Cyclooxygenase-2 and its regulation in inflammation

"Azole" as privileged heterocycle for targeting the inducible cyclooxygenase enzyme

An over-expression of COX-2 isoenzyme belonging to the Cyclooxygenase Enzyme Family triggers the overproduction of pro-inflammatory prostaglandins that instigate the development of chronic inflammation and related disorders. Hence, the rationally designed drugs for mitigating over-activity of COX-2 isoenzyme play a regulatory role toward the alleviation of the progression of these disorders. However, a selective COX-2 inhibition chemotherapy prompts several side effects that necessitate the identification of novel molecular scaffolds for deliberating state-of-the-art drug designing strategies. The heterocyclic "azole" scaffold, being polar and hydrophilic, possesses remarkable physicochemical advantages for designing physiologically active molecules capable of interacting with a wide range of biological components, including enzymes, peptides, and metabolites. The substituted derivatives of azole nuclei enable a comprehensive SAR analysis for the appraisal of bioactive profile of the deliberated molecules for obtaining the rationally designed compounds with prominent activities. The comprehensive SAR analysis readily prompted the identification of Y-shaped molecules and the eminence of bulkier group for COX-2 selective inhibition. This review presents an epigrammatic collation of the pharmacophore-profile of the chemotherapeutics based on azole motif for a selective targeting of the COX-2 isoenzyme.

An In Vitro Evaluation of the Molecular Mechanisms of Action of Medical Plants from the Lamiaceae Family as Effective Sources of Active Compounds against Human Cancer Cell Lines

It is predicted that 1.8 million new cancer cases will be diagnosed worldwide in 2020; of these, the incidence of lung, colon, breast, and prostate cancers will be 22%, 9%, 7%, and 5%, respectively according to the National Cancer Institute. As the global medical cost of cancer in 2020 will exceed about $150 billion, new approaches and novel alternative chemoprevention molecules are needed. Research indicates that the plants of the Lamiaceae family may offer such potential. The present study reviews selected species from the Lamiaceae and their active compounds that may have the potential to inhibit the growth of lung, breast, prostate, and colon cancer cells; it examines the effects of whole extracts, individual compounds, and essential oils, and it discusses their underlying molecular mechanisms of action. The studied members of the Lamiaceae are sources of crucial phytochemicals that may be important modulators of cancer-related molecular targets and can be used as effective factors to support anti-tumor treatment.

Role of Oxygen Supply in Macrophages in a Model of Simulated Orthodontic Tooth Movement

Apart from periodontal ligament fibroblasts, immune cells like macrophages also play an important mediating role in orthodontic tooth movement (OTM). Upon orthodontic force application to malpositioned teeth, macrophages in the periodontal ligament get exposed to both mechanical strain and hypoxic conditions (via a compression of blood vessels). In this study, we assessed the relative impact of orthodontically induced mechanical strain and hypoxic conditions on macrophages for the mediation and regulation of OTM. Macrophages were stimulated with physiological orthodontic compressive forces of 2 g/cm² for 4 h and 24 h on gas-impermeable or gas-permeable cell culture plates under normoxic or hypoxic cell culture conditions. We quantified expression of genes involved in inflammation (Tnf, Il-6, and Cox-2), extracellular remodelling (Mmp-9), and angiogenesis (Vegf) by RT-qPCR. Furthermore, we analysed HIF-1α, prostaglandin-E2, and VEGF protein expression via immunoblotting or ELISA. Mechanical strain and oxygen supply both differentially affected expression of genes and proteins involved in inflammation and angiogenesis. In this context, we found that HIF-1α protein levels were elevated by combined mechanical strain and hypoxic conditions, whereas gas-permeable plates providing sufficient oxygen supply prevented HIF-1α stabilization at the protein level after pressure application on macrophages. Our results thus indicate that macrophages involved in the mediation of OTM are affected by and respond differently to hypoxic conditions and mechanical compressive strain, which occur concomitantly during OTM, than periodontal ligament fibroblasts (PDLF), thus indicating different roles of these cells in the regulation of OTM at the cellular-molecular level. We further observed that contrary to PDLF HIF-1α stabilization in macrophages is rather induced via the decreased oxygen supply associated with OTM than via mechanotransduction by mechanical strain.

Combined administration of docosahexaenoic acid and thyroid hormone synergistically enhances rat liver levels of resolvins RvD1 and RvD2

Supplementation with omega-3 fatty acids or thyroid hormone (T₃) exhibit negative effects on inflammatory reactions in experimental animals. The aim of this work was to assess the hypothesis that docosahexaenoic acid (DHA) plus T₃ co-administration enhances liver resolvin (Rv) levels as inflammation resolution mediators. Combined DHA (daily doses of 300 mg/kg for 3 consecutive days)-T₃ (0.05 mg/kg at the fourth day) administration significantly increased the content of hepatic RvD1 and RvD2, without changes in that of RvE1 and RvE2, an effect that exhibits synergy when compared to the separate DHA and T₃ treatments. Under these conditions, liver DHA levels increased by DHA administration were diminished when combined with T₃ (p < 0.05), suggesting enhancement in resolvin D biosynthesis in extrahepatic tissues. It is concluded that co-administration of DHA and T₃ rises the capacity of the liver for inflammation resolution by augmenting RvD1(2) availability, which represents an important protocol in hepatoprotection in the clinical setting.

Effect of oral administration of robenacoxib on inhibition of paracentesis-induced blood-aqueous barrier breakdown in healthy cats

OBJECTIVE To determine the effect of oral administration of robenacoxib on inhibition of anterior chamber paracentesis (ACP)-induced breakdown of the blood-aqueous barrier (BAB) and assess whether robenacoxib can cross an intact BAB in healthy cats. ANIMALS 12 healthy adult domestic shorthair cats. PROCEDURES Cats received robenacoxib (6-mg tablet in a treat, PO; n = 6) or a control treatment (treat without any drug, PO; 6) once daily for 3 days, beginning 1 day before ACP. One eye of each cat served as an untreated control, whereas the other underwent ACP, during which a 30-gauge needle was used to aspirate 100 μL of aqueous humor for determination of robenacoxib concentration. Both eyes of each cat underwent anterior chamber fluorophotometry at 0 (immediately before), 6, 24, and 48 hours after ACP. Fluorescein concentration and percentage fluorescein increase were used to assess extent of ACP-induced BAB breakdown and compared between cats that did and did not receive robenacoxib. RESULTS Extent of BAB breakdown induced by ACP did not differ significantly between cats that did and did not receive robenacoxib. Low concentrations of robenacoxib were detected in the aqueous humor (mean, 5.32 ng/mL; range, 0.9 to 16 ng/mL) for 5 of the 6 cats that received the drug. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that oral administration of robenacoxib did not significantly decrease extent of BAB breakdown in healthy cats. Detection of low robenacoxib concentrations in the aqueous humor for most treated cats indicated that the drug can cross an intact BAB.

Mechanistic insights into the anticancer mode of action of an herbal drug

Medicinal plants are a vast repository of natural compounds with therapeutic effects against various ailments. Bioactive compounds of these plants have shown to possess anticancer activities. Cancer is one of the fatal diseases causing premature deaths across the world. Two important metabolites, serpentine, a major secondary metabolite of Rauwolfia serpentina, and amarogentin, isolated from Swertia chirata, are found to possess anticancer properties. A comparable in silico analysis of the two anticancer agents serpentine and amarogentin has been done to evaluate their ability to inhibit two potential molecular targets for cancer, nuclear factor-κB (NF-κB) and cyclo-oxygenase-2 (COX-2). The least binding energies of amarogentin with NF-κB and COX-2 are −7·173 and −7·649, respectively, which are better than that of serpentine. The molecular simulation of amarogentin and serpentine suggests that amarogentin has better binding affinities with both cancer targets. Amarogentin is thermodynamically more stable with COX-2 than with NF-κB. Amarogentin is a potent anticancer agent as evidenced by the inhibition of COX-2. This finding would be beneficial to people with cancer.

