Pharmacological and biochemical demonstration of the role of cyclooxygenase 2 in inflammation and pain

Antinociceptive and antiedematogenic activities of fenofibrate, an agonist of PPAR alpha, and pioglitazone, an agonist of PPAR gamma

Peroxisome proliferator activated receptors (PPAR) are ligand-regulated transcription factors that control the expression of many genes. The antiinflammatory activity of fibrates, PPARalpha agonists, and thiazolidinediones, PPARgamma agonists, has been demonstrated in many in vitro and a few in vivo studies. In the present study, we evaluated the effect of acute (100 or 300 mg/kg, p.o.) or prolonged (100 or 300 mg/kg day, 7 days, p.o.) treatment with fenofibrate and acute treatment with pioglitazone (doses ranging from 1 to 50 mg/kg, i.p.), PPARalpha and PPARgamma agonists, respectively, on experimental models of nociception and edema, in order to expand the knowledge of their potential antiinflammatory activities. Fenofibrate and pioglitazone did not inhibit the nociceptive response in the hot-plate model and the first phase of formaldehyde induced nociceptive response in mice. However, treatment with pioglitazone and prolonged treatment with fenofibrate inhibited the second phase of this response. Mechanical allodynia induced by carrageenan in rats was inhibited by prolonged treatment with fenofibrate, but not by acute treatment with pioglitazone or fenofibrate. Both drugs inhibited paw edema induced by carrageenan in rats. Fenofibrate did not inhibit mechanical allodynia or paw edema induced by phorbol-12,13-didecanoate (PDD), a protein kinase C activator, in rats. Pioglitazone inhibited paw edema, but not mechanical allodynia, induced by PDD. The results represent the first demonstration of the antinociceptive and antiedematogenic activities of fenofibrate and pioglitazone and give further support to the potential use of PPAR agonists in the treatment of different inflammatory diseases.

Molecular mechanisms involved in the reciprocal regulation of cyclooxygenase and nitric oxide synthase enzymes

The nitric oxide (NO) and cyclooxygenase (COX) pathways share a number of similarities. NO is the mediator generated from the NO synthase (NOS) pathway and COX converts arachidonic acid to prostaglandins (PGs), prostacyclin, and thromboxane A2. Two major forms of NOS and COX have been identified to date. The constitutive isoforms of these enzymes play an important role in the regulation of several physiological states. On the other hand, in an inflammatory setting, the inducible isoforms of these enzymes are induced in a variety of cells resulting in the production of large amounts NO and PGs, which play pathological roles in several disease states. An important link between the NOS and COX pathways was made by our group when we demonstrated that NO activates the COX enzymes, an event leading to overt production of PGs, suggesting that COX enzymes represent important endogenous 'receptor' targets for modulating the multifaceted roles of NO. More importantly, mechanistic studies of how NO activates the COX enzymes have been undertaken and additional pathways through which NO modulates PG production unraveled. The purpose of this article is to cover the advances, which have occurred over the years and in particular to summarize experimental data that outline how the discovery that NO modulates PG production has impacted and extended our understanding of these two systems in physiopathological events.

Peripheral and central mechanisms of visceral sensitization in man

Visceral hypersensitivity (perception of gastrointestinal sensory events at a lower-than-normal threshold) is considered to be an important pathophysiological mechanism in the development of functional gastrointestinal disorders (FGIDs), such as irritable bowel syndrome, non-cardiac chest pain and functional dyspepsia. These disorders are associated with significant health care and socioeconomic costs due to factors such as repeated visits to consultants, hospitalizations and work absenteeism. Despite the presence of extensive evidence linking visceral hypersensitivity and FGIDs, the mechanism(s) underlying visceral hypersensitivity has not been fully elucidated. Suggested hypotheses include sensitization of afferent neurones, both at the level of the enteric and the (afferent) autonomic nervous system (peripheral sensitization), sensitization of spinal cord dorsal horn neurones (central sensitization) and psychosocial factors/psychiatric comorbidity influencing the processing of afferent signals at the level of the brain. Importantly, these hypotheses may be complementary rather than mutually exclusive. However, the degree to which each of these mechanisms contributes to the overall perception of visceral pain, and therefore the generation of symptoms, still remains unclear. This article discusses the mechanisms that may underlie visceral hypersensitivity, with reference to FGIDs. Understanding these mechanisms is essential in order to improve the diagnosis and treatment of patients with these disorders.

Effects of cyclooxygenase inhibition on the gastrointestinal tract

Cyclooxygenase (COX) is a rate-limiting enzyme that catalyzes the conversion of arachidonic acid, an essential fatty acid present in cell membrane phospholipids and liberated by phospholipase, into prostaglandins (PGs) and prostanoids. COX has two distinct membrane-anchored isoenzymes; COX-1 and COX-2. COX-1 is a constitutively expressed and found in most normal body tissues; COX-2 is expressed in normal tissues at low levels and is highly induced by pro-inflammatory mediators in the setting of inflammation, injury, and pain. Inhibitors of COX activity include: (1) conventional non-selective non-steroidal anti-inflammatory drugs (ns-NSAIDs); (2) selective COX-2 inhibitors (COXIBs); and (3) COX-1 inhibitors. Non-selective NSAIDs, at therapeutic doses, inhibit both COX-1 and COX-2. The anti-inflammatory benefits of these drugs are primarily derived from COX-2 inhibition, while inhibition of COX-1 often elicits gastrointestinal (GI) toxicity. Therefore, COXIBs were developed to provide a selective COX-2 agent, i.e., one, that at fully therapeutic doses demonstrated comparable therapeutic benefit to non-selective NSAIDs, without the attendant COX-1-mediated GI toxicities. In this review, we evaluate available literature describing the pathophysiologic role of cyclooxygenases and the effects of their inhibition in GI system in experimental and domestic animal species.

Contributions of cyclooxygenase-2 to neuroplasticity and neuropathology of the central nervous system

Cyclooxygenase (COX) enzymes, or prostaglandin-endoperoxide synthases (PTGS), are heme-containing bis-oxygenases that catalyze the first committed reaction in metabolism of arachidonic acid (AA) to the potent lipid mediators, prostanoids and thromboxanes. Two isozymes of COX enzymes (COX-1 and COX-2) have been identified to date. This review will focus specifically on the neurobiological and neuropathological consequences of AA metabolism via the COX-2 pathway and discuss the potential therapeutic benefit of COX-2 inhibition in the setting of neurological disease. However, given the controversy surrounding the use of COX-2 selective inhibitors with respect to cardiovascular health, it will be important to move beyond COX to identify which down-stream effectors are responsible for the deleterious and/or potentially protective effects of COX-2 activation in the setting of neurological disease. Important advances toward this goal are highlighted herein. Identification of unique effectors in AA metabolism could direct the development of new therapeutics holding significant promise for the prevention and treatment of neurological disorders.

Intrathecally administered COX-2 but not COX-1 or COX-3 inhibitors attenuate streptozotocin-induced mechanical hyperalgesia in rats

Members of the cyclooxygenase (COX) family are known to catalyze the rate-limiting steps of prostaglandins synthesis and reported to be involved in neuropathic pain. Diabetic neuropathy is a type of neuropathic pain, though it is not clear if COX is relevant to the condition. Recently, spinal COX-2 protein was found to be increasing in streptozotocin-induced rats as compared to the constitutive expression. We attempted to determine which cyclooxygenase isoforms are involved in streptozotocin-induced mechanical hyperalgesia, which was induced by a single intraperitoneal injection of 75 mg/kg of streptozotocin. Intrathecal administrations of the COX-2 inhibitors SC-58125 (7-100 microg) and NS-398 (7-60 microg), as well as a high dose (100 microg) of the COX-1 inhibitor SC-560 attenuated hyperalgesia, whereas intrathecal administrations of a low dose (10 microg) of SC-560 and the COX-3 inhibitor acetaminophen (1-7 mg) did not. Further, intrathecal administration of SC-58125 (100 microg) did not produce an analgesic effect in normal rats. These results indicate that intrathecal administration of COX-2 inhibitors has an anti-hyperalgesic effect on streptozotocin-induced mechanical hyperalgesia and we concluded that spinal COX-2 is pivotal in streptozotocin-induced hyperalgesia.

Effects of parecoxib on plasma protein extravasation and c-fos expression in the rat

OBJECTIVE

We aimed to investigate the effects of the cyclooxygenases-2 (COX-2) inhibitor parecoxib on meningeal plasma protein extravasation (PPE) and on c-fos expression in the nucleus trigeminalis caudalis in an animal model of trigeminovascular activation. Background.-Recent reports about the efficacy of COX-2 inhibitors in migraine treatment suggest the involvement of COX-2 in migraine pathophysiology. So far, studies on the role of COX-2 in animal models of migraine are lacking.

METHODS

Unilateral electrical stimulation of the trigeminal ganglion was performed in anesthetized male Sprague Dawley rats. We assessed PPE in the ipsilateral dura mater and expression of c-fos within the ipsilateral trigeminal nucleus caudalis (TNC) under control conditions and after pretreatment with parecoxib.

