Enhanced gastric mucosal leukotriene B4 synthesis in patients taking non-steroidal anti-inflammatory drugs

Discovery of new thymol-3,4-disubstituted thiazole hybrids as dual COX-2/5-LOX inhibitors with in vivo proof

New thymol-3,4-disubstitutedthiazole hybrids were synthesised as dual COX-2/5-LOX inhibitors. Compounds 6b, 6d, 6e, and 6f displayed in vitro inhibitory activity against COX-2 (IC50= 0.037, 0.042, 0.046, and 0.039 µM) nearly equal to celecoxib (IC50= 0.045 µM). 6b, 6d, and 6f showed SI (379, 341, and 374, respectively) higher than that of celecoxib (327). 6a-l elicited in vitro 5-LOX inhibitory activity higher than quercetin. 6a-f, 6i-l, 7a, and 7c possessed in vivo inhibition of formalin induced paw edoema higher than celecoxib. 6a, 6b, 6f, 6h-l, and 7b showed gastrointestinal safety profile as celecoxib and diclofenac sodium in the population of fasted rats. Induced fit docking and molecular dynamics simulation predicted good fitting of 6b and 6f without changing the packing and globularity of the apo protein. In conclusion, 6b and 6f achieved the target goal as multitarget inhibitors of inflammation.

A story of the potential effect of non-steroidal anti-inflammatory drugs (NSAIDs) in Parkinson's disease: beneficial or detrimental effects

Parkinson's disease (PD) is an advanced neurodegenerative disease (NDD) caused by the degeneration of dopaminergic neurons (DNs) in the substantia nigra (SN). As PD is an age-related disorder, the majority of PD patients are associated with musculoskeletal disorders with prolonged use of analgesic and anti-inflammatory agents, such as non-steroidal anti-inflammatory drugs (NSAIDs). Therefore, NSAIDs can affect PD neuropathology in different ways. Thus, the objective of the present narrative review was to clarify the potential role of NSAIDs in PD according to the assorted view of preponderance. Inhibition of neuroinflammation and modulation of immune response by NSAIDs could be an effective way in preventing the development of NDD. NSAIDs affect PD neuropathology in different manners could be beneficial or detrimental effects. Inhibition of cyclooxygenase 2 (COX2) by NSAIDs may prevent the development of PD. NSAIDs afforded a neuroprotective role against the development and progression of PD neuropathology through the  modulation of neuroinflammation. Though, NSAIDs may lead to neutral or harmful effects by inhibiting neuroprotective prostacyclin (PGI2) and accentuation of pro-inflammatory leukotrienes (LTs). In conclusion, there is still a potential conflict regarding the effect of NSAIDs on PD neuropathology.

Looking at NSAIDs from a historical perspective and their current status in drug repurposing for cancer treatment and prevention

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently prescribed drug classes with wide therapeutic applications over the centuries. Starting from the use of salicylate-containing willow leaves to the recent rise and fall of highly selective cyclooxygenase-2 (COX-2) inhibitors and the latest dual-acting anti-inflammatory molecules, they have displayed a rapid and ongoing evolution. Despite the enormous advances in the last twenty years, investigators are still in search of the design and development of more potent and safer therapy against inflammatory conditions. This challenge has been increasingly attractive as the emergence of inflammation as a common seed and unifying mechanism for most chronic diseases. Indeed, this fact put the NSAIDs in the spotlight for repurposing against inflammation-related disorders. This review attempts to present a historical perspective on the evolution of NSAIDs, regarding their COX-dependent/independent mode of actions, structural and mechanism-based classifications, and adverse effects. Additionally, a systematic review of previous studies was carried out to show the current situation in drug repurposing, particularly in cancers associated with the GI tract such as gastric and colorectal carcinoma. In the case of non-GI-related cancers, preclinical studies elucidating the effects and modes of action were collected and summarized.

Pain killers: the interplay between nonsteroidal anti-inflammatory drugs and Clostridioides difficile infection

Clostridioides difficile is one of the leading causes of nosocomial infections worldwide. Increases in incidence, severity, and healthcare cost associated with C. difficile infection (CDI) have made this pathogen an urgent public health threat worldwide. The factors shaping the evolving epidemiology of CDI and impacting clinical outcomes of infection are not well understood, but involve tripartite interactions between the host, microbiota, and C. difficile. In addition to this, emerging data suggests an underappreciated role for environmental factors, such as diet and pharmaceutical drugs, in CDI. In this review, we discuss the role of nonsteroidal anti-inflammatory drugs (NSAIDs) and eicosanoids in CDI.

Efficacy and Safety of Polyphenols for Osteoarthritis Treatment: a Meta-Analysis

PURPOSE

Osteoarthritis (OA) is a chronic and degenerative disorder associated with joint pain and loss of joint function. It is reported that polyphenols could yield articular benefits in patients with OA through the inhabitation of key inflammatory pathways. This meta-analysis was conducted to assess the efficacy and safety of polyphenol products for OA treatment.

METHODS

This study included searches of PubMed, EMBASE, and the Cochrane Library databases from inception to November 6, 2019. Randomized controlled trials (RCTs) comparing polyphenols versus NSAIDs or placebo for human OA were included. Standardized mean differences (SMD) or risk ratios (RRs) were calculated for all relevant outcomes. Meta-analyses were conducted by using random effect models, and heterogeneity was assessed by using the I² statistic.

FINDINGS

A total of 18 RCTs (N = 1724) were eligible for analysis. Polyphenol products showed a significant advantage over placebo on pain relief (SMD, -1.11; 95% CI, -1.35 to -0.87) and functional improvement (SMD, -1.14; 95% CI, -1.38 to -0.90). No differences in safety outcomes were detected between polyphenols and placebo. There were no differences in efficacy outcomes between polyphenols and NSAIDs, although patients receiving polyphenols had a lower but nonsignificant risk of experiencing gastrointestinal dysfunction compared with those treated with NSAIDs. Polyphenols and NSAIDs in combination yielded more significant benefits in efficacy than NSAIDs alone.

IMPLICATIONS

The results of our study suggest that polyphenols may be a promising alternative for OA by relieving symptoms while reducing safety risks. However, the generalizability of our results may be limited by the quality and sample size of the available research, as well as the heterogeneity between RCTs. High-quality clinical trials are needed to make meaningful clinical practice recommendations.