Nonsteroidal Anti-inflammatory Drug Use in Horses

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective anti-inflammatory and analgesic agents and are arguably the most commonly used class of drugs in equine medicine. This article provides a brief review of the mechanism of action, therapeutic uses, pharmacokinetics, and adverse effects associated with their use in horses. The use of COX-2 selective NSAIDs in veterinary medicine has increased over the past several years and special emphasis is given to the use of these drugs in horses. A brief discussion of the use of NSAIDs in performance horses is also included.

Targeting arachidonic acid pathway by natural products for cancer prevention and therapy

Arachidonic acid (AA) pathway, a metabolic process, plays a key role in carcinogenesis. Hence, AA pathway metabolic enzymes phospholipase A₂s (PLA₂s), cyclooxygenases (COXs) and lipoxygenases (LOXs) and their metabolic products, such as prostaglandins and leukotrienes, have been considered novel preventive and therapeutic targets in cancer. Bioactive natural products are a good source for development of novel cancer preventive and therapeutic drugs, which have been widely used in clinical practice due to their safety profiles. AA pathway inhibitory natural products have been developed as chemopreventive and therapeutic agents against several cancers. Curcumin, resveratrol, apigenin, anthocyans, berberine, ellagic acid, eugenol, fisetin, ursolic acid, [6]-gingerol, guggulsteone, lycopene and genistein are well known cancer chemopreventive agents which act by targeting multiple pathways, including COX-2. Nordihydroguaiaretic acid and baicalein can be chemopreventive molecules against various cancers by inhibiting LOXs. Several PLA₂s inhibitory natural products have been identified with chemopreventive and therapeutic potentials against various cancers. In this review, we critically discuss the possible utility of natural products as preventive and therapeutic agents against various oncologic diseases, including prostate, pancreatic, lung, skin, gastric, oral, blood, head and neck, colorectal, liver, cervical and breast cancers, by targeting AA pathway. Further, the current status of clinical studies evaluating AA pathway inhibitory natural products in cancer is reviewed. In addition, various emerging issues, including bioavailability, toxicity and explorability of combination therapy, for the development of AA pathway inhibitory natural products as chemopreventive and therapeutic agents against human malignancy are also discussed.

Valdecoxib for the management of chronic and acute pain

Cyclooxygenase-2 specific inhibitors have anti-inflammatory and analgesic properties, and are effective in managing a wide range of chronic and acute painful conditions such as adult rheumatoid arthritis, osteoarthritis, migraine, primary dysmenorrhea and postoperative pain. Valdecoxib, an orally administered cyclooxygenase-2 specific inhibitor, provides effective pain relief for both chronic and acute conditions, and reduces postoperative opioid use, with a concomitant reduction in opioid-related adverse events. Valdecoxib also has superior gastrointestinal safety compared with nonspecific nonsteroidal anti-inflammatory drugs, and at therapeutic doses, it is generally safe and well tolerated in terms of renal and cardiovascular events. This drug profile reviews the efficacy, safety and tolerability of valdecoxib for the management of chronic and acute pain.

Effects of intrauterine infection or inflammation on fetal lung development

1. Intrauterine infection or inflammation is common in cases of preterm birth. Preterm infants are at risk of acute respiratory distress as a result of lung immaturity; evidence of exposure to infection and/or inflammation before birth is associated with a reduced risk of neonatal respiratory distress syndrome (RDS). Experimentally induced intrauterine inflammation or infection in sheep causes a precocious increase in pulmonary surfactant in the preterm lungs that improves preterm lung function, consistent with the reduced risk of RDS in human infants exposed to infection and/or inflammation before birth. 2. The effects of intrauterine inflammation on fetal lung development appear to result from direct action of proinflammatory stimuli within the lungs rather than by systemic signals, such as the classical glucocorticoid-mediated lung maturation pathway. However, paracrine and/or autocrine production and/or metabolism of glucocorticoids in fetal lung tissue may occur as a result of inflammation-induced changes in the expression of 11β-hydroxysteroid dehydrogenase (types 1 and 2). 3. Likely candidates that mediate inflammation-induced surfactant production by the preterm lung include prostaglandin E₂ and/or other arachidonic acid metabolites. Intrauterine inflammation induces the expression of enzymes responsible for prostaglandin production in fetal lung tissue. Inhibition of prostaglandin production prevents, at least in part, the effects of inflammation on fetal lungs. 4. Our experiments are identifying mechanisms of surfactant production by the preterm lungs that may be exploited as novel therapies for preventing respiratory distress in preterm infants. Elucidation of the effects of inflammation on the fetal lungs and other organs will allow more refined approaches to the care of preterm infants exposed to inflammation in utero.

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.

Peroxisome Proliferator Activated Receptor-α Agonist Slows the Progression of Hypertension, Attenuates Plasma Interleukin-6 Levels and Renal Inflammatory Markers in Angiotensin II Infused Mice

The anti-inflammatory properties of PPAR-α plays an important role in attenuating hypertension. The current study determines the anti-hypertensive and anti-inflammatory role of PPAR-α agonist during a slow-pressor dose of Ang II (400 ng/kg/min). Ten to twelve week old male PPAR-α KO mice and their WT controls were implanted with telemetry devices and infused with Ang II for 12 days. On day 12 of Ang II infusion, MAP was elevated in PPAR-α KO mice compared to WT (161 ± 4 mmHg versus 145 ± 4 mmHg) and fenofibrate (145 mg/kg/day) reduced MAP in WT + Ang II mice (134 ± 7 mmHg). Plasma IL-6 levels were higher in PPAR-α KO mice on day 12 of Ang II infusion (30 ± 4 versus 8 ± 2 pg/mL) and fenofibrate reduced plasma IL-6 in Ang II-treated WT mice (10 ± 3 pg/mL). Fenofibrate increased renal expression of CYP4A, restored renal CYP2J expression, reduced the elevation in renal ICAM-1, MCP-1 and COX-2 in WT + Ang II mice. Our results demonstrate that activation of PPAR-α attenuates Ang II-induced hypertension through up-regulation of CYP4A and CYP2J and an attenuation of inflammatory markers such as plasma IL-6, renal MCP-1, renal expression of ICAM-1 and COX-2.

Bauer ketones 23 and 24 from Echinacea paradoxa var. paradoxa inhibit lipopolysaccharide-induced nitric oxide, prostaglandin E2 and cytokines in RAW264.7 mouse macrophages

Among the nine Echinacea species, E. purpurea, E. angustifolia and E. pallida, have been widely used to treat the common cold, flu and other infections. In this study, ethanol extracts of these three Echinacea species and E. paradoxa, including its typical variety, E. paradoxa var. paradoxa, were screened in lipopolysaccharide (LPS)-stimulated macrophage cells to assess potential anti-inflammatory activity. E. paradoxa var. paradoxa, rich in polyenes/polyacetylenes, was an especially efficient inhibitor of LPS-induced production of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) by 46%, 32%, 53% and 26%, respectively, when tested at 20 μg/ml in comparison to DMSO control. By bioactivity-guided fractionation, pentadeca-8Z-ene-11, 13-diyn-2-one (Bauer ketone 23) and pentadeca-8Z, 13Z-dien-11-yn-2-one (Bauer ketone 24) from E. paradoxa var. paradoxa were found primarily responsible for inhibitory effects on NO and PGE2 production. Moreover, Bauer ketone 24 was the major contributor to inhibition of inflammatory cytokine production in LPS-induced mouse macrophage cells. These results provide a rationale for exploring the medicinal effects of the Bauer ketone-rich taxon, E. paradoxa var. paradoxa, and confirm the anti-inflammatory properties of Bauer ketones 23 and 24.