RESULTS

Parecoxib significantly attenuated PPE in the rat dura mater. The PPE ratio under control conditions (1.73 +/- 0.19 (mean +/- SD)) was reduced by 58.9 +/- 30% after pretreatment with 10 mg/kg parecoxib and by 78.1 +/- 23% after pretreatment with 50 mg/kg. c-fos experiments: Compared with vehicle, all doses of parecoxib (1 mg/kg, 10 mg/kg, 50 mg/kg) significantly reduced the number of c-fos positive cells in the ipsilateral TNC (P < .05). The number of c-fos positive cells in the ipsilateral TNC was 50 +/- 2.7 (mean +/- SEM) under control conditions and 9.1 +/- 0.6 after pretreatment with 50 mg/kg parecoxib.

CONCLUSION

Our study results suggest that COX-2 is involved in neurogenic inflammation of the rat dura mater. Moreover, the study points to a role of COX-2 inhibitors in trigeminal nociception at the second-order level.

Platelet-activating factor is crucial in psoralen and ultraviolet A-induced immune suppression, inflammation, and apoptosis

Psoralen plus UVA (PUVA) is used as a very effective treatment modality for various diseases, including psoriasis and cutaneous T-cell lymphoma. PUVA-induced immune suppression and/or apoptosis are thought to be responsible for the therapeutic action. However, the molecular mechanisms by which PUVA acts are not well understood. We have previously identified platelet-activating factor (PAF), a potent phospholipid mediator, as a crucial substance triggering ultraviolet B radiation-induced immune suppression. In this study, we used PAF receptor knockout mice, a selective PAF receptor antagonist, a COX-2 inhibitor (presumably blocking downstream effects of PAF), and PAF-like molecules to test the role of PAF receptor binding in PUVA treatment. We found that activation of the PAF pathway is crucial for PUVA-induced immune suppression (as measured by suppression of delayed type hypersensitivity to Candida albicans) and that it plays a role in skin inflammation and apoptosis. Downstream of PAF, interleukin-10 was involved in PUVA-induced immune suppression but not inflammation. Better understanding of PUVA's mechanisms may offer the opportunity to dissect the therapeutic from the detrimental (ie, carcinogenic) effects and/or to develop new drugs (eg, using the PAF pathway) that act like PUVA but have fewer side effects.

Expression of COX-2 and hsp72 in peritoneal macrophages after an acute ochratoxin A treatment in mice

Ochratoxin A (OTA) is a secondary fungal metabolite produced by Aspergillus and Penicillium strains that elicits a broad spectrum of toxicological effects in animals and man. A single oral OTA administration (10 mg/kg) in mice induced after 24 h oxidative damage and polymorphonuclear leukocyte (PMN) infiltration in parenchymal organs. In fact, OTA treatment increased lipid peroxidation (via malondialdehyde formation) in kidney and liver and PMN accumulation in duodenum, as shown by myeloperoxidase activity. Following in vivo OTA treatment an increase of cyclooxygenase-2 and of heat shock protein 72 expression was evidenced in peritoneal macrophage lysates by Western blot. That OTA modulates these proteins involved in the inflammatory process indicates that the mycotoxin is able to activate immune cells. This study suggests that the oxidative stress, the neutrophil accumulation in parenchymal tissues and the modulation of inflammatory parameters in peritoneal macrophages induced by OTA are involved in its toxicity, and represent early events related to several aspects of OTA mycotoxicosis.

Helicobacter pylori eradication therapy on histologic change in the distal esophagus

BACKGROUND

Although cases of reflux esophagitis (RE) developing after treatment to eradicate Helicobacter pylori have been discussed in some detail, no reports are available concerning the histologic examination of RE both before and after eradication therapy.

MATERIALS AND METHODS

Sixty-one patients and 111 specimens were investigated using endoscopic and histologic techniques. The histologic findings including basal zone height, papillar height, Ki-67 labeling index, and COX-2 expression before and after treatment for H. pylori infection were compared with those in normal controls and patients with endoscopic RE.

RESULTS

Twelve months after eradication therapy, the incidence of newly developed endoscopic RE was 20% (5/25). Basal zone height and papillar height had increased at 1 month, but had returned to pretreatment levels after 12 months of eradication therapy. The Ki-67 labeling index was significantly increased 1 and 12 months after eradication therapy compared to values before treatment. COX-2 expression gradually increased after the treatment. The phenomena linked to esophagitis appeared after eradication therapy. However, the severity and extent of these signs were not so high after the treatment of H. pylori than those in patients with overt reflux esophagitis. Focusing on the patients with hiatal hernia, papillar height and Ki-67 labeling index increased significantly after eradication therapy, values being almost the same as those in the patients with endoscopic RE.

CONCLUSIONS

Hiatal hernia plays an important role in the possible occurrence of hidden RE after treatment for a H. pylori infection.

Prostaglandins in Health and Disease: An Overview

OBJECTIVES

Prostaglandins are a group of biologically active compounds that play major roles in human physiology in both health and disease. They function in many different ways and in all major organs. This article reviews the basic physiology of prostaglandins and their application to specific effects on these systems in normal and abnormal clinical states. The critical therapeutic implications of the use of nonsteroidal antiinflammatory drugs in altering organ homeostasis are also examined.

METHODS

References were taken from Medline, Embase, and Index Medicus from 1966 to September 2005. A search was done with keywords, including prostaglandins, nonsteroidal antiinflammatory drugs, inflammation, arachidonic acid, Cox-1 (cyclooxygenase-1), and Cox-2 (cyclooxygenase-2).

RESULTS

There was a close correlation and predictability between basic prostaglandin physiology and the anticipated effects of these compounds on the heart, lungs, kidneys, gastrointestinal tract, bones and joints, brain, and male and female reproductive systems. These effects are organ and tissue specific. Despite these findings, unexplained and sometimes paradoxical physiologic responses were identified. A prime example of this is the role of prostaglandins in bone metabolism demonstrating both stimulatory and inhibitory effects. In addition all NSAIDs have the potential to impair the normal physiologic effects of prostaglandins depending primarily on the specific organ and the clinical setting.

CONCLUSIONS

Prostaglandins are regulatory compounds that play important roles in many physiologic processes in the human body. An understanding of the basic science of prostaglandins is valuable in anticipating the organ-specific biologic effects of these unique compounds in health and disease. However, at selected sites and under different physiologic conditions, unexplained and sometimes paradoxical effects are generated. Impairment of their regulatory functions can lead to significant short- or long-term organ dysfunction.

COX-1 inhibition enhances scratching behaviour in NC/Nga mice with atopic dermatitis

NC/Nga (NC) mice, spontaneously develop an eczematous atopic dermatitis (AD)-like skin lesion when kept under conventional condition (Conv), but not under specific pathogen-free (SPF) conditions, have been thought to be an animal model of AD. We have previously shown that PGD(2) and arachidonic acid inhibited the scratching behaviour of NC mice, while indomethacin enhanced it. This study was designed to assess the role of cyclooxygenase (COX)-1 and COX-2 in the itch-related scratching behaviour of NC mice. We examined the expression of COX in the skin using real-time PCR and Western blotting and the effects of SC-560 (a COX-1 selective inhibitor) or NS-398 (a COX-2 selective inhibitor) on scratching behaviour in relation to skin prostaglandin (PG) levels in NC mice. COX-1 mRNA expression was unchanged and protein expression decreased in Conv NC mice compared with that of SPF mice. By contrast, COX-2 mRNA and protein expression increased in Conv NC mice. SC-560 increased scratching behaviour and significantly reduced skin PGD(2), PGE(2) and PGF(2alpha) levels, but NS-398 did not have effects on scratching and skin PG level. Moreover, the topical application of PGD(2), which might be the endogenous inhibitor of itching, suppressed the SC-560-induced enhancement of scratching behaviour by NC mice. These results suggest COX-1-coupled skin PGD(2) biosynthesis plays a physiological role in inhibiting regulation of pruritus in NC mice with AD.

Cyclooxygenase-2 inhibitor, celecoxib, inhibits the altered hippocampal neurogenesis with attenuation of spontaneous recurrent seizures following pilocarpine-induced status epilepticus

Recent evidences suggest key roles of abnormal neurogenesis and astrogliosis in the pathogenesis of epilepsy. Alterations in the microenvironment of the stem cell, such as microglial activation and cyclooxygenase-2 induction may cause ectopic neurogenesis or astrogliosis. Here, we examined if inflammatory blockade with celecoxib, a selective cyclooxygenase-2 inhibitor, could modulate the altered microenvironment in the epileptic rat brain. Celecoxib attenuated the likelihood of developing spontaneous recurrent seizures after pilocarpine-induced prolonged seizure. During the latent period, celecoxib prevented neuronal death and microglia activation in the hilus and CA1 and inhibited the generation of ectopic granule cells in the hilus and new glia in CA1. The direct inhibition of precursor cells by celecoxib was further demonstrated in human neural stem cells culture. These findings raise the evidence of COX-2 induction to act importantly on epileptogenesis and suggest a potential therapeutic role for COX-2 inhibitors in chronic epilepsy.

