transcriptional and translational levels in normal and OA hMSCs. Elevated basal COL10A1 expression in OA hMSCs is probably through the activation of MAPK pathway and Naproxen-induced COL10A1 expression is through the increased 5-lipoxygenase signaling.

Cyclooxygenase-2 and 5-lipoxygenase in dogs with chronic enteropathies

Background

Cyclooxygenase‐2 (COX‐2) is a key enzyme in the synthesis of pro‐inflammatory prostaglandins and 5‐lipoxygenase (5‐LO) is the major source of leukotrienes. Their role in IBD has been demonstrated in humans and animal models, but not in dogs with chronic enteropathies (CCE).

Hypothesis

COX‐2 and 5‐LO are upregulated in dogs with CCE.

Animals

Fifteen healthy control dogs (HCD), 10 dogs with inflammatory bowel disease (IBD), and 15 dogs with food‐responsive diarrhea (FRD).

Methods

Prospective study. mRNA expression of COX‐2, 5‐LO, IL‐1b, IL‐4, IL‐6, TNF, IL‐10 and TFG‐β was evaluated by quantitative real‐time RT‐PCR in duodenal and colonic biopsies before and after treatment.

Results

COX‐2 expression in the colon was significantly higher in IBD and FRD before and after treatment (all P < .01). IL‐1b was higher in FRD in the duodenum after treatment (P = .021). TGF‐β expression was significantly higher in the duodenum of HCD compared to FRD/IBD before treatment (both P < .001) and IBD after treatment (P = .012). There were no significant differences among groups and within groups before and after treatment for IL‐4, IL‐6, TNF, and IL‐10. There was a significant correlation between COX‐2 and IL‐1b in duodenum and colon before treatment in FRD and IBD, whereas 5‐LO correlated better with IL‐6 and TNF. IL‐10 and TGF‐β usually were correlated.

Conclusions and Clinical Importance

COX‐2 is upregulated in IBD and FRD, whereas IL‐1b and TGF‐β seem to be important pro‐ and anti‐inflammatory cytokines, respectively. The use of dual COX/5‐LO inhibitors could be an interesting alternative in the treatment of CCE.

The Medicinal Timber Canarium patentinervium Miq. (Burseraceae Kunth.) Is an Anti-Inflammatory Bioresource of Dual Inhibitors of Cyclooxygenase (COX) and 5-Lipoxygenase (5-LOX)

The barks and leaves extracts of Canarium patentinervium Miq. (Burseraceae Kunth.) were investigated for cyclooxygenase (COX) and 5-lipoxygenase (LOX) inhibition via in vitro models. The corresponding antioxidative power of the plant extract was also tested via nonenzyme and enzyme in vitro assays. The ethanolic extract of leaves inhibited the enzymatic activity of 5-LOX, COX-1, and COX-2 with IC₅₀ equal to 49.66 ± 0.02 μg/mL, 0.60 ± 0.01 μg/mL, and 1.07 ± 0.01 μg/mL, respectively, with selective COX-2 activity noted in ethanolic extract of barks with COX-1/COX-2 ratio of 1.22. The ethanol extract of barks confronted oxidation in the ABTS, DPPH, and FRAP assay with EC₅₀ values equal to 0.93 ± 0.01 μg/mL, 2.33 ± 0.02 μg/mL, and 67.00 ± 0.32 μg/mL, respectively, while the ethanol extract of leaves confronted oxidation in β-carotene bleaching assay and superoxide dismutase (SOD) assay with EC₅₀ value of 6.04 ± 0.02 μg/mL and IC₅₀ value of 3.05 ± 0.01 μg/mL. The ethanol extract acts as a dual inhibitor of LOX and COX enzymes with potent antioxidant capacity. The clinical significance of these data is quite clear that they support a role for Canarium patentinervium Miq. (Burseraceae Kunth.) as a source of lead compounds in the management of inflammatory diseases.

Current perspectives in NSAID-induced gastropathy

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most highly prescribed drugs in the world. Their analgesic, anti-inflammatory, and antipyretic actions may be beneficial; however, they are associated with severe side effects including gastrointestinal injury and peptic ulceration. Though several approaches for limiting these side effects have been adopted, like the use of COX-2 specific drugs, comedication of acid suppressants like proton pump inhibitors and prostaglandin analogs, these alternatives have limitations in terms of efficacy and side effects. In this paper, the mechanism of action of NSAIDs and their critical gastrointestinal complications have been reviewed. This paper also provides the information on different preventive measures prescribed to minimize such adverse effects and analyses the new suggested strategies for development of novel drugs to maintain the anti-inflammatory functions of NSAIDs along with effective gastrointestinal protection.