Alkaloids of Adhatoda vasica Nees. as potential inhibitors of cyclooxygenases - an in-silico study

Eicosanoid pathways play a crucial role in the progression and resolution of inflammation. NSAIDs act as anti-inflammatory agents by inhibiting both the isoforms of cyclooxygenases (COXs) whereas, COXIBs act as specific COX-2 inhibitors. Excessive usage of the same is linked with gastrointestinal bleeding and increased cardiovascular risk, respectively. The current in-silico study was aimed at evaluating the potential of major alkaloids of A. vasica (vasicine (VAS), vasicinone (VAE), and Deoxyvasicine (DOV)) as inhibitors of COXs. The results of the computed binding energy (ΔG) indicate that Celecoxib (CEL), DOV, and VAS have a higher affinity to COX-2, while VAE has a higher affinity to COX-1, and Mefenamic acid (MEF) was not selective. Among the alkaloids, VAE exhibited the best ΔG (of -8.2 kcal/mol) with COX-1, while VAS exhibited the best ΔG (of -8.2 kcal/mol) with COX-2. This was comparable to the ΔG exhibited by Mefenamic acid (-8.7 kcal/mol with both the COXs). With their potential to remain gastroprotective while having the ability to inhibit enzymes of both the prostaglandin and leukotriene pathways, the alkaloids of A. vasica could be promising leads for the design of Eicosanoid pathway modulators/inhibitors.Communicated by Ramaswamy H. Sarma.

Mammalian-Like Inflammatory and Pro-Resolving Oxylipins in Marine Algae

Oxylipins constitute a family of oxidized fatty acids, that are well known as tissue hormones in mammals. They contribute to inflammation and its resolution. The major classes of these lipid mediators are inflammatory prostaglandins (PGs) and leukotrienes (LTs) as well as pro-resolving resolvins (Rvs). Understanding their biosynthetic pathways and modes of action is important for anti-inflammatory interventions. Besides mammals, marine algae also biosynthesize mammalian-like oxylipins and thus offer new opportunities for oxylipin research. They provide prolific sources for these compounds and offer unique opportunities to study alternative biosynthetic pathways to the well-known lipid mediators. Herein, we discuss recent findings on the biosynthesis of oxylipins in mammals and algae including an alternative pathway to prostaglandin E2 , a novel pathway to a precursor of leukotriene B4 , and the production of resolvins in algae. We evaluate the pharmacological potential of the algal metabolites with implications in health and disease.

15-Hydroperoxy-PGE2 : Intermediate in Mammalian and Algal Prostaglandin Biosynthesis

Arachidonic‐acid‐derived prostaglandins (PGs), specifically PGE₂, play a central role in inflammation and numerous immunological reactions. The enzymes of PGE₂ biosynthesis are important pharmacological targets for anti‐inflammatory drugs. Besides mammals, certain edible marine algae possess a comprehensive repertoire of bioactive arachidonic‐acid‐derived oxylipins including PGs that may account for food poisoning. Described here is the analysis of PGE₂ biosynthesis in the red macroalga Gracilaria vermiculophylla that led to the identification of 15‐hydroperoxy‐PGE₂, a novel precursor of PGE₂ and 15‐keto‐PGE₂. Interestingly, this novel precursor is also produced in human macrophages where it represents a key metabolite in an alternative biosynthetic PGE₂ pathway in addition to the well‐established arachidonic acid‐PGG₂‐PGH₂‐PGE₂ route. This alternative pathway of mammalian PGE₂ biosynthesis may open novel opportunities to intervene with inflammation‐related diseases.

Novel aryl carboximidamide and 3-aryl-1,2,4-oxadiazole analogues of naproxen as dual selective COX-2/15-LOX inhibitors: Design, synthesis and docking studies

A series of novel naproxen analogues containing 3-aryl-1,2,4-oxadiazoles moiety (4b-g) and their reaction intermediates aryl carboximidamides moiety (3b-g) was synthesized and evaluated in vitro as dual COXs/15-LOX inhibitors. Compounds 3b-g exhibited superior inhibitory activity than celecoxib as COX-2 inhibitors. Compounds 3b-d and 3g were the most potent COX-2 inhibitors with IC50 range of 6.4 - 8.13 nM and higher selectivity indexes (3b, SI = 26.19; 3c, SI = 13.73; 3d, SI = 29.27; 3g, SI = 18.00) comparing to celecoxib (IC50 = 42.60 nM, SI = 8.05). Regarding 15-LOX inhibitory activity, compounds belonging to aryl carboximidamide backbone 3b-e and 3g were the most potent with IC50 range of 1.77-4.91 nM comparing to meclofenamate sodium (IC50 = 5.64 µM). Data revealed that The levels of NO released by aryl carboximidamides 3b-g were more higher than 3-aryl-1,2,4-oxadiazole derivatives 4b-g, which correlated well with their COX-2 inhibitory activities.

Eicosanoids in the gastrointestinal tract

Eicosanoids play important roles in modulating inflammation throughout the body. The gastrointestinal (GI) tract, in part because of its intimate relationship with the gut microbiota, is in a constant state of low-grade inflammation. Eicosanoids like PGs, lipoxins and leukotrienes play essential roles in maintenance of mucosal integrity. On the other hand, in some circumstances, these mediators can become major drivers of inflammatory processes when the lining of the GI tract is breached. Drugs such as nonsteroidal anti-inflammatories, by altering the production of various eicosanoids, can dramatically impact the ability of the GI tract to respond appropriately to injury. Disorders such as inflammatory bowel disease appear to be driven in part by altered production of eicosanoids. Several classes of drugs have been developed that target eicosanoids. LINKED ARTICLES: This article is part of a themed section on Eicosanoids 35 years from the 1982 Nobel: where are we now? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.8/issuetoc.

The role of the LTB4-BLT1 axis in chemotactic gradient sensing and directed leukocyte migration

Directed leukocyte migration is a hallmark of inflammatory immune responses. Leukotrienes are derived from arachidonic acid and represent a class of potent lipid mediators of leukocyte migration. In this review, we summarize the essential steps leading to the production of LTB₄ in leukocytes. We discuss the recent findings on the exosomal packaging and transport of LTB₄ in the context of chemotactic gradients formation and regulation of leukocyte recruitment. We also discuss the dynamic roles of the LTB₄ receptors, BLT1 and BLT2, in mediating chemotactic signaling in leukocytes and contrast them to other structurally related leukotrienes that bind to distinct GPCRs. Finally, we highlight the specific roles of the LTB₄-BLT1 axis in mediating signal-relay between chemotaxing neutrophils and its potential contribution to a wide variety of inflammatory conditions including tumor progression and metastasis, where LTB₄ is emerging as a key signaling component.

Inhibition of pro-inflammatory enzymes by medicinal plants from the Argentinean highlands (Puna)

ETHNOPHARMACOLOGICAL RELEVANCE

Human groups in the Argentinean Andes highlands (Puna) selected native plants as anti-inflammatory agents. The indications of use are mainly to relieve pain, as infusions, ethanolic extracts or plasters.