Vitamin A active metabolite, all-trans retinoic acid, induces spinal cord sensitization. I. Effects after oral administration

BACKGROUND AND PURPOSE

Retinoic acid is an active metabolite of vitamin A involved in the modulation of the inflammatory and nociceptive responses. The aim of the present study was to analyze the properties of spinal cord neuronal responses of male Wistar rats treated with all-trans retinoic acid (ATRA) p.o. in the normal situation and under carrageenan-induced inflammation. We also studied the expression and distribution of cyclooxygenases (COX) in the spinal cord.

EXPERIMENTAL APPROACH

Properties of spinal cord neurons were studied by means of the single motor unit technique. The expression of COX enzymes in the spinal cord was assessed by Western blot analysis and immunohistochemistry.

KEY RESULTS

Intensity thresholds for mechanical and electrical stimulation (C-fibers) were significantly lower in animals treated with ATRA than vehicle, either in normal rats or in rats with inflammation. The size of cutaneous receptive fields was also larger in animals treated with ATRA in the normal and inflammatory conditions. The expression of COX-2 enzyme, but not COX-1, was significantly higher in animals treated with ATRA. COX-2 labeling was observed in dorsal horn cells and in ventral horn motoneurons.

CONCLUSIONS AND IMPLICATIONS

In conclusion, the oral treatment with ATRA in rats induces a sensitization-like effect on spinal cord neuronal responses similar to that observed in animals with inflammation and might explain the enhancement of allodynia and hyperalgesia observed in previously published behavioral experiments. The mechanism of action involves an over-expression of COX-2, but not COX-1, in dorsal and ventral horn areas of the lumbar spinal cord.

Differential expression and regulation of cylooxygenases, prostaglandin E synthases and prostacyclin synthase in rat uterus during the peri-implantation period

It has been shown that both prostaglandin I2 (PGI2) and PGE2 are essential for mouse implantation, whereas only PGE2 is required for hamster implantation. To date, the expression and regulation of cyclooxygenase (COX) and prostaglandin E synthase (PGES), which are responsible for PGE2 production, have not been reported in the rat. The aim of this study was to examine the expression pattern and regulation of COX-1, COX-2, membrane-associated PGES-1 (mPGES-1), mPGES-2 and cytosolic PGES (cPGES) in rat uterus during early pregnancy and pseudopregnancy, and under delayed implantation. At implantation site on day 6 of pregnancy, COX-1 immunostaining was highly visible in the luminal epithelium, and COX-2 immunostaining was clearly observed in the subluminal stroma. Both mPGES-1 mRNA and protein were only observed in the subluminal stroma surrounding the implanting blastocyst at the implantation site on day 6 of pregancy , but were not seen in the inter-implantation site on day 6 of pregnancy and on day 6 of pseudopregnancy. Our data suggest that the presence of an active blastocyst is required for mPGES-1 expression at the implantation site. When pregnant rats on day 5 were treated with nimesulide for 24 h, mPGES-1 protein expression was completely inhibited. cPGES immunostaining was clearly observed in the luminal epithelium and subluminal stromal cells immediately surrounding the implanting blastocyst on day 6 of pregnancy. mPGES-2 immunostaining was clearly seen in the luminal epithelium at the implantation site. Additionally, immunostaining for prostaglandin I synthase (PGIS) was also strongly detected at the implantation site. In conclusion, our results indicate that PGE2 and PGI2 should have a very important role in rat implantation.

Enhanced in vitro percutaneous absorption and in vivo anti-inflammatory effect of a selective cyclooxygenase inhibitor using microemulsion

Celecoxib, a specific COX-2 inhibitor, was recently approved for the treatment of rheumatoid and osteoarthritis, acute pain, familial adenomatous polyposis and primary dysmenorrhea. Oral administration of celecoxib is effective against ultraviolet B radiation (UVB)-induced skin carcinogenesis; however, its clinical use is restricted because of its failure to block the characteristic cutaneous inflammatory response and lower availability at the site of inflammation. Topical application of celecoxib has been effective compared with oral in certain clinical conditions. The present study was undertaken to develop and investigate the development of microemulsion system (isopropyl myristate/medium-chain glyceride/polysorbate 80/water) for topical delivery of celecoxib. The pseudoternary phase diagram was constructed with constant surfactant concentration, and several compositions were identified and characterized by using dynamic light scattering. The in vitro permeation rate of celecoxib through rat skin was determined for microemulsions, microemulsion gel, and cream by using the modified Franz-type diffusion cell. In all formulations tested, celecoxib permeated more quickly, and the microemulsions increased the permeation rate of celecoxib up to 5 and 11 times compared with those of microemulsion gel and cream, respectively. Increasing the concentration of medium-chain mono-/di-glyceride in microemulsion imparted increased droplet size and viscosity and decreased diffusion coefficient. In vivo anti-inflammatory study suggested that the developed microemulsion formulations might serve as potential drug vehicle for the prevention of UVB-induced skin cancer.

Comparative immunoproteomics of identification and characterization of virulence factors from Helicobacter pylori related to gastric cancer

Helicobacter pylori is an important risk factor of gastric cancer (GC). Although many H. pylori virulence factors have been reported, the pathogenic mechanism by which H. pylori infection causes GC remains unclear. The aims of this study were to identify GC-related antigens from H. pylori and characterize their roles in the development of GC. As GC and duodenal ulcer (DU) are considered clinically divergent, we compared two-dimensional immunoblots of an acid-glycine extract of H. pylori probed with serum samples from 15 patients with GC and 15 with DU to find GC-related antigens, which were subsequently identified by mass spectrometry. Many protein spots were recognized by more than one serum, and 24 of these were better recognized by GC sera. The proteins showing higher frequency of recognition in GC group are threonine synthase, rod shape-determining protein, S-adenosylmethionine synthetase, peptide chain release factor 1, DNA-directed RNA polymerase alpha subunit, co-chaperonin GroES (monomeric and dimeric forms), response regulator OmpR, and membrane fusion protein. Of these proteins, GroES was identified as a dominant GC-related antigen with a much higher seropositivity of GC samples (64.2%, n = 95) compared with 30.9% for gastritis (n = 94) and 35.5% for DU (n = 124). GroES seropositivity was more commonly associated with antral GC than with non-antral GC (odds ratio = 2.7; 95% confidence interval, 1.1-6.7). In peripheral blood mononuclear cells, GroES stimulated production of interleukin (IL)-8, IL-6, granulocyte macrophage colony-stimulating factor, IL-1beta, tumor necrosis factor-alpha, cyclooxygenase-2, and prostaglandin E(2). Moreover when incubated with gastric epithelial cells, GroES induced expression of IL-8, cell proliferation, and up-regulation of c-jun, c-fos, and cyclin D1 but caused down-regulation of p27(Kip1). We conclude that GroES of H. pylori is a novel GC-associated virulence factor and may contribute to gastric carcinogenesis via induction of inflammation and promotion of cell proliferation.

Pharmacological separation between peripheral and central functions of cyclooxygenase-2 with CIAA, a novel cyclooxygenase-2 inhibitor

There are many reports concerning the physiological and pathological involvement of cyclooxygenase (COX)-2 in the central nervous system and peripheral tissue cells. Selective COX-2 inhibitors that mainly distribute peripherally have not been reported thus far. Therefore central and peripheral roles of COX-2 remain classified pharmacologically. In this study, in vivo pharmacological profiles of CIAA ([6-chloro-2-(4-chlorobenzoyl)-1H-indol-3-yl]acetic acid), a novel selective COX-2 inhibitor which distributes at higher concentrations in plasma than in brain, were compared with those of well-known selective COX-2 inhibitors, celecoxib and rofecoxib. Additionally, the possibility of pharmacological separation between peripheral and central actions of COX-2 with the inhibitors was investigated. CIAA selectively inhibited COX-2 activity compared with COX-1 in in vitro assays with rat whole blood. The compound exhibited lower brain penetration and higher plasma concentration (the brain/plasma concentration ratio was approximately 0.02) than celecoxib and rofecoxib after oral administration. Therefore, CIAA is mainly expected to act peripherally. Edema and prostaglandin E2 (PGE2) production in Carrageenan-injected rat paws, and pyrexia and PGE2 production in the brain in lipopolysaccharide (LPS)-injected rats were measured in in vivo experiments. CIAA exhibited lower ratios of anti-pyretic/anti-edematous activities and of inhibitory activities of PGE2 production in brain/paw than those of celecoxib and rofecoxib, and these ratios well-reflected brain/plasma concentration ratios. In conclusion, we discovered a novel selective COX-2 inhibitor, CIAA, which distributes at higher concentrations in plasma than in brain, which would make possible the pharmacological separation of the peripheral and central functions of COX-2.

NSAIDs and Alzheimer disease: epidemiological, animal model and clinical studies

This review reports correlations between four independent fields related to inflammation and Alzheimer disease: fundamental pathology, epidemiology, transgenic animal studies and clinical trials. Activated microglia, along with a spectrum of inflammatory mediators, have been identified in association with the lesions of Alzheimer disease (AD), suggesting that antiinflammatory agents such as NSAIDs should protect against the disease. In multiple epidemiological investigations testing this hypothesis, a significant risk reduction, or a trend towards such a reduction has been observed in long term as opposed to short term users of traditional NSAIDs. In studies where such NSAIDs have been administered to AD transgenic mice, a dose dependent reduction in pathology was observed. The selective C0X-2 inhibitors were ineffective. Results of clinical investigations have so far been disappointing but have nevertheless correlated with fundamental pathological findings and with transgenic mouse results. Four clinical trials using selective COX-2 inhibitors failed which is in keeping with the animal results and is consistent with pathological findings demonstrating that COX-1 and not COX-2 is the appropriate target in activated human microglia. A low dose trial of the traditional NSAID naproxen also failed, but pilot trials using therapeutically established doses of indomethacin and diclofenac/misoprostol showed promise. Further clinical investigations with relatively high doses of traditional NSAIDs might be warranted, although significant side effects should be anticipated.