Trihydroxyflavones with antioxidant and anti-inflammatory efficacy

The classical anti-inflammatory therapies are frequently ineffective and present numerous and severe side effects, especially in long term use, which requires the development of anti-inflammatory drugs with different scaffolds and mechanisms of action. Owing to the high antioxidant potential and anti-inflammatory activities already inferred for hydroxyflavones, we found it would be relevant to evaluate the anti-inflammatory potential of a series of trihydroxyflavones by testing their ability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) in cells and cell-free systems and to inhibit the proinflammatory pathways mediated by the enzymes cyclooxygenase (COX) and 5-lipoxygenase (5-LOX), in which reactive species have a proven involvement. The tested trihydroxyflavones proved to be effective inhibitors of neutrophils' oxidative burst and were shown to scavenge different ROS and RNS in cell-free systems. The most active compound in the majority of the assays was 3,3',4'-trihydroxyflavone, which was somehow expected due to the presence of the ortho-dihydroxy in the B-ring, an important structural feature in terms of free radical scavenging activity. Additionally, the studied compounds were able to inhibit the production of leukotriene B(4) by 5-LOX in activated neutrophils. 3,5,7-Trihydroxyflavone was able to inhibit both COX-1 and COX-2, which makes it a dual inhibitor of COX and 5-LOX pathways and, therefore, a promising candidate for a new therapeutic option in the treatment of inflammatory processes.

Role of lipoxins, resolvins, and other bioactive lipids in colon and pancreatic cancer

Unresolved inflammation, due to insufficient production of proresolving anti-inflammatory lipid mediators, can lead to an increased risk of tumorigenesis and tumor cell invasiveness. Various bioactive lipids, particularly those formed by cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, have been well established as therapeutic targets for many epithelial cancers. Emerging studies suggest that there is a role for anti-inflammatory bioactive lipids and their mediators during the resolution phase of inflammation. These proresolving bioactive lipids, including lipoxins (LXs) and resolvins (RVs), have potent anti-inflammatory and anti-carcinogenic properties. The molecular signaling pathways controlling generation and degradation of the proresolving mediators LXs and RVs are now being elucidated, and the component molecules may serve as new targets for regulation of inflammation and inflammation-associated cancers like colon and pancreatic cancers. This review will highlight the recent advances in our understanding of how these bioactive lipids and proresolving mediators may function with various immune cells and cytokines in inhibiting tumor cell proliferation and progression and invasiveness of colon and pancreatic cancers.

Multiple roles of dihomo-γ-linolenic acid against proliferation diseases

Considerable arguments remain regarding the diverse biological activities of polyunsaturated fatty acids (PUFA). One of the most interesting but controversial dietary approaches focused on the diverse function of dihomo-dietary γ-linolenic acid (DGLA) in anti-inflammation and anti-proliferation diseases, especially for cancers. This strategy is based on the ability of DGLA to interfere in cellular lipid metabolism and eicosanoid (cyclooxygenase and lipoxygenase) biosynthesis. Subsequently, DGLA can be further converted by inflammatory cells to 15-(S)-hydroxy-8,11,13-eicosatrienoic acid and prostaglandin E₁ (PGE₁). This is noteworthy because these compounds possess both anti-inflammatory and anti-proliferative properties. PGE1 could also induce growth inhibition and differentiation of cancer cells. Although the mechanism of DGLA has not yet been elucidated, it is significant to anticipate the antitumor potential benefits from DGLA.

Licofelone attenuates quinolinic acid induced Huntington like symptoms: possible behavioral, biochemical and cellular alterations

Cyclo-oxygenase and lipoxygenase enzymes are involved in arachidonic acid metabolism. Emerging evidence indicates that cyclo-oxygenase and lipoxygenase inhibitors prevent neurodegenerative processes and related complications. Therefore, the present study has been designed to explore the neuroprotective potential of licofelone (dual COX-2/5-LOX inhibitor) against quinolinic acid induced Huntington like symptom in rats. Intrastriatal administration of quinolinic acid significantly caused reduction in body weight and motor function (locomotor activity, rotarod performance and beam walk test), oxidative defense (as evidenced by increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidant enzymes), alteration in mitochondrial enzyme complex (I, II and IV) activities, raised TNF-α level and striatal lesion volume as compared to sham treated animals. Licofelone (2.5, 5 and 10 mg/kg) treatment significantly improved body weight, locomotor activity, rotarod performance, balance beam walk performance, oxidative defense, mitochondrial enzyme complex activities and attenuated TNF-α level and striatal lesion as compared to control (quinolinic acid). The present study highlights that licofelone attenuates behavioral, biochemical and cellular alterations against quinolinic acid induced neurotoxicity and this could be an important therapeutic avenue to ameliorate the Huntington like symptoms.