AIM OF THE STUDY

The objective of the study was to assess the effect of hydroalcoholic extracts from native highland plants as anti-inflammatory agents according to the traditional indications of use. The chemical profile of the three most active species was analyzed by HPLC-ESI-MS to get an insight into the constituents and the effects observed according to the ethnopharmacological information.

MATERIALS AND METHODS

Hydroalcoholic extracts from 13 Argentinean Puna plants used as anti-inflammatory were evaluated as inhibitors of the pro-inflammatory enzymes phospholipase A₂ (sPLA₂), lipoxygenase (LOX), hyaluronidase, and for their capacity to stabilize red blood cells membrane. In addition, the extracts were evaluated to determine their reducing power, iron chelating capacity and ABTS^•+ radical scavenging effect. The chemical profiles of the most active species were analyzed by HPLC-ESI-MS.

RESULTS

Among the species investigated, Ephedra multiflora was the most active as LOX inhibitor (IC₅₀:132µg/mL), by reducing the non-heme iron group and by scavenging radicals. The IC₅₀ values of the reference compounds caffeic acid and naproxen were 57.0 and 14.0µg/mL, respectively. Parastrephia lucida showed the highest sPLA₂ inhibitory effect (63% of inhibition at 200µg/mL). Under the same experimental conditions, the IC₅₀ of the reference compound acetylsalicylic acid was 65±1µg/mL. Tessaria absinthioides exhibited the best inhibition towards hyaluronidase with an IC₅₀ of 93.2±4.3µg/mL. Under the same experimental conditions, the reference compounds quercetin and indomethacin presented IC₅₀ values of 340.0±17.0 and 502.0±10.0µg/mL, respectively. Among the most active species, 13 compounds were tentatively identified by HPLC-ESI-MS in E. multiflora and P. lucida, and 12 compounds in T. absinthioides. The constituents included caffeoyl- and feruloylquinic acid derivatives, flavonoids, simple phenolics and sesquiterpene glycosides.

CONCLUSIONS

Six out of the 13 species investigated showed a moderate to strong effect towards the enzyme sPLA₂ (>40% inhibition at 200µg/mL) while three species presented a strong activity against LOX with IC₅₀<250µg/mL and three were very active against hyaluronidase. Most of the crude drug extracts were able to stabilize the red blood cells membrane, preventing their lysis. The compounds identified in the extracts explain, at least in part, the activity found in the samples. The effect observed for the most active species supports their traditional use as anti-inflammatory agents. However, more studies should be undertaken to disclose the potential of the Puna plants as anti-inflammatory crude drugs.

Alleviating Promotion of Inflammation and Cancer Induced by Nonsteroidal Anti-Inflammatory Drugs

Clinical Relevance

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) including aspirin are of intensive use nowadays. These drugs exert their activity via the metabolism of arachidonic acid (AA) by cyclooxygenase inhibition. Though beneficial for health in some instances, both unspecific and specific cyclooxygenase inhibitor activity interfere with AA metabolism producing also proinflammatory lipids that may promote cancer.

Materials and Methods

This review is based on available literature on clinical uses, biochemical investigations, molecular medicine, pharmacology, toxicity, and epidemiology-clinical studies on NSAIDs and other drugs that may be used accordingly, which was collected from electronic (SciFinder, Medline, Science Direct, and ACS among others) and library searches of books and journals.

Results

Relevant literature supports the notion that NDSAID use may also promote proinflammatory biochemical events that are also related to precancerous predisposition. Several agents are proposed that may be employed in immediate future to supplement and optimize treatment with NSAIDs. In this way serious side effects arising from promotion of inflammation and cancer, especially in chronic NSAID users and high risk groups of patients, could be avoided.

Inhibition of 5-lipoxygenase by zileuton in a rat model of myocardial infarction

OBJECTIVE

The goal of the present study was to investigate the effects of 5-lipoxygenase (5-LOX) inhibition, alone and with cyclooxygenase (COX) inhibitors, on inflammatory parameters and apoptosis in ischemia/reperfusion (I/R)-induced myocardial damage in rats. For this purpose, zileuton, a selective and potent inhibitor of 5-LOX, resulting in suppression leukotriene production, was used.

METHODS

Male Wistar rats (200-250 g; n=12 per group) were used in the study. I/R was performed by occluding the left coronary artery for 30 minutes and 2 hours of reperfusion of the heart. Experimental groups were I/R group, sham I/R group, zileuton (5 mg/kg orally, twice daily)+I/R group, zileuton+indomethacin (5 mg/kg intraperitoneally)+I/R group, zileuton+ketorolac (10 mg/kg subcutaneously)+I/R group, and zileuton+nimesulide (5 mg/kg subcutaneously)+I/R group. Following I/R, blood samples were collected to measure tumor necrosis factor alpha (TNF-α), and left ventricles were excised for evaluation of microscopic damage; malondialdehyde (MDA), glutathione, nuclear factor (NF)-κB assays; and evaluation of apoptosis.

RESULTS

Left ventricle MDA in I/R group was higher compared to sham group; however, it did not show significant change with zileuton. Although tissue injury in I/R group was less severe in all treatment groups, it was not statistically significant. NF-κB H-score and apoptotic index, which were higher in I/R group compared to sham I/R, were decreased with application of zileuton (H-score: p<0.01; apoptotic index: p<0.001). Zileuton had no significant effect on increased serum TNF-α levels in I/R group.

CONCLUSION

5-LOX inhibition in rat myocardial infarction model attenuated increased left ventricle NF-κB expression and apoptosis and these actions were not modulated by COX inhibitors.

NSAIDs and Cardiovascular Diseases: Role of Reactive Oxygen Species

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most commonly used drugs worldwide. NSAIDs are used for a variety of conditions including pain, rheumatoid arthritis, and musculoskeletal disorders. The beneficial effects of NSAIDs in reducing or relieving pain are well established, and other benefits such as reducing inflammation and anticancer effects are also documented. The undesirable side effects of NSAIDs include ulcers, internal bleeding, kidney failure, and increased risk of heart attack and stroke. Some of these side effects may be due to the oxidative stress induced by NSAIDs in different tissues. NSAIDs have been shown to induce reactive oxygen species (ROS) in different cell types including cardiac and cardiovascular related cells. Increases in ROS result in increased levels of oxidized proteins which alters key intracellular signaling pathways. One of these key pathways is apoptosis which causes cell death when significantly activated. This review discusses the relationship between NSAIDs and cardiovascular diseases (CVD) and the role of NSAID-induced ROS in CVD.

Anti-inflammatory and antinociceptive activities of Homalium letestui

CONTEXT

Homalium letestui Pellegr (Flacourtiaceae) is used in various decoctions traditionally by the Ibibios of the Niger Delta of Nigeria to treat stomach ulcer, malaria and other inflammatory diseases, as well as an aphrodisiac.