Effects of three purgative decoctions on inflammatory mediators

In traditional Chinese medicine (TCM), there are three Cheng-Chi-Tang decoctions (CCTDs) including: Ta-Cheng-Chi-Tang (TCCT), Xiao-Chen-Chi-Tang (XCCT) and Tiao-Wei-Chen-Chi-Tang (TWCCT), which are the frequently used purgative remedies to treat "internal heat"-induced symptoms like a bloated and painful abdomen, hard stools and fever, etc. Constituents in each formulation are Rheum palmatum L. (Polygonaceae), Magnolia officinalis Rehd. et Wils. (Magnoliaceae), Citrus aurantium L. (Rutaceae), Mirabilitum (mirabilite, crystals of sodium sulfate, Na2SO4) for TCCT; Rheum palmatum, Magnolia officinalis, Citrus aurantium for XCCT; and Rheum palmatum, Mirabilitum, Glycyrrhiza uralensis Fisch. (Leguminosae) for TWCCT. However, the underlying mechanisms for purging internal pathological heat are far from fully clarified, and few scientific investigations have been carried out to delineate the relationships between the anti-inflammatory effects and laxative potencies of these formulations. In this study, the anti-inflammatory effects of the three CCTDs on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E (PGE2) production in RAW 264.7 cells, carrageenan-induced paw edema in mice and the laxative effect in mice were explored. The results showed that TCCT inhibited LPS-induced NO and PGE2 production and inducible nitric oxide synthase (iNOS) expression in RAW 264.7 cells more effectively than did XCCT or TWCCT. Moreover, paw edema of carrageenan-treated mice was significantly attenuated in mice pretreated with 1 g/kg TCCT. TCCT also showed the strongest purgative activity among the three formulations. These findings indicate that TCCT has anti-inflammatory effects in addition to its traditionally known purgative activities. It may have potential to treat inflammatory disease conditions.

A computational protocol for the integration of the monotopic protein prostaglandin H2 synthase into a phospholipid bilayer

Prostaglandin H2 synthase (PGHS) synthesizes PGH2, a prostaglandin precursor, from arachidonic acid and was the first monotopic enzyme to have its structure experimentally determined. Both isozymes of PGHS are inhibited by nonsteroidal antiinflammatory drugs, an important class of drugs that are the primary means of relieving pain and inflammation. Selectively inhibiting the second isozyme, PGHS-2, minimizes the gastrointestinal side-effects. This had been achieved by the new PGHS-2 selective NSAIDs (i.e., COX-2 inhibitors) but it has been recently suggested that they suffer from additional side-effects. The design of these drugs only made use of static structures from x-ray crystallographic experiments. Investigating the dynamics of both PGHS-1 and PGHS-2 using classical molecular dynamics is expected to generate new insight into the differences in behavior between the isozymes, and therefore may allow improved PGHS-2 selective inhibitors to be designed. We describe a molecular dynamics protocol that integrates PGHS monomers into phospholipid bilayers, thereby producing in silico atomistic models of the PGHS system. Our protocol exploits the vacuum created beneath the protein when several lipids are removed from the top leaflet of the bilayer. The protein integrates into the bilayer during the first 5 ns in a repeatable process. The integrated PGHS monomer is stable and forms multiple hydrogen bonds between the phosphate groups of the lipids and conserved basic residues (Arg, Lys) on the protein. These interactions stabilize the system and are similar to interactions observed for transmembrane proteins.

Cyclooxygenase isozymes are expressed in human myeloma cells but not involved in anti-proliferative effect of cyclooxygenase inhibitors

Considering possible tumorigenic activity of cyclooxygenase (COX) isozymes in myeloma, we examined expression levels of COX-1 and -2 in seven human myeloma cell lines (ARH-77, IM-9, RPMI-8226, HPC, HS-Sultan, TSPC-1, and U-266). As analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR), all the cell lines constitutively expressed COX-1, while COX-2 levels markedly varied among different cell lines. Induction of COX-2 by phorbol ester was observed in RPMI-8226 and HPC cells. In contrast, COX-2 was constitutively expressed in ARH-77 and IM-9 cells. Moreover, the high expression level of COX-2 protein in ARH-77 cells was verified by Western blotting. Intact cells of ARH-77 converted 14C-labeled arachidonic acid to prostaglandin E2, F2alpha, and D2, and this activity was dose-dependently inhibited by selective COX-2 inhibitors (SC-58125 and NS-398), a non-selective COX inhibitor (indomethacin), and relatively high concentrations of a selective COX-1 inhibitor (SC-560). These COX inhibitors also suppressed the proliferation of ARH-77 cells, but significant suppression was seen only at 100 microM, a much higher concentration than those sufficient for the COX inhibition. Moreover, proliferation of the myeloma cells lacking COX-2 was also suppressed by 100 microM of SC-58125. These results suggested that the anti-proliferative effect of the COX inhibitors is independent of the inhibition of COX-2.

Plant originated glycoprotein has anti-oxidative and anti-inflammatory effects on dextran sulfate sodium-induced colitis in mouse

We investigated the preventive effect of glycoprotein (27 kDa) isolated from Gardenia jasminoides Ellis (GJE) fruits on colitis in dextran sulfate sodium (DSS, 3%)-induced A/J mice which were administrated orally for 7 days. Anti-inflammatory activity of GJE glycoprotein was assessed by neutrophil infiltration and colonic lipid peroxidation, and determined by myeloperoxidase (MPO) activity and levels of thiobarbituric acid reactive substances (TBARS), respectively in DSS treatment system. The activities of antioxidative enzymes [catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx)], activation of inflammation related mediators (iNOS, COX-2, and NF-kappaB), and production of nitric oxide (NO) and reactive oxygen species (ROS) were also measured. The results of this study showed that GJE glycoprotein (80 microg/ml) has a scavenging property to inhibit the intracellular ROS production in RAW 264.7 cells and that GJE glycoprotein (80 mg/kg BW) significantly suppressed the increase in the MPO activity, TBARS level, and NO production, inflammation related mediators [iNOS, COX-2, and NF-kappaB (p50)] activity in DSS-induced mice. Interestingly, the activities of CAT, SOD, and GPx were gradually augmented after a supplement of GJE glycoprotein. Therefore, we suggest that GJE glycoprotein is preventive and therapeutic agent for the ulcerative colitis.

COX-2 has a critical role during incorporation of structural bone allografts

Nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit cyclooxygenase (COX) activity, reduced pain and are commonly used in patients with skeletal injury. In this article we will also present data to show that selective COX-2 inhibitor delays allograft healing and incorporation. In contrast, local delivery of prostaglandin E2 (PGE2) enhanced bone formation at cortical bone graft junction. A 4-mm mid-diaphyseal segmental femoral defect was created and then repaired by frozen bone allograft of the same size. A 22-gauge metal pin was placed in the intramedullary cavity to stabilize the bone graft. Healing was evaluated weekly by X ray and by a semiquantitative histomorphometric analysis at 5 weeks postsurgery. Celecoxib (25 mg/kg/day) and Ketorolac (4 mg/kg/day) were administered daily for 2 weeks or 5 weeks. PGE2 was infused locally at a dose of 800 nmol/kg per day via osmotic minipump for 4 weeks. Inhibition of cyclooxygenase by daily administration of the Celecoxib or Ketorolac for 5 weeks reduced new bone ingrowth by about 60% (P < 0.05). The percentage of bony bridging in both drug-treated groups was significantly decreased at 5 weeks. Temporal administration of Celecoxib for 2 weeks also significantly reduced bone formation by 45% and withdrawal of the Celecoxib only led to slight recovery of bone formation at the graft side. In contrast to the inhibitory effects of NSAIDS, PGE2 infusion at the cortical bone junction increased bone formation by about twofold. These results demonstrated that COX-2 is essential for bone allograft incorporation. Furthermore, our data support the notion that COX-2-dependent PGE2 produced at the early stage of bone healing is prerequisite for efficient skeletal repair.