Protection from hepatic lipid accumulation and inflammation by genetic ablation of 5-lipoxygenase

Five-lipoxygenase (5-LO) has been postulated as a pathogenic factor in liver injury. Indeed, Alox5, the gene coding for 5-LO, is heavily over-expressed in experimental liver disease, in which 5-LO inhibition consistently ameliorates hepatic steatosis, inflammation and fibrosis. Herein, we report the findings in mice with targeted deletion of Alox5 as a proof of concept of the role of 5-LO in liver injury. Our findings demonstrate that ablation of Alox5 in mice confers protection against carbon tetrachloride-induced liver injury since hepatic necroinflammation, inflammatory infiltrate, hepatocyte ballooning and serum ALT levels were significantly reduced in Alox5-deficient mice. These mice also showed a lower degree of hepatic steatosis, which affected micro- and macrosteatosis to a similar extent. Moreover, microarray analysis revealed a differential profile of hepatic gene expression in Alox5-deficient mice, with a total of 117 genes differentially expressed in these animals. Functional grouping of these genes revealed that 28 (approximately 24% of total changes) were related to the category of lipid metabolism, including the lipogenic factors Lpin1, C/EBP, Fasn, Acly and Elovl6. Moreover, Ingenuity Pathway Analysis revealed lipid metabolism as the molecular/cellular function most affected by the loss of Alox5. These findings confirm at a genetic level that Alox5 plays a pathogenic role in the response of the liver to injury.

Flavocoxid, a dual inhibitor of cyclooxygenase and 5-lipoxygenase, blunts pro-inflammatory phenotype activation in endotoxin-stimulated macrophages

BACKGROUND AND PURPOSE

The flavonoids, baicalin and catechin, from Scutellaria baicalensis and Acacia catechu, respectively, have been used for various clinical applications. Flavocoxid is a mixed extract containing baicalin and catechin, and acts as a dual inhibitor of cyclooxygenase (COX) and 5-lipoxygenase (LOX) enzymes. The anti-inflammatory activity, measured by protein and gene expression of inflammatory markers, of flavocoxid in rat peritoneal macrophages stimulated with Salmonella enteritidis lipopolysaccharide (LPS) was investigated.

EXPERIMENTAL APPROACH

LPS-stimulated (1 microg.mL(-1)) peritoneal rat macrophages were co-incubated with different concentrations of flavocoxid (32-128 microg.mL(-1)) or RPMI medium for different incubation times. Inducible COX-2, 5-LOX, inducible nitric oxide synthase (iNOS) and inhibitory protein kappaB-alpha (IkappaB-alpha) levels were evaluated by Western blot analysis. Nuclear factor kappaB (NF-kappaB) binding activity was investigated by electrophoretic mobility shift assay. Tumour necrosis factor-alpha (TNF-alpha) gene and protein expression were measured by real-time polymerase chain reaction and enzyme-linked immunosorbent assay respectively. Finally, malondialdehyde (MDA) and nitrite levels in macrophage supernatants were evaluated.

KEY RESULTS

LPS stimulation induced a pro-inflammatory phenotype in rat peritoneal macrophages. Flavocoxid (128 microg.mL(-1)) significantly inhibited COX-2 (LPS = 18 +/- 2.1; flavocoxid = 3.8 +/- 0.9 integrated intensity), 5-LOX (LPS = 20 +/- 3.8; flavocoxid = 3.1 +/- 0.8 integrated intensity) and iNOS expression (LPS = 15 +/- 1.1; flavocoxid = 4.1 +/- 0.4 integrated intensity), but did not modify COX-1 expression. PGE(2) and LTB(4) levels in culture supernatants were consequently decreased. Flavocoxid also prevented the loss of IkappaB-alpha protein (LPS = 1.9 +/- 0.2; flavocoxid = 7.2 +/- 1.6 integrated intensity), blunted increased NF-kappaB binding activity (LPS = 9.2 +/- 2; flavocoxid = 2.4 +/- 0.7 integrated intensity) and the enhanced TNF-alpha mRNA levels (LPS = 8 +/- 0.9; flavocoxid = 1.9 +/- 0.8 n-fold/beta-actin) induced by LPS. Finally, flavocoxid decreased MDA, TNF and nitrite levels from LPS-stimulated macrophages.