Renal protective effect of chronic inhibition of COX-2 with SC-58236 in streptozotocin-diabetic rats

The induction of renal cyclooxygenase-2 (COX-2) in diabetes has been implicated in the renal functional and structural changes in models where hypertension or uninephrectomy was superimposed. We examined the protective effects of 3 mo treatment of streptozotocin-diabetic rats with a highly selective COX-2 inhibitor (SC-58236) in terms of albuminuria, renal hypertrophy, and the excretion of TNF-α and TGF-β, which have also been implicated in the detrimental renal effects of diabetes. SC-58236 treatment (3 mg·kg(-1)·day(-1)) of diabetic rats resulted in reduced urinary excretion of PGE(2), 6-ketoPGF(1α), and thromboxane B(2), all of which were increased in the diabetic rat compared with age-matched nondiabetic rats. However, serum thromboxane B(2) levels were unchanged, confirming the selectivity of SC-58236 for COX-2. The renal protective effects of treatment of diabetic rats with the COX-2 inhibitor were reflected by a marked reduction in albuminuria, a reduction in kidney weight-to-body weight ratio, and TGF-β excretion and a marked decrease in the urinary excretion of TNF-α. The protective effects of SC-58236 were independent of changes in plasma glucose levels or serum advanced glycation end-product levels, which were not different from those of untreated diabetic rats. In an additional study, the inhibition of COX-2 with SC-58236 for 4 wk in diabetic rats resulted in creatinine clearance rates not different from those of control rats. These results confirm that the inhibition of COX-2 in the streptozotocin-diabetic rat confers renal protection and suggest that the induction of COX-2 precedes the increases in cytokines, TNF-α, and TGF-β.

Cyclooxygenase-2 in oncogenesis

Compelling experimental and clinical evidence supports the notion that cyclooxygenase-2, the inducible isoform of cyclooxygenase, plays a crucial role in oncogenesis. Clinical and epidemiological data indicate that aberrant regulation of cyclooxygenase-2 in certain solid tumors and hematological malignancies is associated with adverse clinical outcome. Moreover, findings extrapolated from experimental studies in cultured tumor cells and animal tumor models indicate that cyclooxygenase-2 critically influences all stages of tumor development from tumor initiation to tumor progression. Cyclooxygenase-2 elicits cell-autonomous effects on tumor cells resulting in stimulation of growth, increased cell survival, enhanced tumor cell invasiveness, stimulation of neovascularization, and tumor evasion from the host immune system. Additionally, the oncogenic effects of cyclooxygenase-2 stem from its unique ability to impact tumor cell surroundings and create a proinflammatory environment conducive for tumor development, growth and progression. The initial enthusiasm generated by the availability of cyclooxygenase-2 selective inhibitors for cancer prevention and therapy has been lessened by the severe cardiovascular adverse side effects associated with their long-term use, as well as by the mixed results of recent clinical trials evaluating the efficacy of cyclooxygenase-2 inhibitors in adjuvant chemotherapy. Therefore, our ability to efficiently target the oncogenic effects of cyclooxygenase-2 for therapeutic and preventive purposes strictly depends on a better understanding of the spatial and temporal aspects of its activation in tumor cells along with a clearer elucidation of the signaling networks whereby cyclooxygenase-2 affects tumor cells and their interactions with the tumor microenvironment. This knowledge has the potential of leading to the identification of novel cyclooxygenase-2-dependent molecular and signaling networks that can be exploited to improve cancer prevention and therapy.

[Expression and significance of COX-2 and its transcription factors NFAT3 and c-Jun in non-small cell lung cancer]

BACKGROUND AND OBJECTIVE

Cyclooxygenases (COX), the key enzymes in the conversion of arachidonic acid (AA) to prostaglandins (PGs), are involved in initiation and progression of cancer. The aim of this study is to explore the relationship between the expressions of COX-2 and several transcription factors in non-small cell lung cancer.

METHODS

Immunohistochemistry was performed to assay the expression levels of COX-2, c-Fos, c-Jun and nuclear factor of activated T cells 3 (NFAT3) in tissue microarray containing 159 tumor tissues of non-small cell lung cancer.

RESULTS

The positive rate of COX-2 expression was 42.8%, and the expression of COX-2 was significantly higher in squamous cell carcinoma than that in adenocarcinoma (52.9% vs 31.3%, χ²=7.723, P=0.005). The expression of COX-2 was significantly associated with differentiation grade, with the lower level in the poorer differentiation grade group (χ²=7.600, P=0.022). In this panel of samples, the expression of COX-2 was significantly correlated with c-Fos expression (r=0.456, P<0.001) and NFAT3 level (r=0.294, P<0.001). The correlation between the expressions of NFAT3 and c-Fos were also observed (r=0.231, P=0.003).

CONCLUSION

The expression of COX-2 was significantly associated with the expressions of transcription factors NFAT3 and c-Fos in nonsmall cell lung cancer.

Antinociceptive and anti-inflammatory properties of 7-hydroxycoumarin in experimental animal models: potential therapeutic for the control of inflammatory chronic pain

Objectives

In the present study we investigated the antinociceptive, anti-inflammatory and antipyretic effects of 7-hydroxycoumarin (7-HC) in animal models.

Methods

The effects of oral 7-HC were tested against acetic acid-induced writhing, formalin test, tail flick test, complete Freund's adjuvant (CFA)-induced hypernociception, carrageenan-induced paw oedema, lipopolysaccharide-induced fever and the rota rod test.

Key findings

7-HC (3–60 mg/kg) produced a dose-related antinociception against acetic acid-induced writhing in mice and in the formalin test. In contrast, treatment with 7-HC did not prevent thermal nociception in the tail flick test. A single treatment with 7-HC, 60 mg/kg, produced a long-lasting antinociceptive effect against CFA-induced hypernociception, a chronic inflammatory pain stimulus. Notably, at 60 mg/kg per day over 4 days the administration of 7-HC produced a continuous antinociceptive effect against CFA-induced hypernociception. 7-HC (30–120 mg/kg) produced anti-inflammatory and antipyretic effects against carrageenan-induced inflammation and lipopolysaccharide-induced fever, respectively. Moreover, 7-HC was found to be safe with respect to ulcer induction. In the rota rod test, 7-HC-treated mice did not show any motor performance alterations.

Conclusions

The prolonged antinociceptive and anti-inflammatory effects of 7-HC, in association with its low ulcerogenic activity, indicate that this molecule might be a good candidate for development of new drugs for the control of chronic inflammatory pain and fever.

Ex vivo effects of lysine clonixinate on cyclooxygenases in rat lung and stomach preparations

Lysine clonixinate (LC) is an anti-inflammatory, anti-pyretic and analgesic drug with minor digestive side effects, which might suggest a weak COX-1 inhibitor. The aim of this study focused on ex vivo effects of LC 40 mg/kg ip and indomethacin (INDO) 10 mg/kg ip in lung and stomach preparations of control rats and LPS-treated rats (5 mg/kg ip). The non-steroidal antiinflammatory drugs were administered concomitantly, following three hours and before one, two or three hours of LPS treatment. Tissues were weighed and incubated in 2 ml of Kress Ringer Bicarbonate buffer containing glucose (11 mM) under an atmosphere of 95% oxygen and 5% CO(2). Approximately 200 mg of tissue were used for each determination; 0.25 microCi of (14)C-arachidonic acid was added to each tube and the tissues were incubated for 60 min. Prostanoids were extracted from the incubation medium and separated by TLC. Results were expressed as a percentage of the total radioactivity of the plates (% of cpm on plate/100 mg ww). It was found that LC animals that were not given LPS did not modify the synthesis of PGE(2); in lung and stomach tissues showing that did not inhibit COX-1 activity. However, LC inhibited clearly the synthesis of PGE(2) in both preparations obtained from LPS-treated animals. The inhibition was shown when the rats were treated concomitantly, 3 h after or 1 or 2 h before the injection of LPS.