The cyclin-dependent kinase 2 inhibitor down-regulates interleukin-1beta-mediated induction of cyclooxygenase-2 expression in human lung carcinoma cells

Overexpression of cyclooxygenase-2 (COX-2) is frequently observed in several human cancers, including lung, colon, and head and neck. Malignancies are also associated with the dysregulation of cell cycle events and concomitant elevated activity of cyclin-dependent kinases (CDK). CDK2 is a key cell cycle regulatory protein that controls the transition of cells from G(1) to S phase. In this study, we furnish several lines of evidence that show a functional role for the CDK2 in interleukin-1beta (IL-1beta)-induced COX-2 expression in H358 human non-small cell lung carcinoma cell line by blocking CDK2 activity. First, we show that BMS-387032, a potent CDK2 inhibitor, blocks IL-1beta-induced expression as well as steady-state mRNA levels of COX-2. Second, we show that small interfering RNA that abrogates CDK2 expression also blocks IL-1beta-induced COX-2 expression. Third, results from in vitro kinase assays clearly show that IL-1beta induces CDK2 activity in H358 cells and this activity is significantly inhibited by BMS-387032. Moreover, CDK2 inhibition blocks IL-1beta-induced binding to the NF-IL6 element of the COX-2 promoter and inhibits transcription of the COX-2 gene. We also observed that BMS-387032 does not inhibit endogenous expression of COX-2 or prostaglandin synthesis in lung carcinoma cells. Finally, we provide evidence showing that IL-1beta-induced signaling events, such as p38 mitogen-activated protein kinase, phosphorylated stress-activated protein kinase/c-Jun NH(2)-terminal kinase, phosphorylated AKT, and phosphorylated extracellular signal-regulated kinase 1/2, are not inhibited by CDK2 inhibitor. Taken together, the data suggest that CDK2 activity may play an important event in the IL-1beta-induced COX-2 expression and prostaglandin E(2) synthesis and might represent a novel target for BMS-387032.

Anti-asthmatic activity of an ethanol extract from Saururus chinensis

As an attempt to find bioactive medicinal herbs exerting anti-asthmatic activity, the effects of an ethanol extract from the parts of Saururus chinensis were evaluated in both in vitro and in vivo. The ethanol extract of S. chinensis (ESC) inhibited generation of the cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D(2) in bone marrow-derived mast cells in a concentration-dependent manner with an IC(50) value of 14.3 microg/ml. ESC also inhibited leukotriene C(4) production with an IC(50) value of 0.3 microg/ml. This demonstrates that ESC has COX-2/5-lipoxygenase dual inhibitory activity. In addition, this compound inhibited degranulation reaction in a dose dependent manner, with an IC(50) value of 1.3 microg/ml. An ovalbumin induced mouse asthmatic animal model was used to determine its in vivo anti-asthmatic activity. The oral administration (50-200 mg/kg) of ESC reduced the number of infiltrated eosinophil in a bronchoalveolar lavage fluid. Furthermore, ESC (100 mg/kg) inhibited the eotaxin and IL-4 mRNA expression levels. These results suggest that the anti-asthmatic activity of S. chinensis might in part occur via the inhibition of eicosanoid generation, degranulation as well as the down regulation of IL-4 and eotaxin mRNA expression.

Accelerative effect of a selective cyclooxygenase-2 inhibitor on Fas-mediated apoptosis in human neutrophils

Inflammatory stimuli, such as cytokines, can induce cyclooxygenase-2 (COX-2) expression in neutrophils. Selective, anti-inflammatory COX-2 inhibitors have been developed for patients with acute inflammatory diseases. Recent work has shown that selective COX-2 inhibitors interfere with tumor cell growth. The purpose of this study was to examine the capability of selective COX-2 inhibitors on Fas-mediated apoptosis in cytokine-stimulated neutrophils. Tumor necrosis factor-alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced prostaglandin E2 (PGE2) release through the induction of COX-2 in neutrophils. This effect was not seen with either interleukin (IL)-1beta or IL-8. TNF-alpha-and GM-CSF-induced PGE2 release was blocked by the addition of the selective COX-2 inhibitor, N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulfonamide (NS-398; 1 microM). GM-CSF, IL-1beta and IL-8 suppressed Fas-mediated apoptosis in neutrophils; however, this effect was not seen with TNF-alpha. The anti-apoptotic effect of cytokines on Fas-mediated neutrophil apoptosis was attenuated by the addition of NS-398 (100 microM). These results suggest that NS-398 operates via two distinct mechanisms for regulating apoptosis and COX-2 activation in neutrophils. This distinction is indicated by the difference in concentration of NS-398 required for acceleration of Fas-mediated neutrophil apoptosis, and the inhibition of PGE2 synthesis. Moreover, NS-398 suppressed the anti-apoptotic activity of IL-8 and IL-1beta, but did not induce COX-2; therefore, the pro-apoptotic mechanism of the selective COX-2 inhibitor may be unrelated to COX-2 activity. Thus, a selective COX-2 inhibitor may contribute to the reduction of acute inflammation through the enhancement of neutrophil apoptosis.

Orthodontic tooth movement after inhibition of cyclooxygenase-2

INTRODUCTION

The purpose of this study was to compare the effects of a conventional nonsteroidal anti-inflammatory drug, diclofenac (Voltaren [Novartis, Barcelona, Spain]), and a specific cyclooxygenase-2 (COX-2) inhibitor, rofecoxib (Vioxx [MSD, Madrid, Spain]), on the inhibition of dental movement induced with a coil-spring orthodontic apparatus in rats.

METHODS

Tooth movement was measured on the lateral cranial teleradiographs of 42 male Wistar rats in 6 experimental groups: (1) 50-g coil spring and 2 rofecoxib injections of 1 mg per kilogram of body weight; (2) similar orthodontic procedure and 2 diclofenac injections of 10 mg per kilogram of body weight; (3) the same orthodontic treatment and 0.9% saline-solution injections; and (4), (5), and (6) 100-g coil appliance and the same pharmacological treatment as 1, 2, and 3, respectively.

RESULTS

The difference in tooth movement, measured in the control animals after 10 days of 50 or 100 g of orthodontic force application, was not statistically significant. Reduction in tooth movement in 50-g traction groups reached statistically significant differences; both rofecoxib or diclofenac were effective in inhibiting dental movement. The comparison of the 3 groups treated with 100 g of force also reached statistical significance. Both rofecoxib and diclofenac significantly inhibited dental movement, partially in the case of rofecoxib and totally in the case of diclofenac. Nevertheless, no statistically significant difference was found between the effects of rofecoxib and diclofenac.

CONCLUSIONS

There is no substantial advantage in using selective COX-2 inhibitors compared with nonspecific COX inhibitors to avoid interference with tooth movement during orthodontic treatment in rats.

Cyclooxygenase-2 inhibitors: what went wrong?

PURPOSE OF REVIEW

This review describes the biology underpinning the development of selective cyclooxygenase-2 inhibitors, documenting the clinical experience from the pivotal gastrointestinal safety trials to their eventual withdrawal or labelling with cardiovascular safety warnings.

RECENT FINDINGS

The elucidation of differences between the active sites of cyclooxygenase-1 and cyclooxygenase-2 allowed the targeted design of the selective cyclooxygenase-2 inhibitors known as coxibs. These were developed and marketed as non-steroidal anti-inflammatory drugs (NSAIDs) that had improved upper gastrointestinal safety compared with older non-selective NSAIDs. A large-scale study with arthritis patients to evaluate upper gastrointestinal safety, however, demonstrated that celecoxib was not superior in terms of upper gastrointestinal safety compared with the older non-selective NSAIDs that were used as comparators. In an equally large study with arthritis patients, a more selective cyclooxygenase-2 inhibitor, rofecoxib, did have improved upper gastrointestinal safety compared with the non-selective non-steroidal anti-inflammatory drug naproxen. Although concomitant clinical trial evidence emerged that rofecoxib increased cardiovascular risk, this was discounted by its pharmaceutical company owner. Despite the lack of improved upper gastrointestinal safety with celecoxib and the evidence of cardiovascular risk with rofecoxib, both agents had widespread clinical use for 4-5 years. This was not diminished by the publication of plausible eicosanoid-based biological mechanisms whereby selective cyclooxygenase-2 inhibition could increase cardiovascular risk. Finally, clinical trials involving patients with colorectal cancer and post-operative pain revealed increased cardiovascular risk with all members of this class of drug.

SUMMARY

These events provide a case study of a failure of the medical journal literature to guide drug usage.

Indomethacin and celecoxib impair rotator cuff tendon-to-bone healing

BACKGROUND

Nonsteroidal anti-inflammatory drugs are commonly prescribed after rotator cuff repair. These agents can impair bone formation, but no studies have evaluated their impact on tendon-to-bone healing.

HYPOTHESIS

Traditional nonselective nonsteroidal anti-inflammatory drugs and cyclooxygenase-2-specific nonsteroidal anti-inflammatory drugs interfere with tendon-to-bone healing.

STUDY DESIGN

Controlled laboratory study.

METHODS

One hundred eighty Sprague-Dawley rats underwent acute rotator cuff repairs. Postoperatively, 60 rats received 14 days of celecoxib, a cyclooxygenase-2-specific nonsteroidal anti-inflammatory drug; 60 received indomethacin, a traditional nonselective nonsteroidal anti-inflammatory drug; and 60 received standard rat chow. Animals were sacrificed at 2, 4, and 8 weeks and evaluated by gross inspection, biomechanical testing, histologic analysis, and polarized light microscopy to quantify collagen formation and maturation.

RESULTS

Five tendons completely failed to heal (4 celecoxib, 1 indomethacin). There were significantly lower failure loads in the celecoxib and indomethacin groups compared with the control groups at 2, 4, and 8 weeks (P < .001), with no significant difference between nonsteroidal anti-inflammatory drug groups. There were significant differences in collagen organization and maturation between the controls and both nonsteroidal anti-inflammatory drug groups at 4 and 8 weeks (P < .001). Controls demonstrated progressively increasing collagen organization during the course of the study (P < .001), whereas the nonsteroidal anti-inflammatory drug groups did not.