OBJECTIVE

To investigate the anti-inflammatory and antinociceptive activities of the stem extract of the plant.

MATERIALS AND METHODS

The ethanol stem extract (500, 750, 1000 mg/kg, i.p.) of H. letestui was investigated for anti-inflammatory activity using carrageenan, egg albumin-induced and xylene-induced ear edema models and analgesic activity using acetic acid-induced writhing, formalin-induced paw licking and thermal-induced pain models. The ethanol extract was administered to the animals orally, 30 min to 1 h depending on the model, before induction of inflammation/pain. The LD50 was also determined. GC-MS analysis of dichloromethane fraction was carried out.

RESULTS

The extract caused a significant (p < 0.05-0.001) reduction of inflammation induced by carrageenan (8.3-70.0%), egg albumin (10.0-71.42%) and xylene (39.39-84.84%). The extract also reduced significantly (p < 0.05-0.001) pain induced by acetic acid (44.22-73.65%), formalin (55.89-79.21%) and hot plate (93.0-214.5%). The LD50 was determined to be 4.38 ± 35.72 g/kg.

DISCUSSION AND CONCLUSION

The results of this study suggest that the ethanol stem extract of H. letestui possesses anti-inflammatory and analgesic properties which may in part be mediated through the chemical constituents of the plant as revealed by the GC-MS.

Role of drug-independent stress factors in liver injury associated with diclofenac intake

Although a basic understanding of the chemical and biological events leading to idiosyncratic drug toxicity is still lacking, it appears that drug-independent risk factors that increase reactive metabolite formation or alter cellular stress and immune response may be critical determinants in the response to an otherwise non-toxic drug. Thus, we were interested to determine the impact of various drug-independent stress factors - lipopolysaccharide (LPS), poly I:C (PIC) or glutathione depletion via buthionine sulfoximine (BSO) - on the toxicity of diclofenac (Dcl), a model drug associated with rare but significant cases of serious hepatotoxicity, and to understand if enhanced toxicity occurs through alterations of drug metabolism and/or modulation of stress response pathways. Co-treatment of rats repeatedly given therapeutic doses of Dcl for 7 days with a single dose of LPS 2h before the last Dcl dose resulted in severe liver toxicity. Neither LPS nor diclofenac alone or in combination with PIC or BSO had such an effect. While it is thought that bioactivation to reactive Dcl acyl glucuronides (AG) and subsequent protein adduct formation contribute to Dcl induced liver injury, LC-MS/MS analyses did not reveal increased formation of 4'- and 5-hydroxy-Dcl, Dcl-AG or Dcl-AG dependent protein adducts in animals treated with LPS/Dcl. Hepatic gene expression analysis suggested enhanced activation of NFκB and MAPK pathways and up-regulation of co-stimulatory molecules (IL-1β, TNF-α, CINC-1) by LPS/Dcl and PIC/Dcl, while protective factors (HSPs, SOD2) were down-regulated. LPS/Dcl led to extensive release of pro-inflammatory cytokines (IL-1β, IL-6, IFN-γ, TNF-α) and factors thought to constitute danger signals (HMGB1, CINC-1) into plasma. Taken together, our results show that Dcl enhanced the inflammatory response induced by LPS - and to a lesser extent by PIC - through up-regulation of pro-inflammatory molecules and down-regulation of protective factors. This suggests sensitization of cells to cellular stress mediated by non-drug-related risk factors by therapeutic doses of Dcl, rather than potentiation of Dcl toxicity by the stress factors.

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.

Dual role of cyclooxygenase-2 during tissue repair induced by low level laser therapy: an intriguing issue

Tissue repair is an excellent example of pathophysiological model for studying the role of cyclooxygenase-2 (COX-2) on eukaryotic cells. It has been established that two COX isoforms are expressed in human tissues: constitutive or induced. COX-1 activity is constitutive, present in nearly all cell types at a constant level; COX-2 activity is normally absent from cells, and when induced, the protein levels increase and decrease in a matter of hours after a single stimulus. Thus, the purpose of this review was to describe the role of COX-2 during tissue repair induced by low level laser therapy (LLLT) in humans and experimental models. COX-2 expression has been implicated in the onset or the exacerbation of inflammation during tissue repair induced by LLLT in a number of studies, Many studies are conducted to investigate the role of COX-2 during tissue repair induced by LLLT using different experimental protocols and dosages. Therefore, this is an area that warrants investigation, since the estimation of COX-2 expression from using such important techniques in therapeutics with respect to tissue repair will be added to those already established in the literature as a way to improve health status and prevention of side effects.

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.

A medicinal plant extract of Scutellaria Baicalensis and Acacia catechu reduced LPS-stimulated gene expression in immune cells: a comprehensive genomic study using QPCR, ELISA, and microarray

A standardized, combined flavonoid extracts of Scutellaria baicalensis and Acacia catechu, UP446, demonstrates favorable anti-inflammatory properties. In this study, DNA microarray, quantitative polymerase chain reaction (QPCR), and enzyme-linked immunosorbent assay (ELISA) were used to study the effect of UP446 on the lipopolysaccharide (LPS)-induced pro-inflammatory gene regulation of both animal and human immortalized cell lines and also primary human cells. One consistent result from microarray was that the gene expression levels stimulated or suppressed by LPS were returned to normal levels by the UP446 co-treatment. This normalization effect from UP446 was also shown for pro-inflammatory genes cyclooxygenase (COX)-2, tissue necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 using QPCR, and TNF-α using ELISA. The controlling transcriptional factor of these genes, NFκB, was also down-regulated by UP446 in the LPS-induced cell models. Microarray analysis for numerous genes, including cytokines, chemokines, receptors, transcriptional factors, caspase, growth factors, and phosphatases, suggests not only a genomic anti-inflammatory activity for UP446 but also signaling pathways of cell proliferation, cell death, and lipid metabolism demonstrated on different types of cells.

Quercetin alleviates hypercholesterolemic diet induced inflammation during progression and regression of atherosclerosis in rabbits

OBJECTIVE

Recent advances have established a fundamental role for inflammation in mediating all stages of atherosclerosis, from initiation through progression. Quercetin may be a powerful bioactive constituent of the human diet, as a free radical scavenging agent and through interactions with various endogenous proteins. The present study focused on the effect of quercetin on inflammation induced by a hypercholesterolemic diet (HCD) in rabbits.

METHODS

The animals were subjected to two different experiments, atherosclerotic progression and regression. In the atherosclerotic progression study, quercetin (25 mg/kg of body weight) was administered with the HCD for 90 d. In the atherosclerotic regression study, the animals were fed with the HCD for 90 d and then supplemented with quercetin (25 mg/kg of body weight) for another 90 d. The inflammatory enzyme activities were examined and a histopathologic examination of the aorta was performed.