CCR1 and CCR5 chemokine receptors are involved in fever induced by LPS (E. coli) and RANTES in rats

This study, besides examining the involvement of CCR1 and CCR5 receptors in the LPS-induced fever (lipopolysaccharide, Escherichia coli) in male Wistar rats, evaluated if RANTES (regulated on activation, normal T cells expressed and secreted) injected into the preoptic area of the anterior hypothalamus (AH/POA) would promote an integrated febrile response via these receptors. Moreover, the effects of selective and non-selective cyclooxygenase blockers on both fever and the level of prostaglandin (PG)E(2) in the cerebrospinal fluid (CSF) after injection of RANTES into the AH/POA were also investigated. Met-RANTES, CCR1 and CCR5 receptor antagonist, reduced LPS-evoked fever dose dependently. RANTES microinjected into the AH/POA increased the rectal temperature of rats dose dependently and caused a significant decrease in the tail skin temperature and an increase (at 2.5 and 5 h) of the levels of PGE(2) in the CSF. Met-RANTES prevented the fever induced by RANTES. Ibuprofen abolished the fever caused by RANTES between 60 min and 2.5 h, and it reduced the temperature until the end of observation period. Celecoxib blocked the RANTES-induced fever, while indomethacin reduced it in the last 60 min of the experimental period. At 2.5 and 5 h all antipyretics brought the CSF PGE(2) level near to the control. These results indicate that CCR1 and CCR5 receptors are involved in the fever induced by systemic LPS and intrahypothalamic RANTES. RANTES promotes an integrated febrile response accompanied by an increase of CSF PGE(2). The inhibitory effects of celecoxib and ibuprofen suggest that PGE(2) was generated via COX-2. As indomethacin dissociates fever and the decrease of PGE(2) level during the RANTES-induced fever, an alternative COX-2-independent pathway or other mechanisms of action of celecoxib and ibuprofen might be considered.

Signal transduction underlying carbachol-induced PGE2 generation and cox-1 mRNA expression of rat brain

In this paper we have determined the different signal pathways involved in M(1) and M(3) muscarinic acetylcholine receptor (mAChR) dependent stimulation of cyclo-oxygenase 1 (cox-1) mRNA gene expression and PGE(2) production on rat cerebral frontal cortex. Carbachol stimulation of M(1) and M(3) mAChR exerts an increase in cox-1 mRNA gene expression without affecting cox-2 mRNA expression and increased PGE(2) generation. Besides, increased phosphoinositide (PI) turnover and stimulation of nitric oxide synthase (NOS) and cyclic GMP (cGMP) production. Inhibitors of phospholipase A(2) (PLA(2)), COX and phospholipase C (PLC), calcium/calmodulin (CaM), NOS and soluble guanylate cyclase prevent the carbachol effect. These results suggest that carbachol-activation of M(1) and M(3) mAChR increased PGE(2) release associated with an increased expression of cox-1 and NO-cGMP production. The mechanism appears to occur directly to PLC stimulation and indirectly to PLA(2) activation. These results may contribute to understand the effects and side effect of non-steroidal anti-inflammatory drugs in patients with cerebral degenerative diseases.

Reducing Clinically Significant Gastrointestinal Toxicity Associated with Nonsteroidal Antiinflammatory Drugs

OBJECTIVE:

To evaluate the efficacy of treatment strategies to reduce clinically significant gastrointestinal adverse effects associated with nonsteroidal antiinflammatory drugs (NSAIDs).

DATA SOURCES:

A MEDLINE search (1966–November 2003) was performed to identify relevant articles. Key search terms included proton-pump inhibitors, histamine H2 antagonists, misoprostol, cyclooxygenase-2 (COX-2) selective inhibitors, nonsteroidal antiinflammatory agents, stomach ulcer, prevention, and economics. Additional references were obtained from cross-referencing the bibliographies of selected articles.

STUDY SELECTION AND DATA EXTRACTION:

All information obtained from the MEDLINE search was reviewed. To provide the most clinically relevant information, only randomized controlled trials are included in this review.

DATA SYNTHESIS:

Clinically significant upper gastrointestinal adverse events, such as ulcers and ulcer complications, associated with NSAIDs are a cause of significant morbidity and mortality in the US. Interest in strategies to reduce the risk of these adverse events is high among clinicians and patients. Misoprostol, high-dose H2-receptor antagonists, proton-pump inhibitors, and COX-2 inhibitors have been shown to reduce this risk. Misoprostol and proton-pump inhibitors are more effective than H2-receptor antagonists; dose-related diarrhea limits the clinical utility of misoprostol. These strategies may not provide enough protection in patients taking concomitant low-dose aspirin therapy or patients with a history of ulcer complications.

CONCLUSIONS:

COX-2 inhibitors and proton-pump inhibitors are effective and well-tolerated therapies to reduce clinically significant upper gastrointestinal adverse events associated with NSAIDs.

Balancing Gastroprotection and Cardioprotection with Selective Cyclo-Oxygenase-2 Inhibitors

NSAIDs have been the mainstay of treatment in the management of pain and inflammation associated with chronic inflammatory disorders. They are effective. However, complications arising from chronic NSAID use are common and are primarily due to gastrointestinal (GI) toxicity in the form of gastritis, peptic erosions and ulceration and GI bleeds. GI toxicity has been attributed to the blockade of the cyclo-oxygenase (COX)-1-mediated generation of the cytoprotective prostanoids, such as prostaglandin (PG) E2 and PGI2 (prostacyclin). More recently, selective COX-2 inhibitors ('coxibs') were designed to inhibit the production of COX-2-dependent inflammatory prostanoids and to leave intact the cytoprotective COX-1 products. The coxibs, while exhibiting similar efficacy to traditional NSAIDs in controlled clinical trials of their efficacy in chronic inflammatory conditions, such as osteoarthritis and rheumatoid arthritis, have been associated with a reduced incidence of surrogate or actual indices of GI toxicity. However, concerns regarding cardiovascular safety in high-risk patients have evolved. These concerns were driven initially by the concept that inhibition of COX-2-derived endothelial PGI2 without concomitant inhibition of platelet thromboxane A2 would result in increased cardiovascular risk. This was borne out in the Vioxx Gastrointestinal Outcomes Research study of rofecoxib, but not demonstrated in the Celecoxib Long Term Arthritis Safety Study trial. Further elucidation of the relative roles of COX-1- and COX-2-generated prostanoids has enabled a greater understanding of the biology of these pathways. However, it is still not completely clear how this understanding may be appropriately translated into clinical medicine.