CONCLUSION AND IMPLICATIONS

Flavocoxid might be useful as a potential anti-inflammatory agent, acting at the level of gene and protein expression.

Effects of N-acetylcysteine plus mesalamine on prostaglandin synthesis and nitric oxide generation in TNBS-induced colitis in rats

The aim of the present studies was to examine mechanisms by which the rectally administered combination of N-acetylcysteine (NAC) plus mesalamine (5-ASA) affects inducers of inflammation to promote mucosal healing and reduce tissue inflammation in chemically (trinitrobenzene sulfonic acid, TNBS) induced colitis in rats. Experimental findings demonstrate that dual therapy with NAC plus 5-ASA was superior to individual agents in reducing histological measures of colitis. NAC alone and in combination with 5-ASA suppressed COX2 gene expression and prostaglandin E(2) (PGE(2)) levels to control values. Furthermore, NAC plus 5-ASA reduced nitrate generation, an expression of inducible nitric oxide synthase (iNOS) activity, to basal levels and these results were significantly lower than those observed with either NAC or 5-ASA alone. In conclusion, these results indicate that NAC plus 5-ASA exerts therapeutic benefit, in part by countering the actions of PGE(2) and the deleterious effects of oxidative and nitrosative stress induced by TNBS colitis.

Cartilage in normal and osteoarthritis conditions

The preservation of articular cartilage depends on keeping the cartilage architecture intact. Cartilage strength and function depend on both the properties of the tissue and on their structural parameters. The main structural macromolecules are collagen and proteoglycans (aggrecan). During life, cartilage matrix turnover is mediated by a multitude of complex autocrine and paracrine anabolic and catabolic factors. These act on the chondrocytes and can lead to repair, remodeling or catabolic processes like those that occur in osteoarthritis. Osteoarthritis is characterized by degradation and loss of articular cartilage, subchondral bone remodeling, and, at the clinical stage of the disease, inflammation of the synovial membrane. The alterations in osteoarthritic cartilage are numerous and involve morphologic and metabolic changes in chondrocytes, as well as biochemical and structural alterations in the extracellular matrix macromolecules.

A medicinal extract of Scutellaria baicalensis and Acacia catechu acts as a dual inhibitor of cyclooxygenase and 5-lipoxygenase to reduce inflammation

A mixed extract containing two naturally occurring flavonoids, baicalin from Scutellaria baicalensis and catechin from Acacia catechu, was tested for cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) inhibition via enzyme, cellular, and in vivo models. The 50% inhibitory concentration for inhibition of both ovine COX-1 and COX-2 peroxidase enzyme activities was 15 microg/mL, while the mixed extract showed a value for potato 5-LOX enzyme activity of 25 microg/mL. Prostaglandin E2 generation was inhibited by the mixed extract in human osteosarcoma cells expressing COX-2, while leukotriene production was inhibited in both human cell lines, immortalized THP-1 monocyte and HT-29 colorectal adenocarcinoma. In an arachidonic acid-induced mouse ear swelling model, the extract decreased edema in a dose-dependent manner. When arachidonic acid was injected directly into the intra-articular space of mouse ankle joints, the mixed extract abated the swelling and restored function in a rotary drum walking model. These results suggest that this natural, flavonoid mixture acts via "dual inhibition" of COX and LOX enzymes to reduce production of pro-inflammatory eicosanoids and attenuate edema in an in vivo model of inflammation.