RESULTS

In the atherosclerotic progression study, quercetin coadministered with the HCD significantly decreased the activities of inflammatory enzymes such as cyclooxygenase, lipoxygenases (LOX) such as 5-LOX and 12-LOX in monocytes, nitric oxide synthase activity in the plasma, myeloperoxidase activity in the aorta, and the level of C-reactive protein in serum. In the regression study, quercetin administration significantly decreased the increased activities of inflammatory mediators such as cyclooxygenase, 5-LOX, 12-LOX, myeloperoxidase, and nitric oxide synthase and the serum level of C-reactive protein in HCD-fed rabbits compared with regression control rabbits. This effect was confirmed by histopathologic examination of the aorta.

CONCLUSION

This study demonstrates that quercetin modulates the deleterious inflammatory effects induced by an HCD in vivo in rabbits, suggesting its beneficial effect in decreasing inflammation in atherosclerotic progression and regression.

Bioactivity-guided fractionation of the lipoxygenase and cyclooxygenase inhibiting constituents from Chisocheton polyandrus Merr

Lipoxygenase (LOX)-inhibiting compounds from the leaves of Chisocheton polyandrus Merr. were isolated in this study using a bioactivity-guided fractionation technique. Two dammarane triterpenoids, dammara-20,24-dien-3-one (1) (IC(50)=0.69±0.07 μM) and 24-hydroxydammara-20,25-dien-3-one (2) (IC(50)=1.11±0.38 μM), were isolated and identified based on the soybean LOX assay. Dammara-20,24-dien-3-one (1) exhibited dual inhibition of both human 5-LOX (IC(50)=24.27±2.92 μM) and cyclooxygenase-2 (COX-2) (IC(50)=3.17±0.90 μM), whereas 24-hydroxydammara-20,25-dien-3-one (2) did not exhibit any significant inhibitory effects. This report is the first to detail the inhibition of LOX and COX by both C. polyandrus and its isolated compounds.

5-Lipoxygenase metabolic contributions to NSAID-induced organ toxicity

Cyclooxygenase (COX)-1, COX-2, and 5-lipoxygenase (5-LOX) enzymes produce effectors of pain and inflammation in osteoarthritis (OA) and many other diseases. All three enzymes play a key role in the metabolism of arachidonic acid (AA) to inflammatory fatty acids, which contribute to the deterioration of cartilage. AA is derived from both phospholipase A(2) (PLA(2)) conversion of cell membrane phospholipids and dietary consumption of omega-6 fatty acids. Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit the COX enzymes, but show no anti-5-LOX activity to prevent the formation of leukotrienes (LTs). Cysteinyl LTs, such as LTC(4), LTD(4), LTE(4), and leukoattractive LTB(4) accumulate in several organs of mammals in response to NSAID consumption. Elevated 5-LOX-mediated AA metabolism may contribute to the side-effect profile observed for NSAIDs in OA. Current therapeutics under development, so-called "dual inhibitors" of COX and 5-LOX, show improved side-effect profiles and may represent a new option in the management of OA.

Anti-inflammatory potential of an ethyl acetate fraction isolated from Justicia gendarussa roots through inhibition of iNOS and COX-2 expression via NF-κB pathway

Justicia gendarussa Burm.f. (J. gendarussa) is a plant used as traditional medicine in different parts of India and China to treat inflammatory disorders like rheumatoid arthritis. But its mechanism of anti-inflammatory action is still unclear. Hence in this context, the objective of our study is to reveal the mechanism of anti-inflammatory activity of J. gendarussa which would form an additional proof to the traditional knowledge of this plant. The anti-inflammatory function and mechanism(s) of action was studied in an ethyl acetate fraction isolated from methanolic extract of J. gendarussa roots (EJG). Anti-inflammatory studies were conducted on rats using partitioned fractions isolated from methanolic extract of J. gendarussa roots. In carrageenan-induced rat paw edema, ethyl acetate fraction brought about 80% and 93% edema inhibition at 3rd and 5th hour at a dose of 50 mg/kg, when compared to other extracts and Voveran. We investigated whether EJG inhibits the release of cycloxygenase (COX), 5-lipoxygenase (5-LOX), interleukin-6 (IL-6) and nuclear factor kappa B (NF-κB) in LPS stimulated human peripheral blood mononuclear cells (hPBMCs). Results shows that EJG dose dependently inhibited LPS-activated COX, 5-LOX, IL-6, and NF-κB in hPBMCs. EJG also reduced LPS induced levels of iNOS and COX-2 mRNA expression in hPBMCs. This study provides an insight into the probable mechanism(s) underlying the anti-inflammatory activity of EJG and therefore, we report the first confirmation of the anti-inflammatory potential of this traditionally employed herbal medicine in vitro.

Gastroprotective and safety effects of WIN-34B, a novel treatment for osteoarthritis, compared to NSAIDs

ETHNOPHARMACOLOGICAL RELEVANCE

The dried flowers of Lonicera japonica, also known as Japanese honeysuckle, and the dried root of Anemarrhena asphodeloides, the component herbs of WIN-34B, are traditionally used in Eastern medicine to treat various inflammatory conditions including arthritis.

OBJECTIVE

To study the acute and chronic toxicities of WIN-34B and to compare its effects on gastric mucosa with those of diclofenac, a widely used NSAID, and celecoxib, a selective COX-2 inhibitor.

MATERIALS AND METHODS

To investigate acute toxicity, we orally administered a single dose of 5,000 mg/kg WIN-34B to rats. To investigate chronic toxicity, we orally administered 500, 1000 or 2,000 mg/kg WIN-34B to rats daily for 13 weeks. To assess its effects on gastric mucosa, rats received either a single dose or repeated doses of WIN-34B (400, 1000, or 2,000 mg/kg), diclofenac (10, 40, or 80 mg/kg), celecoxib (100 or 1,000 mg/kg), or vehicle, after which samples of gastric mucosa were assessed grossly and histologically. We also measured tissue activity of myeloperoxidase and synthesis of eicosanoids, including prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)). To further assess its effects, we administered WIN-34B to rats either intraperitoneally or orally, measured gastric injury scores using a rat model of diclofenac-induced gastric injury, and measured eicosanoid synthesis.

RESULTS

WIN-34B showed no signs of acute or chronic toxicity in terms of general behavior, gross appearance of the internal organs, blood chemistry, or mortality. WIN-34B did not cause significant gastric mucosal damage after single or repeated doses. In contrast, diclofenac and celecoxib both caused gastric damage. In terms of eicosanoid synthesis, WIN-34B significantly suppressed LTB(4) synthesis while both diclofenac and celecoxib increased LTB(4) synthesis. WIN-34B slightly reduced PGE(2) production, while both diclofenac and celecoxib significantly reduced PGE(2) production. In a rat model of diclofenac-induced gastric injury, WIN-34B significantly suppressed LTB(4) synthesis and restored PGE(2) release.