Pharmacodynamics and enantioselective pharmacokinetics of racemic carprofen in the horse

Carprofen is a nonsteroidal anti-inflammatory drug of the 2-arylpropionate subclass. It contains a single chiral centre and exists in two enantiomeric forms. In this study rac-carprofen, at two dosages, 0.7 and 4.0 mg/kg, and placebo were administered i.v. to six New Forest horses in a three period cross-over study. The concentration-time profiles were established for R(-) and S(+)-carprofen for plasma and both inflamed (exudate) and noninflamed (transudate) tissue cage fluids. R(-)-carprofen was the predominant enantiomer in all three fluids, as indicated by plasma area under the curve (AUC) values for R(-) and S(+)-carprofen of 117.4 and 22.6 microg h/mL (low dose carprofen) and 557.5 and 138.1 microg h/mL (high dose carprofen) respectively. Penetration of both enantiomers into exudate was slow and limited and passage into transudate was even lower. The pharmacodynamics of rac-carprofen was investigated at both the molecular level and in terms of the ability to suppress components of the tissue cage inflammatory response. Low dose carprofen produced only moderate and transient inhibition of serum thromboxane (Tx)B2 but failed to affect exudate prostaglandin (PG)E2 concentrations, whilst suppression of exudate leukotriene (LT)B4 and beta-glucuronidase was not significant. High dose carprofen produced greater and more persistent inhibition of serum TxB2 and virtually abolished exudate PGE2 synthesis. Some inhibition of LTB4 and beta-glucuronidase in exudate was also obtained. At both dosages rac-carprofen reduced the swelling produced by intradermal bradykinin injection but only high dose carprofen was anti-inflammatory as indicated by suppression of temperature rise over exudate tissue cages and neither dose affected leucocyte numbers in exudate. When considered in conjunction with previous data on carprofen, the present findings indicate that carprofen is not a selective inhibitor of cyclooxygenase (COX) isoenzymes, COX-1 and COX-2 in the horse, although it may show some preference for COX-2 inhibition. Because low dose carprofen, which is the clinically recommended dosage, produces minimal inhibition of COX, it is likely to achieve its therapeutic effects at least partially through other pathways, possibly including weak to moderate inhibition of 5-lipoxygenase and of enzyme release. The good safety margin of carprofen in clinical use might also be explained by weak COX inhibition and by other actions at the molecular level.

Selective inhibitors of cyclo-oxygenase-2 (COX-2) induce hypoalgesia in a rat paw model of inflammation

1. It is well-established that inhibitors of cyclo-oxygenase (COX) and hence of prostaglandin (PG) biosynthesis reverse inflammatory hyperalgesia and oedema in both human and animal models of inflammatory pain. 2. Paw oedema and hyperalgesia in rats were induced by injecting carrageenan (250 micro g paw(-1)) into a hindpaw. Both inflammatory responses were followed for 24 h after the injection, measuring hyperalgesia by decreased pain threshold in the paws and oedema by plethysmography. 3. Three selective inhibitors of cyclo-oxygenase-2 (COX-2), celecoxib, rofecoxib and SC 236, given systemically in a range of doses, before the inflammatory stimulus, abolished carrageenan-induced hyperalgesia with little reduction of oedema. These inhibitors also induced hypoalgesia, increasing nociceptive thresholds in the inflamed paw above normal, non-inflamed levels. This hypoalgesia was lost at the higher doses of the selective inhibitors, although hyperalgesia was still prevented. 4. In paws injected with saline only, celecoxib, given at the dose inducing the maximum hypoalgesia after carrageenan, did not alter the nociceptive thresholds. 5. Two non-selective inhibitors of COX-2, indomethacin and piroxicam, abolished hyperalgesia and reduced oedema but did not induce hypoalgesia. 6. Celecoxib given locally into the paw also abolished inflammatory hyperalgesia and induced hypoalgesia without reducing oedema. 7. We conclude that hypoalgesia is expressed only over a critical range of COX-2 inhibition and that concomitant inhibition of COX-1 prevents expression of hypoalgesia, although hyperalgesia is still prevented. 8 Our results suggest a novel anti-nociceptive pathway mediating hypoalgesia, involving COX-2 selectively and having a clear peripheral component. This peripheral component can be further explored for therapeutic purposes.

A comparative study of the effect of rofecoxib (a COX 2 inhibitor) and naproxen sodium on analgesic requirements after abdominal hysterectomy

This study evaluated the analgesic efficacy of administering preoperatively rofecoxib or naproxen sodium to patients undergoing abdominal hysterectomy. A randomized, double-blinded prospective study was conducted with 60 women undergoing elective abdominal hysterectomy under general anesthesia. Patients were randomly allocated into one of three equally sized groups. Patients in the first group received rofecoxib 50 mg 1 h before operation (group R), patient in the second group received naproxen sodium 550 mg 1 h before surgery (group N) and patients in the third group received a placebo tablet in the same time (group P). Total amount of used morphine mixture was higher in placebo group (93+/-6 ml) than in the group R (50+/-4 ml) and group N (64+/-6 ml). There were significant difference for total amount of used morphine mixture between group P and other two groups. There was significant difference in the volumes of morphine mixture used in the first 12 h in group P and other two groups. The occurrence of side effects such as, dyspepsia, epigastric discomfort, heartburn, were similar in group R and group P. However, this side effects were increased in group N. Rofecoxib receiving preoperatively was provided clinical efficacy for postoperative pain control and well tolerated for gastrointestinal side effects comparable with naproxen sodium.

Pharmacodynamics and pharmacokinetics of phenylbutazone in calves

Phenylbutazone (PBZ) was administered to six calves intravenously (i.v.) and orally at a dose rate of 4.4 mg/kg in a three-period cross-over study incorporating a placebo treatment to establish its pharmacokinetic and pharmacodynamic properties. Extravascular distribution was determined by measuring penetration into tissue chamber fluid in the absence of stimulation (transudate) and after stimulation of chamber tissue with the mild irritant carrageenan (exudate). PBZ pharmacokinetics after i.v. dosage was characterized by slow clearance (1.29 mL/kg/h), long-terminal half-life (53.4 h), low distribution volume (0.09 L/kg) and low concentrations in plasma of the metabolite oxyphenbutazone (OPBZ), confirming previously published data for adult cattle. After oral dosage bioavailability (F) was 66%. Passage into exudate was slow and limited, and penetration into transudate was even slower and more limited; area under curve values for plasma, exudate and transudate after i.v. dosage were 3604, 1117 and 766 microg h/mL and corresponding values after oral dosage were 2435, 647 and 486 microg h/mL. These concentrations were approximately 15-20 (plasma) and nine (exudate) times greater than those previously reported in horses (receiving the same dose rate of PBZ). In the horse, the lower concentrations had produced marked inhibition of eicosanoid synthesis and suppressed the inflammatory response. The higher concentrations in calves were insufficient to inhibit significantly exudate prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and beta-glucuronidase concentrations and exudate leucocyte numbers, serum thromboxane B2 (TxB2), and bradykinin-induced skin swelling. These differences from the horse might be the result of: (a) the presence in equine biological fluids of higher concentrations than in calves of the active PBZ metabolite, OPBZ; (b) a greater degree of binding of PBZ to plasma protein in calves; (c) species differences in the sensitivity to PBZ of the cyclo-oxygenase (COX) isoenzymes, COX-1 and COX-2 or; (d) a combination of these factors. To achieve clinical efficacy with single doses of PBZ in calves, higher dosages than 4.4 mg/kg will be probably required.

Polyunsaturated fatty acids (PUFA) and eicosanoids in human health and pathologies

Linoleic and alpha-linolenic acids, obtained from plant material in the diet are the precursors in tissues of two families with opposing effects which are referred to as "essential fatty acids" (EFA): arachidonic acid (AA) and pentaene (eicosapentaenoic acid: EPA) and hexaene (docosahexaenoic acid: DHA) acids. The role of EFA is crucial, without a source of AA or compounds which can be converted into AA, synthesis of prostaglandins (PGs) by a cyclooxygenase (COX) enzyme would be compromised, and this would seriously affect many normal metabolic processes. COX, also known as prostaglandin endoperoxide synthase (Pghs) or as prostaglandin G/H synthase, is a key membrane bound enzyme responsible for the oxidation of AA to PGs. Two COX isoforms have been identified, COX-1 and COX-2 that form PGH2, a common precursor for the biosynthesis of thromboxane A2 (TxA2), prostacyclin (PGI2) and PGs (PGD2, PGE2, PGF2alpha. COX-1 enzyme is expressed constitutively in most cells and tissues. Its expression remains constant under either physiological or pathological conditions controlling synthesis of those PGs primarily involved in the regulation of homeostatic functions. In contrast, COX-2 is an intermediate response gene that encodes a 71-kDa protein. COX-2 is normally absent from most cells but highly inducible in certain cells in response to inflammatory stimuli resulting in enhanced PG release. PGs formed by COX-2 primarily mediate pain and inflammation but have multiple effects that can favour tumorigenesis. They are more abundant in cancers than in normal tissues from which the cancers arise. COX-2 is a participant in the pathway of colon carcinogenesis, especially when mutation of the APC (Adenomatous Polyposis Coli) tumour suppressor gene is the initiating event. In addition, COX-2 up-regulation and elevated PGE2 levels are involved in breast carcinogenesis. It seems that there is a correlation between COX-2 level of expression and the size of the tumours and their propensity to invade underlying tissue. Inhibition by non-steroidal anti-inflammatory drugs (NSAIDs) of COX enzymes which significantly suppress PGE2 levels, reduced breast cancer incidence and protected against colorectal cancer. Therefore it is suggested that consumption of a diet enriched in n-3 PUFA (specifically EPA and DHA) and inhibition of COX-2 by NSAIDs may confer cardioprotective effects and provide a significant mechanism for the prevention and treatment of human cancers.