CONCLUSION

Traditional and cyclooxygenase-2-specific nonsteroidal anti-inflammatory drugs significantly inhibited tendon-to-bone healing. This inhibition appears linked to cyclooxygenase-2.

CLINICAL RELEVANCE

If the results of this study are verified in a larger animal model, the common practice of administering non-steroidal anti-inflammatory drugs after rotator cuff repair should be reconsidered.

Constitutive and activation-inducible cyclooxygenase-2 expression enhances survival of chronic lymphocytic leukemia B cells

We recently reported that activated normal human B lymphocytes express Cox-2. These findings prompted us to evaluate whether human B-CLL cells express Cox-2 and synthesize prostaglandins. In contrast to naive human B cells, B-CLL cells constitutively expressed Cox-2 protein and produced PGE2, PGF2alpha, and TXA2. Elevated Cox-2 expression was seen in a subgroup of B-CLL cells that exhibit poor prognostic factors, including unmutated variable heavy chain status and increased CD38 expression. Furthermore, stimulation of B-CLL cells with CD40 ligand plus TNFalpha increased Cox-2 levels. The role of Cox-2 in promoting B-CLL survival was investigated using nonselective and selective Cox-2 inhibitors. Significant reductions in B-CLL survival occurred following Cox-2 inhibition. These new findings support that constitutive Cox-2 expression in B-CLL cells promotes their survival and possibly their expansion in vivo. It will therefore be important to evaluate drugs that inhibit Cox-2 as potential therapeutic agents in B-CLL in vivo.

Prostaglandin-H-synthase (PGHS)-1 and -2 microtiter assays for the testing of herbal drugs and in vitro inhibition of PGHS-isoenzyms by polyunsaturated fatty acids from Platycodi radix

In order to test inhibition of prostaglandin-H-synthase-1 and -2 (PGHS-1 and -2) by plant extracts, we have established two enzyme based in vitro assays with enzyme immunoassay (EIA) evaluation. The assays have been evaluated with known synthetic inhibitors and with plant extracts. In a screening of traditionally used Chinese herbs for anti-inflammatory activity, a series of n-hexane and dichloromethane extracts showed significant inhibitory effect in comparison with the known specific PGHS-2 inhibitors NS-398 (IC(50) = 2.6 microM) and nimesulide (IC(50) = 36 microM). The lipophilic extracts of the Chinese drug Jiengeng, the dried roots of Platycodon grandiflorum (Jacq.) A. DC. (Campanulaceae), showed good inhibitory activity against both PGHS isoenzymes. The directly prepared DCM-extract exhibited better activity against PGHS-2 (IC(50) = 4.0 microg/ml) than against PGHS-1 (IC(50) = 17.6 microg/ml). We identified fatty acids as main active constituents and quantified them. Linoleic acid showed the highest content (ca. 20% of the dried extract) and a high and preferential PGHS-2 inhibitory activity (IC(50) (PGHS-1) = 20 microM; IC(50) (PGHS-2) = 2 microM). The comparison of the concentration of linoleic acid and the inhibitory activity of the direct DCM-extract showed, that linoleic acid is mainly responsible for the in vitro activity of the extract on PGHS-2.

INFLUENCE OF CYCLOOXYGENASE INHIBITORS ON GUT IMMUNE CELL DISTRIBUTION AND APOPTOSIS RATE IN EXPERIMENTAL SEPSIS

The aim of this study was to determine if cyclooxygenase (COX) inhibitors influence immune cell distribution in the small intestinal mucosa and mesenteric lymph nodes (MLNs), the grade of mucosal damage, and the rate of apoptosis in septic rats. The effects induced by a selective COX-2 inhibitor (SC-236) were compared with those of a nonselective COX-1 and -2 inhibitor (indomethacin). Cecal ligation and puncture (CLP), CLP + SC-236 p.o, and CLP + indomethacin p.o, were evaluated. Animals were harvested 6 and 24 h after CLP, respectively. The concentration of proinflammatory cytokines was higher in ascitic fluid than in blood. CLP + SC-236 attenuated IL-6 in plasma and in ascitic fluid and CLP + indomethacin augmented TNF-alpha in ascitic fluid compared with CLP at 6 h. CLP + SC-236 gave a lesser degree of mucosal damage compared with CLP alone or with indomethacin at 6 and 24 h (P < 0.05). Untreated CLP had significant reductions in the number of T lymphocytes in the villi and increases of macrophages in the mucosa and MLNs compared with controls (P < 0.05). CLP + indomethacin decreased T lymphocytes in the villi and MLNs. CLP caused an enhanced apoptosis in the mucosa compared with controls (P < 0.05), pretreatment with COX inhibitors did not significantly change this. Both COX inhibitors enhanced apoptosis in MLNs and attenuated the increase of macrophages in mucosa and MLNs (P < 0.05). It is proposed that the increased apoptosis and the decrease in T cells in the mucosa may be causally related. Apoptosis of lymphocytes may impair the immunologic defense in sepsis. Furthermore, loss of intestinal epithelial cells may compromise bowel wall integrity and facilitate translocation.

Lipid signaling in experimental epilepsy

Glutamate release activates signaling pathways important for learning and memory, and over-stimulation of these pathways during seizures leads to aberrant synaptic plasticity associated with hyper-excitable, seizure-prone states. Seizures induce rapid accumulation of membrane lipid-derived fatty acids at the synapses which, evidence suggests, regulate maladaptive connectivity. Here we give an overview of the significance of the arachidonyl- and inositol-derived messengers, prostaglandins (PGs) and diacylglycerol (DAG), in experimental models of epilepsy. We use studies conducted in our own laboratory to highlight the pro-epileptogenic role of cyclooxygenase-2 (COX-2) and its products, the PGs, and we discuss the possible mechanisms by which PGs may regulate membrane excitability and synaptic transmission at the cellular level. We conclude with a discussion of AA-DAG signaling in synaptic plasticity and seizure susceptibility with an emphasis on recent studies in our laboratory involving DAG kinase epsilon (DGKepsilon)-knockout mice.

Comparative study of anti-inflammatory and ulcerogenic activities of different cyclo-oxygenase inhibitors

The aim of the present work was to study the in vivo anti-inflammatory activity of six NSAIDs, ibuprofen, diclofenac, nimesulide, meloxicam, celecoxib and rofecoxib, using the rat air-pouch model of inflammation to characterize the ability of these drugs to induce gastric damage and PGE(2) inhibition. Selective compounds were observed to have no ulcerogenic properties at anti-inflammatory doses; however, these drugs were weaker inhibitors of several inflammatory aspects such as cell influx and exudate formation. In contrast, the non-selective and preferential compounds present anti-inflammatory properties at lower doses than presented by selective drugs. At anti-inflammatory doses, only meloxicam and ibuprofen produced gastric damage and inhibition of PGE(2) synthesis, suggesting that ulcerogenic properties of NSAIDs cannot be predicted by their selectivity index, since meloxicam demonstrates ulcerogenic properties despite its preferential profile.

Radiosynthesis and in vivo evaluation of 11C-labeled 1,5-diarylpyrazole derivatives for mapping cyclooxygenases

We prepared 11C-labeled 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole ([11C]1) and 4-[5-(4-methoxyphenyl)-3-trifluoromethyl-1H-pyrazol-1-yl]benzenesulfonamide ([11C]2) for imaging COX-1 and COX-2 isoforms, respectively, by positron emission tomography. [11C]1 and [11C]2 were synthesized in high radiochemical yields by O-[11C]methylation with [11C]methyl triflate in acetone containing an equivalent of NaOH as a base with respect to the phenolic precursors. In vivo evaluation in rats bearing AH109A hepatoma demonstrated minimal specific binding of [11C] to COX-1 in peripheral organs, such as the spleen and small intestine. Carrier-saturable uptake of [11C]2 was found in the spleen, but COX-2-specific binding of [11C]2 was not identifiable in the brain, AH109A hepatoma or other peripheral organs, although ex vivo autoradiography showed regionally different distribution in the brain and AH109A. The results suggest that neither [11C]1 nor [11C]2 is a suitable radioligand for in vivo biomarkers of COX enzymes, mainly because of marked non-specific binding.

Inhibitory effect of the coffee diterpene kahweol on carrageenan-induced inflammation in rats

Previous studies reported that kahweol, a coffee-specific diterpene, inhibits cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression in cultured lipopolysaccharide-activated macrophages. The aim of this study was to confirm the anti-inflammatory effects of kahweol by examining its effect on the inflammatory response induced by carrageenan in a rat using an acute air pouch inflammation model. Kahweol significantly reduced the levels of the inflammatory process markers in the air pouch, such as the volume of exudates, the amount of protein and the number of leukocytes and neutrophils. The levels of nitrite, TNF-alpha and prostaglandin E2 (PGE2) were also markedly lower in the air pouch of the kahweol-treated animals than in the controls. Immunoblot analysis showed that kahweol reduced the COX-2 and iNOS expression level in the exudate cells. The histological examination showed that there was a lower inflammatory response in the pouch tissues from the kahweol-treated animals. In addition, kahweol significantly reduced the paw edema induced by carrageenan and also markedly reduced the level of PGE2 production in the inflamed paw. These results suggest that kahweol has significant anti-inflammatory effects in vivo, which might be due to the inhibition of iNOS and COX-2 expression in the inflammatory sites.