CONCLUSIONS

These results demonstrate that WIN-34B did not cause acute or chronic toxicity in male or female rats. In addition, WIN-34B did not cause significant gastric mucosal damage, instead appearing to protect the mucosa from diclofenac-induced gastric damage through the regulation of PGE(2) and LTB(4).

Flavocoxid inhibits phospholipase A2, peroxidase moieties of the cyclooxygenases (COX), and 5-lipoxygenase, modifies COX-2 gene expression, and acts as an antioxidant

The multiple mechanisms of action for flavocoxid relating to arachidonic acid (AA) formation and metabolism were studied in vitro. Flavocoxid titrated into rat peritoneal macrophage cultures inhibited cellular phospholipase A2 (PLA(2)) (IC(50) = 60 μg/mL). In in vitro enzyme assays, flavocoxid showed little anti-cyclooxygenase (CO) activity on COX-1/-2 enzymes, but inhibited the COX-1 (IC(50) = 12.3) and COX-2 (IC(50) = 11.3 μg/mL) peroxidase (PO) moieties as well as 5-lipoxygenase (5-LOX) (IC(50) = 110 μg/mL). No detectable 5-LOX inhibition was found for multiple traditional and COX-2 selective NSAIDs. Flavocoxid also exhibited strong and varied antioxidant capacities in vitro and decreased nitrite levels (IC(50) = 38 μg/mL) in rat peritoneal macrophages. Finally, in contrast to celecoxib and ibuprofen, which upregulated the cox-2 gene, flavocoxid strongly decreased expression. This work suggests that clinically favourable effects of flavocoxid for management of osteoarthritis (OA) are achieved by simultaneous modification of multiple molecular pathways relating to AA metabolism, oxidative induction of inflammation, and neutralization of reactive oxygen species (ROS).

Flavocoxid, a dual inhibitor of cyclooxygenase-2 and 5-lipoxygenase, reduces pancreatic damage in an experimental model of acute pancreatitis

BACKGROUND AND PURPOSE

Acute pancreatitis is an autodigestive process resulting in acute inflammation of the pancreas. Accumulating evidence indicates the essential contribution of cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LOX) to acute pancreatitis. We studied the effects of flavocoxid, a plant-derived dual inhibitor of COX-2 and 5-LOX, in a model of caerulein (CER)-induced acute pancreatitis.

EXPERIMENTAL APPROACH

Rats were given CER (80 µg·kg⁻¹ for each of four injections at hourly intervals) or vehicle (Sham-CER). Animals were then randomized to receive flavocoxid (20 mg·kg⁻¹ i.p.) or vehicle, 30 min after the first CER injection. Two hours after the last CER injection, we evaluated damage to the pancreas by histological methods; serum levels of amylase, lipase, leukotriene (LT)B₄ and prostaglandin (PG)E₂ ; pancreatic expression of COX-2 and 5-LOX and tumour necrosis factor-α (TNF-α) gene expression by real-time polymerase chain reaction.

KEY RESULTS

Caerulein induced inflammatory changes in the pancreas and raised values of the other variables measured. In CER-treated animals, but not in those given saline, flavocoxid inhibited COX-2 and 5-LOX expression, reduced serum levels of lipase and amylase and the degree of pancreatic oedema. Treatment with flavocoxid blunted the increased pancreatic TNF-α mRNA expression, serum leukotriene B₄ and prostaglandin E₂ levels, and protected against histological damage in terms of vacuolization and leukocyte infiltration.

CONCLUSIONS AND IMPLICATIONS

Our results confirm the key role of both COX-2 and 5-LOX in the inflammatory response to acute pancreatitis. Flavocoxid may provide a potential therapeutic approach to the treatment of patients at high risk of developing this life-threatening condition.

Accelerated fracture healing in mice lacking the 5-lipoxygenase gene

BACKGROUND AND PURPOSE

Cyclooxygenase-2 (COX-2) promotes inflammation by synthesizing pro-inflammatory prostaglandins from arachidonic acid. Inflammation is an early response to bone fracture, and ablation of COX-2 activity impairs fracture healing. Arachidonic acid is also converted into leukotrienes by 5-lipoxygenase (5-LO). We hypothesized that 5-LO is a negative regulator of fracture healing and that in the absence of COX-2, excess leukotrienes synthesized by 5-LO will impair fracture healing.

METHODS

Fracture healing was assessed in mice with a targeted 5-LO mutation (5-LO(KO) mice) and control mice by radiographic and histological observations, and measured by histomorphometry and torsional mechanical testing. To assess effects on arachidonic acid metabolism, prostaglandin E2, F2α, and leukotriene B4 levels were measured in the fracture calluses of control, 5-LO(KO) COX-1(KO), and COX-2(KO) mice by enzyme linked immunoassays.

RESULTS

Femur fractures in 5-LO(KO) mice rapidly developed a cartilaginous callus that was replaced with bone to heal fractures faster than in control mice. Femurs from 5-LO(KO) mice had substantially better mechanical properties after 1 month of healing than did control mice. Callus leukotriene levels were 4-fold higher in mice homozygous for a targeted mutation in the COX-2 gene (COX-2(KO)), which indicated that arachidonic acid was shunted into the 5-LO pathway in the absence of COX-2.

INTERPRETATION

These experiments show that 5-LO negatively regulates fracture healing and that shunting of arachidonic acid into the 5-LO pathway may account, at least in part, for the impaired fracture healing response observed in COX-2(KO) mice.

Synthesis and biological evaluation of 3-[4-(amino/methylsulfonyl)phenyl]methylene-indolin-2-one derivatives as novel COX-1/2 and 5-LOX inhibitors

Fourteen new 3-[4-(amino/methylsulfonyl)phenyl]methylene-indolin-2-one derivatives were synthesized. Six compounds displayed potent inhibitory activities against COX-1/2 and 5-LOX with IC(50) in the range of 0.10-9.87 μM. Particularly, 10f exhibited well balanced inhibitory action on these enzymes (IC(50)=0.10-0.56 μM). More importantly, 10f and several other compounds had comparable or stronger anti-inflammatory and analgesic activities, but better gastric tolerability in vivo, as compared with darbufelone mesilate and tenidap sodium. Therefore, our findings may aid in the design of new and safe anti-inflammatory reagents for the intervention of painful inflammatory diseases, such as rheumatoid arthritis at clinic.

Efficacy and safety of flavocoxid, a novel therapeutic, compared with naproxen: a randomized multicenter controlled trial in subjects with osteoarthritis of the knee

INTRODUCTION

Flavocoxid is a novel flavonoid-based "dual inhibitor" of the 5-lipoxygenase (5-LOX) enzyme and the cyclooxygenase (COX) enzymes. This study was designed to compare the effectiveness and safety of flavocoxid to naproxen in subjects with moderate to severe osteoarthritis (OA) of the knee.