Cardiovascular pharmacology of nonselective nonsteroidal anti-inflammatory drugs and coxibs: clinical considerations

Cyclooxygenase (COX)-2 inhibitors have been developed with the goal of providing similar efficacy and greater safety compared with traditional nonsteroidal anti-inflammatory drugs. Development was based on the hypothesis that COX-1 is the housekeeping enzyme necessary for production of prostaglandins (PGs) with homeostatic functions, whereas COX-2 is a mediator of pathophysiologic processes. However, later research has demonstrated a role of COX-2 in production of PGs that have functions under normal physiologic conditions. In the vasculature, COX-2 seems to be the main enzyme responsible for the production of prostacyclin. Increased synthesis of this vasodilatory and antithrombotic PG represents a homeostatic response during periods of accelerated platelet-vessel wall interactions and counteracts increased synthesis of COX-1-derived prothrombotic prostanoid thromboxane A(2) (TXA(2)). The clinical sequelae of inhibiting prostacyclin activity in the absence of concomitant inhibition of TXA(2) are not currently clear. Animal studies show that inhibition of prostacyclin activity does not lead to spontaneous thrombosis but may increase response to thrombotic stimuli. Therefore, prostacyclin synthesis may be important for limiting thrombotic events in patients who are at an increased cardiovascular risk. Overviews of clinical studies in arthritis and Alzheimer's disease have not demonstrated increased cardiovascular risk associated with specific COX-2 inhibition in most patients. However, data from 1 clinical trial revealed a 5-fold divergence in rates of myocardial infarction between a coxib and a nonsteroidal anti-inflammatory drug comparitor. Credible explanations for the results of this trial have been proposed and further studies are necessary to clarify the relative risk-to-benefit ratio of COX-2 inhibition in patients at increased risk for cardiovascular events, and the effects of concomitant aspirin therapy.

An evidence-based evaluation of the gastrointestinal safety of coxibs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are nonselective inhibitors of cyclooxygenase (COX) isoforms COX-1 and COX-2. NSAIDs have analgesic and anti-inflammatory properties that are proven, and they are extensively used in the treatment of arthritis, pain, and headache. Despite their good efficacy, NSAIDs are associated with significant gastrointestinal (GI) toxicity, which appears to be related to the inhibition of the cytoprotective function of COX-1. Thus, selective COX-2 inhibitors, or coxibs, were designed to inhibit only the production of COX-2-dependent inflammatory prostaglandins, without any effect on COX-1 and its gastroprotective function. This article reviews important evidence on the GI safety of coxibs. Endoscopic studies demonstrated that coxibs, such as celecoxib and rofecoxib, induced significantly fewer ulcers than nonspecific NSAIDs. To analyze whether the incidence of clinical GI events is also lower with coxibs, 2 large controlled clinical trials, the Celecoxib Long-term Arthritis Safety Study (CLASS) and Vioxx Gastrointestinal Outcomes Research (VIGOR), evaluated the GI safety of celecoxib and rofecoxib, respectively. Based on evidence from the VIGOR trial, it was demonstrated that rofecoxib has already fulfilled the promise and significantly decreases the risk of clinically important and complicated GI events compared with a nonselective NSAID, naproxen. In contrast, the CLASS trial showed that the incidence of ulcer complications in patients treated with celecoxib was similar in patients treated with nonspecific NSAIDs.

Expression of cyclooxygenase enzymes in rat hypothalamo-pituitary-adrenal axis: effects of endotoxin and glucocorticoids

Prostaglandins play a key role in mediating the hypothalamo-pituitary-adrenocortical (HPA) responses to immune insults. This study aimed to provide some insight into the relative contributions of the constitutive and inducible forms of cyclooxygenase (COX-1 and COX-2) to the generation of these prostanoids by examining the effects of (1) endotoxin treatment on the expression of COX-1 and COX-2 mRNAs in the various components of the HPA axis in control and glucocorticoid pretreated rats, and (2) selective inhibition of COX-2 on the production of corticosterone by adrenal tissue in vitro. Endotoxin caused a marked rise in COX-2 mRNA in the adrenal gland that was evident 3 and 6 h after the injection and was prevented by pretreatment with dexamethasone. It also induced a modest increase in COX-2 mRNA in the hypothalamus but not in the hippocampus or anterior pituitary gland. By contrast, COX-1 mRNA was largely unaffected by the drug treatments in all tissues studied. In vitro the selective COX-2 inhibitor SC-236 caused a marked reduction in adrenocorticotropic hormone-driven corticosterone release, as did the nonselective COX inhibitor, indomethacin. These results support a role of COX-2 in the manifestation of the HPA responses to endotoxin, particularly within the adrenal gland.

Preoperative oral rofecoxib does not decrease postoperative pain or morphine consumption in patients after radical prostatectomy: a prospective, randomized, double-blinded, placebo-controlled trial

STUDY OBJECTIVES

To evaluate the analgesic efficacy of the rofecoxib po before radical prostatectomy.

DESIGN

Prospective, randomized, double-blinded, placebo-controlled trial.

SETTING

Teaching hospital.

PATIENTS

Anesthetic management was standardized. Patients received either a 50-mg rofecoxib capsule or a placebo capsule po 1 hour before induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Patient-generated 10-cm visual analog scale (VAS) scores for pain were assessed at 1, 2, 4, 6, 8, and 24 hours after surgery. Morphine consumption was recorded from a patient-controlled analgesia device at the same time. A patient-generated overall pain relief score was obtained at 24 hours after surgery. We were unable to detect any differences between study groups with respect to postoperative morphine consumption, VAS score, or overall pain relief score.

CONCLUSIONS

When rofecoxib is used po in maximum recommended doses before surgery, it does not provide significant analgesia that results in reduction in pain scores or analgesic requirements for patients after radical prostatectomy.

Cyclooxygenase inhibitors--current status and future prospects

Prostaglandins are formed from arachidonic acid by the action of cyclooxygenase and subsequent downstream synthetases. Two closely related forms of the cyclooxygenase have been identified which are now known as COX-1 and COX-2. Both isoenzymes transform arachidonic acid to prostaglandins, but differ in their distribution and their physiological roles. Meanwhile, the responsible genes and their regulation have been clarified. COX-1, the pre-dominantly constitutive form of the enzyme, is expressed throughout the body and performs a number of homeostatic functions such as maintaining normal gastric mucosa and influencing renal blood flow and platelet aggregation. In contrast, the inducible form is expressed in response to inflammatory and other physiological stimuli and growth factors, and is involved in the production of the prostaglandins that mediate pain and support the inflammatory process. All the classic NSAIDs inhibit both COX-1 and COX-2 at standard anti-inflammatory doses. The beneficial anti-inflammatory and analgesic effects are based on the inhibition of COX-2, but the gastrointestinal toxicity and the mild bleeding diathesis are a result of the concurrent inhibition of COX-1. Agents that inhibit COX-2 while sparing COX-1 represent a new attractive therapeutic development and could represent a major advance in the treatment of rheumatoid arthritis and osteoarthritis. Apart from its involvement in inflammatory processes, COX-2 seems to play a role in angiogenesis, colon cancer and Alzheimer's disease, based on the fact that it is expressed during these diseases. The benefits of specific and selective COX-2 inhibitors are currently under discussion and offer a new perspective for a further use of COX-2 inhibitors.