Licofelone, a dual COX/5-LOX inhibitor, induces apoptosis in HCA-7 colon cancer cells through the mitochondrial pathway independently from its ability to affect the arachidonic acid cascade

Nowadays, no data are available concerning the potential use of dual cyclooxygenase (COX)/5-lipoxygenase (LOX) inhibitors as anticancer agents in colon cancer treatment. Here, we report, for the first time, that the dual COX/5-LOX inhibitor licofelone triggers apoptosis in a dose- and time-dependent manner in HCA-7 colon cancer cells. Induction of apoptosis was related to the recruitment of the intrinsic mitochondrial apoptotic pathway, as shown by loss in mitochondrial membrane potential, cytochrome c release, caspase-9 and 3 activation and poly-(ADP-ribose)polymerase-1 cleavage. Moreover, licofelone induced the cleavage of the full-length p21(Bax) into p18(Bax), a more potent inducer of the apoptotic process than the uncleaved form. Pre-treatment of HCA-7 cells with the pan-caspase inhibitor z-VAD-fmk significantly blocked licofelone-induced apoptosis, confirming that this process occurred primarily in a caspase-dependent pathway. We also present evidences that licofelone was able to affect the arachidonic acid (AA) cascade, as it blocked the activity of 5-LOX and COX enzymes, and it induced, through the phosphorylation of cytoplasmic phospholipase A(2) (cPLA(2)), the release of unesterified AA from HCA-7 membrane phospholipids. However, apoptosis induction was not related to the ability of licofelone to affect the AA cascade, since neither exogenous prostaglandin E(2) and leukotriene B(4) addition, nor pharmacological inhibition of cPLA(2), was able to rescue HCA-7 cells from apoptosis. Even if further studies are needed to clarify the mechanism of licofelone-induced apoptosis, this study suggests that this drug, as well as similar dual COX/5-LOX inhibitors, may represent a novel and promising approach in colon cancer treatment.

HETEs enhance IL-1-mediated COX-2 expression via augmentation of message stability in human colonic myofibroblasts

Proinflammatory cytokines and eicosanoids are central players in intestinal inflammation. IL-1, a key cytokine associated with intestinal mucosal inflammation, induces COX-2 expression in human colonic myofibroblasts (CMF) and increased prostaglandin E(2) secretion is associated with inflammatory bowel disease (IBD) and colorectal cancer (CRC). We have previously demonstrated that IL-1alpha-induced cyclooxygenase-2 (COX-2) expression is the result of NF-kappaB- and ERK-mediated transcription, as well as COX-2 message stabilization, which depends on p38, MAPKAPK-2 (MK-2) and human antigen R (HuR) RNA binding protein activation. Lipoxygenase (LOX)-derived hydroxyeicosatetraenoic acids (HETEs) are elevated in IBD and colonic adenomas and "cross talk" has been observed between the COX and LOX pathways. Since COX-2 expression is primarily in CMFs in colonic adenomas, we examined the impact of LOX metabolites, particularly HETEs, on IL-1alpha-induced COX-2 expression in human CMFs. Although 5(S)-, 12(R)-, and 15(S)-HETEs alone had little to no effect on COX-2 expression, they enhanced IL-1-mediated COX-2 expression 3.6 +/- 0.5-fold. Studies utilizing heterogeneous nuclear RNA amplification and 5,6-dichloro-beta-d-ribofuranosylbenzimidazole treatment were undertaken to measure COX-2 transcription and message stabilization, respectively. We found that HETEs enhanced IL-1-induced COX-2 mRNA levels in CMF as the result of increased p38, MK-2, and HuR activity, increasing message stability greater than that observed with IL-1 alone. Thus HETEs can act synergistically with IL-1alpha to induce COX-2 expression in human CMFs. HETEs may play a role in both colonic inflammation and in increasing the risk of CRC in IBD independently and via induction of COX-2-mediated prostaglandin secretion.

Comparative protection against liver inflammation and fibrosis by a selective cyclooxygenase-2 inhibitor and a nonredox-type 5-lipoxygenase inhibitor