METHODS

In this randomized, multicenter, double-blind study, 220 subjects were assigned to receive either flavocoxid (500 mg twice daily) or naproxen (500 mg twice daily) for 12 weeks. The trial was structured to show noninferiority of flavocoxid to naproxen. Primary outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and subscales and a timed walk.

RESULTS

More than 90% of the subjects in both groups noted significant reduction in the signs and symptoms of knee OA. There were no statistically significant differences in efficacy between the flavocoxid and naproxen groups when the entire intent-to-treat population was analyzed. The flavocoxid group had significantly fewer upper gastrointestinal (UGI) and renal (edema) adverse events (AEs) as well as a strong trend toward fewer respiratory AEs.

CONCLUSION

Flavocoxid, a first-in-class flavonoid-based therapeutic that inhibits COX-1 and COX-2 as well as 5-LOX, was as effective as naproxen in managing the signs and symptoms of OA of the knee. Flavocoxid demonstrated better UGI, renal (edema), and respiratory safety profiles than naproxen.

Nonsteroidal antiinflammatory drug-related injury to the gastrointestinal tract: clinical picture, pathogenesis, and prevention

Increasing life expectancy in developed countries has led to a growing prevalence of arthritic disorders, which has been accompanied by increasing prescriptions for nonsteroidal antiinflammatory drugs (NSAIDs). These are the most widely used agents for musculoskeletal and arthritic conditions. Although NSAIDs are effective, their use is associated with a broad spectrum of adverse reactions in the liver, kidney, cardiovascular system, skin, and gut. Gastrointestinal (GI) side effects are the most common. The dilemma for the physician prescribing NSAIDs is, therefore, to maintain the antiinflammatory and analgesic benefits, while reducing or preventing GI side effects. The challenge is to develop safer NSAIDs by shifting from a focus on GI toxicity to the increasingly more appreciated cardiovascular toxicity.

Cost analysis of flavocoxid compared to naproxen for management of mild to moderate OA

OBJECTIVE

Flavocoxid is a medical food used for the clinical dietary management of osteoarthritis (OA). The acquisition cost of flavocoxid is higher than most traditional, generic NSAIDs. However, flavocoxid may have more favorable gastrointestinal (GI) toxicity resulting in lower overall costs. These costs have not been previously examined. This study provides a decision analytic model to assess the net costs of using flavocoxid for OA from a Medicare perspective.

RESEARCH DESIGN AND METHODS

A decision model was developed to estimate the total costs associated with flavocoxid versus naproxen for the management of Medicare patients with mild to moderate OA. Probabilities were obtained from literature and expert opinion, and costs were obtained from Medicare. Sensitivity analyses were conducted by varying probabilities and costs within clinically relevant ranges.

RESULTS

The base case resulted in flavocoxid having lower total annual costs ($1482 per patient) compared to naproxen ($1592). Flavocoxid remained the lowest cost option when the cost inputs were varied by 25% (above and below the base case), and when the probability of GI events with flavocoxid were varied by 25%. However, when GI rates from the literature and implied relative risks from the expert panel were used, or if the cost of PPIs was $0, then naproxen was the less costly alternative, though saving less than the annual cost of flavocoxid. Key limitations were the limited outcomes in the model (only GI events), lack of consideration of adherence or combination therapy, and the reliance on expert opinion due to a lack of data for flavocoxid.

CONCLUSIONS

In patients over 65 years of age who suffer from mild to moderate OA, flavocoxid may result in lower overall costs, despite a higher acquisition cost. Managed care organizations should consider total health care costs in the decision to include flavocoxid as a covered benefit.

Diclofenac: an update on its mechanism of action and safety profile

BACKGROUND

Diclofenac is a proven, commonly prescribed nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, anti-inflammatory, and antipyretic properties, and has been shown to be effective in treating a variety of acute and chronic pain and inflammatory conditions. As with all NSAIDs, diclofenac exerts its action via inhibition of prostaglandin synthesis by inhibiting cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) with relative equipotency. However, extensive research shows the pharmacologic activity of diclofenac goes beyond COX inhibition, and includes multimodal and, in some instances, novel mechanisms of action (MOA).

DATA SOURCES

Literature retrieval was performed through PubMed/MEDLINE (through May 2009) using combinations of the terms diclofenac, NSAID, mechanism of action, COX-1, COX-2, and pharmacology. Reference citations resulting from publications identified in the literature search were reviewed when appropriate.

METHODS

This article reviews the established, putative, and emerging MOAs of diclofenac; compares the drug's pharmacologic and pharmacodynamic properties with other NSAIDs to delineate its potentially unique qualities; hypothesizes why it has been chosen for further recent formulation enhancement; and evaluates the potential effect of its MOA characteristics on safety.

DISCUSSION

Research suggests diclofenac can inhibit the thromboxane-prostanoid receptor, affect arachidonic acid release and uptake, inhibit lipoxygenase enzymes, and activate the nitric oxide-cGMP antinociceptive pathway. Other novel MOAs may include the inhibition of substrate P, inhibition of peroxisome proliferator activated receptor gamma (PPARgamma), blockage of acid-sensing ion channels, alteration of interleukin-6 production, and inhibition of N-methyl-D-aspartate (NMDA) receptor hyperalgesia. The review was not designed to compare MOAs of diclofenac with other NSAIDs. Additionally, as the highlighted putative and emerging MOAs do not have clinical data to demonstrate that these models are correct, further research is necessary to ascertain if the proposed pathways will translate into clinical benefits. The diversity in diclofenac's MOA may suggest the potential for a relatively more favorable profile compared with other NSAIDs.

GOAL: multicenter, open-label, post-marketing study of flavocoxid, a novel dual pathway inhibitor anti-inflammatory agent of botanical origin

OBJECTIVES

GOAL (Gauging Osteoarthritis [OA] with Limbrel*), an open-label, post-marketing study was performed to determine the overall efficacy and gastrointestinal (GI) tolerability of flavocoxid, a novel, plant-based, anti-inflammatory medication, in a 'real world' clinical practice setting. To this end, the study enrolled several unique patient types including nonsteroidal anti-inflammatory drug (NSAID) naïve patients, those who had used NSAIDs in the past, regardless of outcome (positive or negative), and those who had previously taken a gastroprotective medication to improve GI tolerability or continued to take it as a precautionary measure to prevent NSAID-associated GI damage.