Maturation state determines the response of osteogenic cells to surface roughness and 1,25-dihydroxyvitamin D3

In this study we assessed whether osteogenic cells respond in a differential manner to changes in surface roughness depending on their maturation state. Previous studies using MG63 osteoblast-like cells, hypothesized to be at a relatively immature maturation state, showed that proliferation was inhibited and differentiation (osteocalcin production) was stimulated by culture on titanium (Ti) surfaces of increasing roughness. This effect was further enhanced by 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. In the present study, we examined the response of three additional cell lines at three different maturation states: fetal rat calvarial (FRC) cells (a mixture of multipotent mesenchymal cells, osteoprogenitor cells, and early committed osteoblasts), OCT-1 cells (well-differentiated secretory osteoblast-like cells isolated from calvaria), and MLO-Y4 cells (osteocyte-like cells). Both OCT-1 and MLO-Y4 cells were derived from transgenic mice transformed with the SV40 large T-antigen driven by the osteocalcin promoter. Cells were cultured on Ti disks with three different average surface roughnesses (Ra): PT, 0.5 microm; SLA, 4.1 microm; and TPS, 4.9 microm. When cultures reached confluence on plastic, vehicle or 10(-7) M or 10(-8) M 1,25(OH)2D3 was added for 24 h to all of the cultures. At harvest, cell number, alkaline phosphatase-specific activity, and production of osteocalcin, transforming growth factor beta1 (TGF-beta1) and prostaglandin E2 (PGE2) were measured. Cell behavior was sensitive to surface roughness and depended on the maturation state of the cell line. Fetal rat calvarial (FRC) cell number and alkaline phosphatase-specific activity were decreased, whereas production of osteocalcin, TGF-beta1, and PGE2 were increased with increasing surface roughness. Addition of 1,25(OH)2D3 to the cultures further augmented the effect of roughness for all parameters in a dose-dependent manner; only TGF-beta1 production on plastic and PT was unaffected by 1,25(OH)2D3. OCT-1 cell number and alkaline phosphatase (SLA > TPS) were decreased and production of PGE2, osteocalcin, and TGF-beta1 were increased on SLA and TPS. Response to 1,25(OH)2D3 varied with the parameter being measured. Addition of the hormone to the cultures had no effect on cell number or TGF-beta1 production on any surface, while alkaline phosphatase was stimulated on SLA and TPS; osteocalcin production was increased on all Ti surfaces but not on plastic; and PGE2 was decreased on plastic and PT, but unaffected on SLA and TPS. In MLO-Y4 cultures, cell number was decreased on SLA and TPS; alkaline phosphatase was unaffected by increasing surface roughness; and production of osteocalcin, TGF-beta1, and PGE2 were increased on SLA and TPS. Although 1,25(OH)2D3 had no effect on cell number, alkaline phosphatase, or production of TGF-beta1 or PGE2 on any surface, the production of osteocalcin was stimulated by 1,25(OH)2D3 on SLA and TPS. These results indicate that surface roughness promotes osteogenic differentiation of less mature cells, enhancing their responsiveness to 1,25(OH)2D3. As cells become more mature, they exhibit a reduced sensitivity to their substrate but even the terminally differentiated osteocyte is affected by changes in surface roughness.

A pharmacodynamic and pharmacokinetic study with vedaprofen in an equine model of acute nonimmune inflammation

The pharmacodynamics and enantioselective pharmacokinetics of vedaprofen were studied in six ponies in a two period cross-over study, in which a mild acute inflammatory reaction was induced by carrageenan soaked sponges implanted subcutaneously in the neck. Vedaprofen, administered intravenously at a dosage of 1 mg/kg, produced significant and prolonged inhibition of ex vivo serum thromboxane B2 (TXB2) synthesis and short-lived inhibition of exudate prostaglandin E2 (PGE2) and TXB2 synthesis. Vedaprofen also partially inhibited oedematous swelling and leucocyte infiltration into exudate. Vedaprofen displayed enantioselective pharmacokinetics, plasma concentrations of the R(-) enantiomer exceeding those of S(+) vedaprofen. The plasma concentration ratio, R:S, increased from 69:31 at 5 min to 96:4 at 3 h and plasma mean AUC values were 7524 and 1639 ng x h/mL, respectively. Volume of distribution was greater for S(+) vedaprofen, whilst elimination half-life (t(1/2beta)) and mean residence time were greater for R(-) vedaprofen. The penetration of vedaprofen into inflammatory exudate was also enantioselective. For R(-) and S(+) vedaprofen maximum concentration (Cmax) values were 2950 and 1534 ng/mL, respectively, and corresponding AUC values were 9755 and 4400 ng x h/mL. Vedaprofen was highly protein bound (greater than 99%) in both plasma and exudate. The significance of these data for the therapeutic use of vedaprofen is discussed.

Substituted heterocyclic analogs as selective COX-2 inhibitors in the flosulide class

Substituted heterocyclic analogs in the Flosulide class were investigated as potential selective cyclooxygenase-2 inhibitors. 6-(4-Ethyl-2-thiazolylthio)-5-methanesulfonamido-3H-isobe nzofuran-1-one 14 was found to be the optimal compound in the series with superior in vitro and in vivo activities.

The induction of pain: an integrative review

The highly disagreeable sensation of pain results from an extraordinarily complex and interactive series of mechanisms integrated at all levels of the neuroaxis, from the periphery, via the dorsal horn to higher cerebral structures. Pain is usually elicited by the activation of specific nociceptors ('nociceptive pain'). However, it may also result from injury to sensory fibres, or from damage to the CNS itself ('neuropathic pain'). Although acute and subchronic, nociceptive pain fulfils a warning role, chronic and/or severe nociceptive and neuropathic pain is maladaptive. Recent years have seen a progressive unravelling of the neuroanatomical circuits and cellular mechanisms underlying the induction of pain. In addition to familiar inflammatory mediators, such as prostaglandins and bradykinin, potentially-important, pronociceptive roles have been proposed for a variety of 'exotic' species, including protons, ATP, cytokines, neurotrophins (growth factors) and nitric oxide. Further, both in the periphery and in the CNS, non-neuronal glial and immunecompetent cells have been shown to play a modulatory role in the response to inflammation and injury, and in processes modifying nociception. In the dorsal horn of the spinal cord, wherein the primary processing of nociceptive information occurs, N-methyl-D-aspartate receptors are activated by glutamate released from nocisponsive afferent fibres. Their activation plays a key role in the induction of neuronal sensitization, a process underlying prolonged painful states. In addition, upon peripheral nerve injury, a reduction of inhibitory interneurone tone in the dorsal horn exacerbates sensitized states and further enhance nociception. As concerns the transfer of nociceptive information to the brain, several pathways other than the classical spinothalamic tract are of importance: for example, the postsynaptic dorsal column pathway. In discussing the roles of supraspinal structures in pain sensation, differences between its 'discriminative-sensory' and 'affective-cognitive' dimensions should be emphasized. The purpose of the present article is to provide a global account of mechanisms involved in the induction of pain. Particular attention is focused on cellular aspects and on the consequences of peripheral nerve injury. In the first part of the review, neuronal pathways for the transmission of nociceptive information from peripheral nerve terminals to the dorsal horn, and therefrom to higher centres, are outlined. This neuronal framework is then exploited for a consideration of peripheral, spinal and supraspinal mechanisms involved in the induction of pain by stimulation of peripheral nociceptors, by peripheral nerve injury and by damage to the CNS itself. Finally, a hypothesis is forwarded that neurotrophins may play an important role in central, adaptive mechanisms modulating nociception. An improved understanding of the origins of pain should facilitate the development of novel strategies for its more effective treatment.