In this study, we examined the relative contribution of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO), two major proinflammatory pathways up-regulated in liver disease, to the progression of hepatic inflammation and fibrosis. Separate administration of 4-[5-(4-chlorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (SC-236), a selective COX-2 inhibitor, and CJ-13,610, a 5-LO inhibitor, to carbon tetrachloride-treated mice significantly reduced fibrosis as revealed by the analysis of Sirius Red-stained liver sections without affecting necroinflammation. Conversely, combined administration of SC-236 and 4-[3-[4-(2-methylimidazol-1-yl)-phenylthio]]phenyl-3,4,5,6-tetrahydro-2H-pyran-4-carboxamide (CJ-13,610) reduced both necroinflammation and fibrosis. These findings were confirmed in 5-LO-deficient mice receiving SC-236, which also showed reduced hepatic monocyte chemoattractant protein 1 expression. Interestingly, SC-236 and CJ-13,610 significantly increased the number of nonparenchymal liver cells with apoptotic nuclei (terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive). Additional pharmacological profiling of SC-236 and CJ-13,610 was performed in macrophages, the primary hepatic inflammatory cell type. In these cells, SC-236 inhibited prostaglandin (PG) E2 formation in a concentration-dependent manner, whereas CJ-13,610 blocked leukotriene B4 biosynthesis. Of note, the simultaneous addition of SC-236 and CJ-13,610 resulted in a higher inhibitory profile on PGE2 biosynthesis than the dual COX/5-LO inhibitor licofelone. These drugs differentially regulated interleukin-6 mRNA expression in macrophages. Taken together, these findings indicate that both COX-2 and 5-LO pathways are contributing factors to hepatic inflammation and fibrosis and that these two pathways of the arachidonic acid cascade represent potential targets for therapy.

The homeopathic antiarthitic preparation Zeel comp. N: a review of molecular and clinical data

Zeel comp. N (Zeel) is a homeopathic medication that has been widely used for many years for the treatment of arthritic disorders in a large number of countries worldwide. In recent years, a growing body of clinical and molecular evidence has been accumulating that shed light on the possible antiarthritic effects of this preparation. A number of studies report anti-inflammatory effects from Zeel. In vitro studies have indicated Zeel-mediated inhibition of the pathways involving the enzymes cyclooxygenase-1 and -2, and also the 5-lipoxygenase pathways, affecting levels of both eicosanoids and leukotrienes. Thus, Zeel may reduce the main two classes of molecules responsible for arthritic pain and inflammation. This review describes recent research on Zeel and discusses the need for further studies to clarify the role of the compound in the antiarthritic armamentarium of complementary medicine.

COX-2 and the kidney

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of pain and inflammation. Nonselective NSAIDs inhibit both cyclooxygenase (COX)-1 and COX-2. Nephrotoxicity of nonselective NSAIDs has been well documented. The effects of selective COX-2 inhibitors on renal function and blood pressure are attracting increasing attention. In the kidney, COX-2 is constitutively expressed and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in the mediation of renin release, regulation of sodium excretion, and maintenance of renal blood flow. Similar to nonselective NSAIDs, inhibition of COX-2 may cause edema and modest elevations in blood pressure in a minority of subjects. COX-2 inhibitors may also exacerbate preexisting hypertension or interfere with other antihypertensive drugs. Occasional acute renal failure has also been reported. Caution should be taken when COX-2 inhibitors are prescribed, especially in high-risk patients (including elderly patients and patients with volume depletion).

Update on cyclooxygenase-2 inhibitors

Nonsteroidal anti-inflammatory drugs represent the most commonly used medications for the treatment of pain and inflammation, but numerous well-described side effects can limit their use. Cyclooxygenase-2 (COX-2) inhibitors were initially touted as a therapeutic strategy to avoid not only the gastrointestinal but also the renal and cardiovascular side effects of nonspecific nonsteroidal anti-inflammatory drugs. However, in the kidney, COX-2 is constitutively expressed and is highly regulated in response to alterations in intravascular volume. COX-2 metabolites have been implicated in mediation of renin release, regulation of sodium excretion, and maintenance of renal blood flow. This review summarizes the current state of knowledge about both renal and cardiovascular side effects that are attributed to COX-2 selective inhibitors.

Urticaria: selected highlights and recent advances

Urticaria has been called a vexing problem and remains so today. The most important part of the diagnostic evaluation remains a comprehensive and detailed history and physical examination, supplemented with limited laboratory testing. Although acute urticaria has been relatively well understood for some time, significant and important recent advances in under-standing the pathogenesis of chronic urticaria are beginning to provide insight in this challenging field, notably the identification of many of these patients with an autoimmune etiology. Antihistamines of various types continue to represent the keystone of symptomatic treatment, with adjunctive support from medications of other classes, such as antileukotrienes, adrenergics, and immunosuppressive and anti-inflammatory agents (including steroids and cyclosporine). Although some progress has been made at improving symptomatic control of urticaria, further research and discovery are necessary before there can yet be an effective impact on the underlying course and natural history of this condition.