Effects of meloxicam on renal function in dogs with hypotension during anaesthesia

OBJECTIVE

To evaluate the effects of meloxicam on renal function in dogs anaesthetized and rendered hypotensive with acepromazine-thiopental-isoflurane.

ANIMALS

Eight healthy beagles, four males and four females, 25.6 +/- 19.3 months old and weighing 12.8 +/- 2.0 kg.

MATERIALS AND METHODS

Either meloxicam suspension at a dose of 0.133 mL kg(-1) (0.2 mg kg(-1)) or 0.133 mL kg(-1) saline solution (control), were given by mouth (PO) in a randomized, cross-over fashion. The treatment or control was given 3 hours before anaesthesia. Dogs were sedated with intramuscular acepromazine 0.1 mg kg(-1). Anaesthesia was induced with intravenous thiopental, followed by tracheal intubation and maintenance with isoflurane in oxygen and air, delivered using a semi-closed breathing system. Renal function was quantified using serum biochemistry, urinalysis and glomerular filtration rate measured by scintigraphy. Analysis of variance or Friedman anova were used for statistical analysis.

RESULTS

Values (mean +/- SD) for mean arterial blood pressure did not differ significantly between treatments but was low (54 +/- 7 mmHg) during anaesthesia. Glomerular filtration rate did not differ significantly between treatments or over time, and results of urine and serum analysis were within reference ranges after meloxicam treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Meloxicam caused no adverse effects on renal function when given to healthy dogs anaesthetized and rendered hypotensive with acepromazine, thiopental and isoflurane.

Anti-inflammatory Activity of Ailanthus altissima in Ovalbumin-Induced Lung Inflammation

As part of an ongoing investigation to find bioactive medicinal herbs exerting anti-inflammation activity, the effect of an ethanol extract from the parts of Ailanthus altissima (Simaroubaceae) was evaluated in both in vitro and in in vivo system. The ethanol extract of A. altissima (EAa) inhibited generation of the cyclooxygenase-2 (COX-2) dependent phases of prostaglandin D2 in bone marrow-derived mast cells (BMMC) in a concentration-dependent manner with an IC50 value of 214.6 microg/ml. However, this compound did not inhibit COX-2 protein expression up to a concentration of 400 microg/ml in the BMMC, indicating that EAa directly inhibits COX-2 activity. In addition, EAa inhibited leukotriene C4 production with an IC50 value of 25.7 microg/ml. Furthermore, this compound inhibited degranulation reaction in a dose dependent manner, with an IC50 value of 27.3 microg/ml. Ovalbumin (OVA)-sensitized mice were orally pretreated with EAa before aerosol challenges. EAa reduced the eosinophil infiltration into the airway and the eotaxin, IL-4, and IL-13 mRNA expression levels. These results suggest that the anti-inflammation activity of A. altissima in OVA-induced lung inflammation may occur in part via the down regulation of T(H)2 cytokines and eotaxin transcripts as well as the inhibition of inflammatory mediators.

Effects of blue honeysuckle (Lonicera caerulea L.) extract on lipopolysaccharide-induced inflammation in vitro and in vivo

The aim of the present study was to investigate the effects of blue honeysuckle extract (BHE), which contains high level of phenolic compounds, on endotoxin-induced uveitis (EIU). Male Lewis rats were randomly divided into 5 groups with 14 rats in each (eight rats for collection of aqueous humor, six rats for histologic examination). EIU was induced by a footpad injection of lipopolysaccharide (LPS). 1, 10, or 100 mg of BHE was injected intravenously immediately after LPS injection. The aqueous humor was collected at 24 h after LPS injection, the number of infiltrating cells, protein concentration, nitric oxide (NO), tumor necrosis factor (TNF)-alpha, and prostaglandin (PG)-E2 levels in the aqueous humor were determined. Some eyes were enucleated for histologic examination and immunohistochemical analysis. Immunohistochemical staining with a monoclonal antibody against activated nuclear factor (NF)-kappaB was performed to evaluate the effect of BHE on NF-kappaB activation. To further clarify the anti-inflammatory effect, RAW264.7 cells (a mouse macrophage cell line) were stimulated with LPS in the presence or absence of BHE and its major phenolics, cyanidin 3-glucoside (C3G), cyanidin 3-rutinoside (C3R), chlorogenic acid (CA). Expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) were analyzed by Western blot method. BHE treatment significantly reduced the inflammatory cell infiltration, the protein concentration, the levels of NO, TNF-alpha and PGE2 in the aqueous humor and improved histologic status of the ocular tissue. The number of activated NF-kappaB-positive cells was lower in the iris-ciliary body treated with BHE at 3 h after LPS injection. BHE significantly suppressed the production of NO, PGE2 and TNF-alpha in the culture medium as well as the expression of iNOS and COX-2 by LPS-stimulated RAW264.7 cells in a dose-dependent fashion. C3G, C3R and CA showed no or weak inhibitory effects on the level of inflammatory mediators and the expression of iNOS and COX-2. These results suggest that BHE attenuates the degree of inflammation in eyes with EIU by inhibiting the NF-kappaB dependent signaling pathway and the subsequent production of proinflammatory mediators.

1α,25-Dihydroxyvitamin D3 treatment does not alter neuronal cyclooxygenase-2 expression in the cerebral cortex after stroke

The inducible prostaglandin synthase, cyclooxygenase-2, is upregulated in response to cerebral ischemia and contributes to potentiation of oxidative injury. Cyclooxygenase-2 expression is regulated by retinoic acid receptors, which form heterodimers with vitamin D receptors and vitamin D. In addition, vitamin D has been reported to have neuroprotective qualities. The aim of this study was to examine whether the biologically active vitamin D3-metabolite 1alpha,25-dihydroxyvitamin D3 (1,25-D3), influences the expression of inducible cyclooxygenase-2 in photothrombotically lesioned brain or is part of an independent neuroprotective mechanism. We compared groups of nonlesioned control rats and infarcted animals, which were treated with either 1,25-D3 or solvent at different times postlesion. In control animals, cyclooxygenase-2 immunoreactivity was readily evident in almost all cortical neurons of layers II/III as well as in a few pyramidal cells in layer V. Following photothrombotic infarction of the right cortical hindlimb area, there was a significant, but transient, increase in cyclooxygenase-2 labeling which was restricted to neurons of the injured hemisphere in both 1,25- D3-treated and solvent-treated rats. Highest levels of cyclooxygenase-2 immunoreactivity were seen at 12 and 24 h postlesion, followed by a gradual decrease at later time points. However, no significant differences were detected between 1,25-D3-treated and solvent-treated lesioned rats, indicating that postischemic neuronal cyclooxygenase-2 upregulation is not influenced by 1,25-D3. It is concluded that the neuroprotective effect of 1,25-D3 does not depend on modulations of neuronal COX-2 expression caused by postlesional hyperexcitation.

Inhibition of 12- and 15-lipoxygenase activities and protection of human and tilapia low density lipoprotein oxidation by I-Tiao-Gung (Glycine tomentella)

I-Tiao-Gung, Glycine tomentella, has been used extensively as a traditional herbal medicine to relieve physical pain, but its bioactivity has not been studied systematically. Ninety-five percent ethanol extracts of G. tomentella (GT-E) showed antioxidant activity in human plasma by prolonging the lag phase (+Tlag) of Cu2+-induced LDL oxidation and were dose dependent. The +Tlag of LDL combined with 3.2 microg/mL GT-E was similar to that with 2.0 microM (ca. 0.5 microg/mL) Trolox. A similar inhibitory effect was found toward tilapia plasma LDL. In addition, GT-E inhibited tilapia thrombocyte (nucleated platelet) 5-, 12-, and 15-lipoxygenase (LOX). The IC50 values were 0.43, 0.72, and 0.42 microg/mL, respectively, whereas the IC50 values for nordihydroguaiaretic acid (NDGA) on 5-, 12-, and 15-LOX were 2.3, 1.6, and 1.7 microg/mL, respectively. The IC50 value for cyclooxygenase-2 (COX-2) inhibition by GT-E was 42.0 microg/mL, whereas the IC50 value by indomethacin as a positive control was 0.61 microLg/mL. The prevention of LDL oxidation and the dual inhibition of LOX and COX-2 are indicative of the possible roles of I-Tiao-Gung in antiatherosclerosis and anti-inflammation.

A comparison between the effects of acetaminophen and celecoxib on bone fracture healing in rats

OBJECTIVES

This study compared the acute treatment effects of systemic analgesics with (celecoxib) and without anti-inflammatory activity (acetaminophen) on bone fracture healing.

STUDY DESIGN

Longitudinal time study of fracture healing in rats.

METHODS

Closed, mid diaphyseal femur fractures were produced in female Sprague-Dawley rats. The rats were treated for 10 days after fracture with 60 or 300 mg/kg of acetaminophen, 3 or 6 mg/kg of celecoxib, or vehicle by once-daily oral dosing. Fracture healing was measured after 8 weeks by radiographic examination, mechanical testing, and histology.