Bradykinin Stimulates IL-8 Production in Cultured Human Airway Smooth Muscle Cells: Role of Cyclooxygenase Products

IL-8 is an important neutrophil and eosinophil chemoattractant in asthma. A recent report has suggested that bradykinin (BK), an asthmatic mediator, induces the release of IL-8 in nonairway cells. We have recently reported that BK causes cyclooxygenase (COX)-2 induction and PGE2 release in human airway smooth muscle (ASM) cells. In this study, we tested the ability of BK to induce IL-8 from these cells and explored the role of COX products and COX-2 induction in this process. Confluent serum-deprived human ASM cells were studied. IL-8 was assayed by specific ELISA. Unstimulated cells released low levels of IL-8. BK enhanced IL-8 release in a concentration- and time-dependent fashion (maximum 50-fold increase over basal). The nonselective COX inhibitor indomethacin and the selective COX-2 inhibitor NS-398 strongly inhibited BK-stimulated PGE2 and IL-8 production. The COX substrate arachidonic acid also caused PGE2 and IL-8 production, and its effect was inhibited by nonselective COX inhibitors but unaffected by NS-398. Both the BK- and arachidonic acid-induced IL-8 production was inhibited by the protein synthesis inhibitors cycloheximide and actinomycin D and by the steroid dexamethasone. Furthermore, exogenous PGE2 and calcium ionophore A23187 also stimulated IL-8 release. BK-induced IL-8 release was mimicked by the BK B2 receptor agonist (Tyr(Me)8)-BK and was potently inhibited by the selective B2 receptor antagonist HOE-140. These results suggest that human ASM can be a source of IL-8 and also that endogenous prostanoids, involving both COX-1 and COX-2, have a novel role in mediating BK-induced IL-8 production.

Impaired cAMP production in human airway smooth muscle cells by bradykinin: role of cyclooxygenase products

Interleukin (IL)-1beta impairs human airway smooth muscle (ASM) cell cAMP responses to isoproterenol (Iso). We investigated if bradykinin (BK) could cause a similar effect and the role of cyclooxygenase (COX) products in this event, since we have recently reported that BK, like IL-1beta, also causes COX-2 induction and prostanoid release in human ASM cells. BK pretreatment significantly attenuated Iso-induced cAMP generation in a time- and concentration-dependent manner. cAMP generation by prostaglandin (PG) E2 but not by forskolin was also impaired. The COX inhibitor indomethacin completely prevented the impairment, whereas the selective COX-2 inhibitors NS-398 and nimesulide, protein synthesis inhibitors cycloheximide and actinomycin D, and steroid dexamethasone were all partially effective. The impairment was mimicked by the B2 agonist [Tyr(Me)8]BK, the Ca2+ ionophore A-23187, and PGE2 and prevented by the B2 antagonist HOE-140, but anti-IL-1beta serum was ineffective. The results indicate that BK impairs human ASM cell responses to Iso, and the effect is largely mediated by B2 receptor-related COX product release via both COX isoforms and is independent of IL-1beta.

Contribution of cyclooxygenase-1 and cyclooxygenase-2 to prostanoid formation by human enterocytes stimulated by calcium ionophore and inflammatory agents

The stimulation of intestinal epithelial cell cyclooxygenase (COX) enzymes with inflammatory agents and the inhibition of COX-1 and COX-2 enzymes has the potential to increase understanding of the role of these enzymes in intestinal inflammation. The aim of this study was to determine the contributions of COX-1 and -2 to the production of specific prostanoids by unstimulated and stimulated intestinal epithelial cells. Cultured enterocytes were stimulated with lipopolysaccharide (LPS), interleukin-1 (IL-1)beta (IL-1 beta), and calcium ionophore (Ca Ion), with and without COX inhibitors. Valerylsalicylic acid (VSA) was employed as the COX-1 inhibitor, and SC-58125 and NS398 were used as the COX-2 inhibitors. Prostanoids were quantitated by Elisa assay. Western immunoblotting demonstrated the presence of constitutive COX-1 and inducible COX-2 enzyme. Unstimulated prostanoid formation was not decreased by the COX-1 inhibitor. All of the stimulants evaluated increased prostaglandin E2 (PGE2) production. Only Ca Ion stimulated prostaglandin D2 (PGD2) production while IL-1 beta, and Ca Ion, but not LPS, increased prostaglandin F2 alpha (PGF2 alpha) formation. Ca Ion-stimulated prostanoid formation was uniformly inhibited by COX-2, but not COX-1, inhibitors. IL-1 beta-stimulated PGE2 and PGE2 alpha formation was significantly decreased by both COX-1 and COX-2 inhibitors. VSA, in a dose-dependent manner, significantly decreased IL-1 beta-stimulated PGE2 and PGF2 alpha production. Unstimulated prostanoid formation was not dependent on constitutive COX-1 activity. The stimulation of intestinal epithelial cells by Ca Ion seemed to uniformly produce prostanoids through COX-2 activity. There was no uniform COX-1 or COX-2 pathway for PGE and PGF2 alpha formation stimulated by the inflammatory agents, suggesting that employing either a COX-1 or COX-2 inhibitor therapeutically will have varying effects on intestinal epithelial cells dependent on the prostanoid species and the inflammatory stimulus involved.

Cyclooxygenases 1 and 2

Cyclooxygenase (COX), first purified in 1976 and cloned in 1988, is the key enzyme in the synthesis of prostaglandins (PGs) from arachidonic acid. In 1991, several laboratories identified a product from a second gene with COX activity and called it COX-2. However, COX-2 was inducible, and the inducing stimuli included pro-inflammatory cytokines and growth factors, implying a role for COX-2 in both inflammation and control of cell growth. The two isoforms of COX are almost identical in structure but have important differences in substrate and inhibitor selectivity and in their intracellular locations. Protective PGs, which preserve the integrity of the stomach lining and maintain normal renal function in a compromised kidney, are synthesized by COX-1. In addition to the induction of COX-2 in inflammatory lesions, it is present constitutively in the brain and spinal cord, where it may be involved in nerve transmission, particularly that for pain and fever. PGs made by COX-2 are also important in ovulation and in the birth process. The discovery of COX-2 has made possible the design of drugs that reduce inflammation without removing the protective PGs in the stomach and kidney made by COX-1. These highly selective COX-2 inhibitors may not only be anti-inflammatory but may also be active in colon cancer and Alzheimer's disease.

Immunopharmacology of human mast cells and basophils

Human mast cells and basophils play a key role in the pathogenesis of several immunological and inflammatory disorders, not only by producing inflammatory and fibrogenic mediators, but also by directly (CD40 ligand) and indirectly secreting various cytokines and chemokines. Studies carried out to evaluate the effects of drugs that modulate the release of mediators and cytokines from these cells have contributed to clarifying the biochemical mechanism by which immunological and non-immunological stimuli activate these cells. Significant differences have been documented between human mast cells and basophils as regard the pharmacological agents that modulate the release of mediators, between mast cells isolated from different anatomical sites, and between compounds of the same class of drugs. Efforts to gain insight into the biochemical events occurring during immunological activation of mast cells and basophils could lead to the identification of new biochemical targets for therapeutic interventions in several immunological disorders.