Superiority of the gastroduodenal safety profile of licofelone over rofecoxib, a COX-2 selective inhibitor, in dogs

This study assessed the gastroduodenal safety profile of licofelone, a new nonsteroidal anti-inflammatory drug with dual inhibitory activity against 5-lipoxygenase and cyclo-oxygenase (COX), by using endoscopic evaluations and by comparing licofelone to rofecoxib, a selective COX-2 inhibitor. Twenty-one dogs underwent blinded gastroduodenoscopies, during which the mucosa of the gastroduodenal tract was assessed and scored. Blood analyses were monitored on days 0 (baseline), 14, 28, 42, and 56. Examinations to detect fecal occult blood were performed daily. Dogs were randomly assigned to three groups that received either a placebo, licofelone at a dose of 2.5 mg/kg twice daily, or rofecoxib at a dose of 0.5 mg/kg daily, respectively. Significant differences between the groups in gastric (P = 0.003), duodenal (P = 0.009), and gastroduodenal (P = 0.002) endoscopic lesion scores were observed at day 56. Rofecoxib-treated dogs had more lesions in all areas when compared with placebo-treated dogs, more duodenal lesions when compared with licofelone-treated dogs and more lesions than they had at baseline. In contrast to licofelone, rofecoxib was found to induce significant gastric and gastroduodenal lesions in dogs that lacked pre-existing lesions at baseline. Blood analyses and fecal examinations did not reveal abnormalities in any of the experimental groups. Treatment with licofelone was well tolerated and was shown to be safer than rofecoxib in terms of upper gastrointestinal damage. In this way, this study demonstrates the gastroduodenal safety profile of licofelone for chronic treatment.

Regulation of the expression of 5-lipoxygenase-activating protein/5-lipoxygenase and the synthesis of leukotriene B(4) in osteoarthritic chondrocytes: role of transforming growth factor beta and eicosanoids

OBJECTIVE

To explore the modulation of 5-lipoxygenase-activating protein (FLAP) and 5-lipoxygenase (5-LOX) expression in human osteoarthritic (OA) chondrocytes, their relative implications in leukotriene B(4) (LTB(4)) production, the effect of different factors on this system, and the influence of increased LTB(4) production on the synthesis of catabolic factors of cartilage.

METHODS

FLAP and 5-LOX expression and LTB(4) production were monitored following treatment with transforming growth factor beta1 (TGFbeta1; 5 ng/ml) and 1,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3); 50 nM) alone or in combination with selective or nonselective cyclooxygenase (COX) inhibitors, naproxen (90 mug/ml), NS-398 (10 muM), or FR122047 (5 muM), or a dual inhibitor of COX/5-LOX activity, licofelone (2.6 muM). LTB(4), prostaglandin E(2) (PGE(2)), and matrix metalloprotease 1 (MMP-1) production were measured by specific enzyme-linked immunosorbent assays, nitric oxide by the Griess reaction, and FLAP and 5-LOX expression by quantitative polymerase chain reaction.

RESULTS

Human OA chondrocytes expressed both FLAP and 5-LOX. TGFbeta1 and/or 1,25(OH)(2)D(3) induced a rapid and marked enhancement ( approximately 4-13-fold) in FLAP messenger RNA (mRNA) levels, which was associated with a subsequent and late increase in LTB(4) production and PGE(2) synthesis. Treatment with COX inhibitors in the absence or presence of TGFbeta1 and 1,25(OH)(2)D(3) induced a rapid increase in LTB(4) production; this response was mediated by the sustained and significant (P < 0.01) up-regulation ( approximately 1.5-fold) of 5-LOX mRNA levels. Conversely, treatment with licofelone showed no effect on 5-LOX but significantly reduced FLAP expression levels. Coincubation of licofelone with TGFbeta1 plus 1,25(OH)(2)D(3) did not affect FLAP or 5-LOX levels. In the presence of TGFbeta1 plus 1,25(OH)(2)D(3), naproxen, but not licofelone, induced MMP-1 production and both drugs decreased nitric oxide levels.

CONCLUSION

Both the eicosanoids PGE(2) and LTB(4) are important cofactors in regulating FLAP/5-LOX expression; the inhibition of PGE(2) up-regulates 5-LOX while down-regulating FLAP gene expression, and LTB(4) appears to be an up-regulating factor on the 5-LOX gene. Importantly, nonsteroidal antiinflammatory drugs up-regulate the synthesis of LTB(4), supporting the shunt hypothesis from COX to 5-LOX. We also demonstrated that LTB(4) likely contributes to the up-regulation of important catabolic factors involved in the pathophysiology of OA, such as MMP.