RESULTS

Radiographic scoring indicated that acute celecoxib treatment significantly impaired fracture healing; acetaminophen treatment had no negative effect. Mechanical testing supported the radiographic observations. No negative effects of celecoxib or acetaminophen treatment on the structural properties (peak torque and torsional rigidity) of the healing femurs were detected. In contrast, celecoxib treatment, but not acetaminophen treatment, significantly reduced the material properties (maximum shear stress and shear modulus) of the healing femurs (P < 0.001). Post-mechanical testing examination of the healing femurs found that 73% of the vehicle-treated or acetaminophen-treated femurs had healed as unions (30/41), 27% failed as incomplete unions (11/41), and none failed as nonunions (0%). In contrast, only 21% of the fractured femurs from the celecoxib treated rats had healed as unions (7/34), 53% failed as incomplete unions (18/34), and 26% failed as nonunions (9/34). The proportion of nonunions among the celecoxib-treated rats was significantly higher compared with the control and acetaminophen-treated rats (P < 0.001). Histologic examination indicated that similar to previous studies, celecoxib treatment, but not acetaminophen treatment, altered normal fracture callus morphology in which cartilage rather than new bone abuts the fracture site.

CONCLUSIONS

No negative effect from acute acetaminophen treatment on fracture healing was detected. In contrast, acute treatment with celecoxib, a selective cyclooxygenase-2 inhibitor with anti-inflammatory activity, significantly impaired fracture healing.

Cyclooxygenase-2 enzyme inhibitory triterpenoids from Picrorhiza kurroa seeds

A bioassay guided phytochemical study of the ethyl acetate extract of the seeds of Picrorhiza kurroa afforded a new triterpenoid, 2alpha, 3beta, 19beta, 23-tetrahydroxyolean-12-en-28-O-beta-D-glucoside (1), along with five known triterpenoids, 2alpha, 3beta, 19beta, 23-tetrahydroxyolean-12-en-28-oic acid (2), 2alpha, 3beta, 23-trihydroxyolean-12-en-28-O-beta-d-glucoside (3), 2alpha, 3beta, 23-trihydroxyolean-12-en-28-oic acid (4), 2alpha, 3beta, 19beta, trihydroxyolean-12-en-28-oic acid (5), and 2alpha, 3beta, 6beta, 23-tetrahydroxyolean-12-en-28-oic acid (6). Their structures were established by extensive NMR spectral studies. The acetyl derivatives, compounds 7 and 8, were prepared from compounds 1 and 2, respectively, to aid in their structure elucidation. The inhibition of cyclooxygenase-2 (COX-2) enzyme by compounds 1--6 at 100 microg/mL was 38.3%, 39%, 37%, 49.6%, 25%, and 45.0%, respectively. However, compounds 1--6, at 100 microg/mL, did not inhibit cyclooxygenase-1 (COX-1) enzyme. Compound 1 is a novel triterpenoid and compounds 1--6 are isolated for the first time from the seeds of P. kurroa.

A Real Time Quantitative PCR Analysis and Correlation of COX-1 and COX-2 Enzymes in Inflamed Dental Pulps Following Administration of Three Different NSAIDs

Dental pain is encountered daily by clinicians. Nonsteroidal anti-inflammatory drugs (NSAIDs) commonly used for pain management are traditionally cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) inhibitors, and more recently selective COX-2 inhibitors. This study was designed to identify and quantify COX-1 and COX-2 gene expression level in inflamed rat molar pulps after administration of three NSAIDs: Celebrex, Vioxx, and Advil. Fifty male Wistar rats had their first and second molar pulps exposed and sealed with Cavit for 4 days. Rats were randomly divided into the three drug groups and two control groups. RNA was isolated from the rat pulps. Real Time Quantitative Reverse Transcriptase-Polymerase Chain Reaction assay, a relatively new PCR technique, was used to quantify COX-1 and COX-2 mRNA. Statistical analysis demonstrated no significant differences in COX-1 and COX-2 levels among the drug groups. However, Vioxx and Advil significantly reduced COX-2 expression levels compared to inflamed (positive control) pulps (p < 0.05).

The post-operative analgesic efficacy and tolerability of lumiracoxib compared with placebo and naproxen after total knee or hip arthroplasty

BACKGROUND

Lumiracoxib is a novel selective cyclooxygenase-2 (COX-2) inhibitor in development for the treatment of chronic and acute pain.

METHODS

This randomized, double-blind multicentre study enrolled 180 patients (aged 18-80 years) with moderate-to-severe pain (>or=2 on a 4-point categorical scale) within 48 h of unilateral total knee or total hip arthroplasty. Patients were randomized to receive lumiracoxib 400 mg once daily (n = 60), placebo (n = 60) or naproxen 500 mg twice daily (n = 60). The study consisted of a 12-h single-dose phase followed by a multiple-dose phase (up to 96 h or until discontinuation). The primary efficacy measure was the summed (time-weighted) pain intensity difference over 0-8 h after the first dose (SPID-8).

RESULTS

Lumiracoxib and naproxen were comparable and both treatments were superior to placebo for the primary efficacy measure, SPID-8. Both treatments were generally similar and also superior to placebo for the secondary efficacy measures during both the single- and multiple-dose phases for up to 96 h. Both active treatments were well tolerated.

CONCLUSION

Lumiracoxib is an effective alternative to traditional non-selective non-steroidal anti-inflammatory drugs (NSAIDs) for the treatment of post-operative pain.

Spontaneous effects of low-level laser therapy (650 nm) in acute inflammatory mouse pleurisy induced by carrageenan

OBJECTIVE

Our aim was to investigate the effect of low-level laser therapy (LLLT), 650-nm wavelength, on acute inflammatory pleurisy.

BACKGROUND DATA

There is only scattered evidence of anti-inflammatory effects from LLLT and dosage characteristics, and the effect on pleurisy inflammation has yet to be investigated.

METHODS

A classical experimental model of pleurisy was used in a sample of 40 Balb male mice, randomly divided into five groups. Inflammation was induced by carrageenan (0.5 mg/cavity) administered by intrathoracic injections. Four groups received the inflammatory agent, and one received injections of sterile saline solution. At 1, 2, and 3 h after injections, LLLT irradiation was performed, with the same power (2.5 mW), but different irradiation times. The energy densities at each of the three treatment sessions were 0 J/cm(2) (placebo), 3 J/cm(2), 7.5 J/cm(2), and 15 J/cm(2), respectively.

RESULTS

Total and differential cell analysis at 4 h after induction of pleurisy showed a significant reduction of inflammatory cell migration for all groups treated with active laser. However, at 4 h after injection, the most significant (p < 0.001) reduction of leukocyte cell migration was seen in the 7.5 J/cm(2) group, at 2.7 (95% CI: 2.5-2.9) x 10(6), versus 7.9 (95% CI: 6.7-9.1) x 10(6) in the placebo control group. The greatest reduction of inflammatory cells was registered for neutrophils.

CONCLUSIONS

LLLT administered at 1-3 h after the induction of inflammatory pleurisy significantly reduces the inflammatory cell migration measured. Under these conditions and at 2.5 mW, 7.5 J/cm(2) was more effective than 3 J/cm(2) and 15 J/cm(2).

Effects of Morus alba leaf extract on the production of nitric oxide, prostaglandin E2 and cytokines in RAW264.7 macrophages

Morus alba leaf methanolic extract and its fractions (chloroform, butanol, and aqueous fractions) were found to inhibit NO production in LPS-activated RAW264.7 macrophages without an appreciable cytotoxic effect at concentration from 4 to 100 microg/ml. LPS-induced PGE2 production was significantly reduced only by butanol fraction. In addition, M. alba leaf extract and its fractions significantly decreased the production of TNF-alpha. These findings suggest that M. alba leaf extract seems to be able in suppressing inflammatory mediators. Moreover, the inhibitory activities on COX-2 and iNOS of its butanol fraction are warranted for further elucidation of active principles for development of new antiinflammatory agents.

Discovery and Biological Evaluation of the Novel Naturally Occurring Diterpene Pepluanone as Antiinflammatory Agent

From the whole plant of Euphorbia peplus L., a new diterpene based on a rare pepluane skeleton, named pepluanone (1), was isolated together with a known pepluane diterpene (2). The stereostructure of pepluanone was determined on the basis of an extensive NMR study, MS data, and chemical reaction. The ability of these compounds to act as antiinflammatory agents has been evaluated for the first time by in vivo tests on carrageenin-induced rat paw edema, an experimental model of acute inflammation. Comparison of the bioactivity of pepluanone and compound 2 in terms of chemical structure, evidenced the high efficiency of pepluanone and the absence of appreciable activity for compound 2, thus giving a first insight into the structure-activity relationship. Further in vitro experiments performed on pepluanone let us hypothesize that its activity could be explained in reducing the production of nitric oxide, prostaglandin E(2), and TNF-alpha by inhibiting the expression of inducible nitric oxide synthase, cyclooxygenase-2, and TNF-alpha mRNA through the down-regulation of NF-kappaB binding activity.