METHODS

A total of 1067 individuals at 41 rheumatology practices were enrolled and prescribed flavocoxid, 500 mg b.i.d., for 60 days. The Physician Global Assessment of Disease (PGAD) visual analog scale (VAS) was used as a global measure to assess the signs and symptoms of OA, including joint discomfort, functional stiffness, functional mobility and quality of life. In addition, overall tolerability and upper GI tolerability were assessed by individual questions scored on a 5-part Likert scale. The physicians also monitored any interruption in, or cessation of use of flavocoxid due to a GI issue as well as changes in the use of gastroprotective medications. Adverse event (AE) monitoring was also conducted.

RESULTS

Of the 1005 patients who completed all follow-up visits, physicians recorded an average improvement in VAS scores from 60.1 +/- 18.8 at baseline to 42.5 +/- 21.9 at 8 weeks (p < 0.001) in 65.8% of patients. The PGAD VAS noted the most significant improvement in those patients with moderate to severe OA (baseline VAS [0 = least severe, 100 = most severe]: 0-25 mm, -3.5 +/- 6.9; 26-50 mm, -10.1 +/- 17.0; 51-75 mm, -19.3 +/- 19.5; 76-100 mm, -29.6 +/- 23.6; p < 0.001) and in those patients who were historically non-responders to NSAIDs (40.3 +/- 21.1 vs. 66.3 +/- 17.7 at baseline; p < 0.001). Patients who had previously responded well to NSAIDs had VAS scores of 42.6 +/- 19.8 vs. 58.0 +/- 18.0 (p < 0.001) and NSAID naïve subjects showed improvement in VAS scores from 60.5 +/- 18.0 at baseline to 46.3 +/- 23.7 (p < 0.001). The study recorded a low incidence ( approximately 10%) of AEs reported to physicians and good overall tolerability to flavocoxid. Flavocoxid showed improved upper GI tolerability in almost 50% of previous NSAID users (p < 0.001) and reduced therapy interruption in approximately 90% of previous NSAID users with a history of GI-related therapy interruptions (p < 0.0001). Finally, the use of flavocoxid resulted in a >30% reduction in or cessation of the use of gastroprotective medications such as proton pump inhibitors (PPI) or histamine-2 receptor antagonists (H2s) in subjects (p < 0.001).

CONCLUSIONS

Within a 'real world' clinical rheumatology practice setting, flavocoxid demonstrated significant efficacy in the management of OA in multiple patient types and displayed significant potential for reducing the possibility of adverse GI side-effects and use of gastroprotective agents associated with more traditional OA medications. A limitation of this study was that it was open-label and not rigorously controlled. The large population may compensate for this lack of control.

Regulation of microsomal prostaglandin E2 synthase-1 and 5-lipoxygenase-activating protein/5-lipoxygenase by 4-hydroxynonenal in human osteoarthritic chondrocytes

INTRODUCTION

This study aimed to investigate whether hydroxynonenal (HNE) depletion is responsible for the switch from cyclooxygenase-2 (COX-2) and microsomal prostaglandin E2 synthase-1 (mPGES-1) to 5-lipoxygenase-activating protein (FLAP) and 5-lipoxygenase (5-LOX).

METHODS

For COX-2 and mPGES-1 studies, human osteoarthritic chondrocytes were stimulated at different incubation times (up to 24 hours) with a single or repetitive addition of 10 muM HNE to the cultures at 2-hour intervals, up to 14 hours. For 5-LOX and FLAP studies, cells were treated with a single addition of 10 muM HNE for 24 hours, 48 hours, and 72 hours in the presence or absence of naproxen (a nonspecific COX-2 inhibitor) or antibody anti-transforming growth factor-beta 1 (TGF-beta1). The protein levels of COX-2, mPGES-1 and early growth response factor-1 (Egr-1) transcription factor were evaluated by western blot, and those of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and TGF-beta1 were determined with commercial kits. The levels of mPGES-1, FLAP and 5-LOX mRNA were measured by real-time RT-PCR. Transient transfection was performed to determine promoter activities of mPGES-1 and 5-LOX.

RESULTS

Single addition of 10 muM HNE to cultured chondrocytes induced PGE2 release as well as COX-2 and mPGES-1 expression at the protein and mRNA levels, with a plateau reached respectively at 8 and 16 hours of incubation, followed by a subsequent decline. However, repeated treatments with HNE prevented the decline of COX-2 and mPGES-1 expression that occurred with a single aldehyde addition. HNE induced mPGES-1 promoter activity, possibly through transcription factor Egr-1 activation. After 48 hours, when COX-2 expression decreased, the LTB4 level rose through 5-LOX and FLAP upregulation. The addition of naproxen to cultured chondrocytes revealed that FLAP and 5-LOX regulation by HNE required PGE2 production. Furthermore, our data showed that HNE significantly induced TGF-beta1 production. The addition of anti-TGF-beta1 antibody reduced HNE-induced 5-LOX and FLAP expression by 40%, indicating the partial involvement of a TGF-beta1-dependent mechanism.

CONCLUSIONS

Our data demonstrate that the shunt to the FLAP and 5-LOX pathway in HNE-induced human osteoarthritic chondrocytes is attributed to COX-2 and mPGES-1 inhibition, probably due to HNE depletion. PGE2 and TGF-beta1 are suggested to be involved in this regulation.

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.

NSAID-induced antral ulcers are associated with distinct changes in mucosal gene expression

BACKGROUND

The basis for individual variation in gastroduodenal vulnerability to NSAIDs is not well understood.

AIM

To assess whether a gene expression signature is associated with susceptibility to gastroduodenal ulcerations.

METHODS

Twenty-five Helicobacter pylori negative adults were treated for 7 days with naproxen 500 mg b.d. Subjects underwent baseline and post-treatment endoscopy, during which biopsies were taken from antrum and duodenum. RNA extraction and cDNA synthesis were performed, followed by PCR of 23 genes relevant to mucosal injury and repair. Fold changes in gene expression were compared between subjects who developed ulcers and those who did not.

RESULTS

Compared with subjects who did not develop ulcers (n = 18), subjects who developed antral ulcers (n = 7) had significantly greater mucosal up-regulation of interleukin-8 [Fold change = 33.5 (S.E.M. = 18.5) vs. -7.7 (3.2)] and of cyclo-oxygenase-2 [2.3 (1.7) vs. -10.8 (2.2)]. Conversely, non-ulcer subjects had significantly greater up-regulation of toll-like receptor-4, cyclo-oxygenase-1 and hepatocyte growth factor [14.0 (2.2) vs. -0.8 (1.0), 9.8 (2.4) vs. 0.0 (0.7) and 8.2 (2.6) vs. -2.2 (0.3) respectively].

CONCLUSIONS

NSAID-induced antral ulcers are associated with a specific pattern of gastroduodenal mucosal gene expression. These patterns may provide an insight into the molecular basis of individual susceptibility to mucosal injury.