Involvement of Cyclooxygenase-2 in Establishing an Immunosuppressive Microenvironment in Tumorspheres Derived from TMZ-Resistant Glioblastoma Cell Lines and Primary Cultures.

Glioblastoma (GBM) is characterized by an immunosuppressive tumor microenvironment (TME) strictly associated with therapy resistance. Cyclooxygenase-2 (COX-2) fuels GBM proliferation, stemness, and chemoresistance. We previously reported that COX-2 upregulation induced by temozolomide (TMZ) supported chemoresistance. Also, COX-2 transfer by extracellular vesicles released by T98G promoted M2 polarization in macrophages, whereas COX-2 inhibition counteracted these effects. Here, we investigated the COX-2 role in the stemness potential and modulation of the GBM immunosuppressive microenvironment. The presence of macrophages U937 within tumorspheres derived from GBM cell lines and primary cultures exposed to celecoxib (COX-2 inhibitor) with or without TMZ was studied by confocal microscopy. M2 polarization was analyzed by TGFß-1 and CD206 levels. Osteopontin (OPN), a crucial player within the TME by driving the macrophages' infiltration, and CD44 expression was assessed by Western blot. TMZ strongly enhanced tumorsphere size and induced the M2 polarization of infiltrating macrophages. In macrophage-infiltrated tumorspheres, TMZ upregulated OPN and CD44 expression. These TMZ effects were counteracted by the concurrent addition of CXB. Remarkably, exogenous prostaglandin-E2 restored OPN and CD44, highlighting the COX-2 pivotal role in the protumor macrophages' state promotion. COX-2 inhibition interfered with TMZ's ability to induce M2-polarization and counteracted the development of an immunosuppressive TME.

Pharmacokinetic evaluation of oral deracoxib in geese (Anser anser domesticus).

The integration of pain management in veterinary practice, driven by heightened animal welfare concerns, extends to avian species where subtle and nonspecific behavioral signs pose challenges. Given that safety concerns with classical NSAIDs highlight the need for more targeted alternatives in birds, this study explores the pharmacokinetic (PK) properties of Deracoxib (DX), a COX-2 selective NSAID approved for use in dogs, following a single oral administration in geese. Six healthy female geese received 4 mg/kg DX. Blood was drawn from the left wing vein to heparinized tubes at 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6, 8, 10, and 24 h. Plasma DX concentrations were measured using HPLC coupled to an UV detector, and the data were pharmacokinetically analyzed using PKanalix™ software in a non-compartmental approach. The results indicated a terminal half-life of 6.3 h and a Tmax of 1 h, with no observed adverse effects. While refraining from claiming absolute safety based on a single dose, it is worth highlighting that further safety studies for DX in geese are warranted, suggesting a possibility for intermittent use. In addition, drawing conclusions on efficacy and suitability awaits further research, particularly in understanding COX-2 selectivity and protein binding characteristics specific to geese.

Disposition kinetics of robenacoxib following intravenous and oral administration in geese (Anser anser domesticus).

Robenacoxib (RX) is a veterinary cyclooxygenase-2 selective inhibitor drug. It has never been tested on birds and is only labelled for use in cats and dogs. The purpose of this study was to assess its pharmacokinetics in geese after single intravenous (IV) and oral (PO) administrations. Four-month healthy female geese (n = 8) were used. Geese were subjected to a two-phase, single-dose (2 mg/kg IV, 4 mg/kg PO), open, longitudinal study design with a four-month washout period between the IV and the PO phases. Blood was collected from the left wing vein to heparinized tubes at 0, 0.085 (for IV only), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6, 8, 10, and 24 h. Plasma RX concentrations were measured using HPLC coupled to an UV detector, and the data were pharmacokinetically analysed using ThothPro™ 4.3 software in a non-compartmental approach. Following IV administration, terminal elimination half-life, volume of distribution, and total clearance were 0.35 h, 0.34 L/kg, and 0.68 L/h/kg, respectively. For the PO route, the mean peak plasma concentration was 6.78 µg/mL at 0.50 h. The t1/2λz was very short and significantly different between the IV and PO administrations (0.35 h IV vs. 0.99 h PO), suggesting the occurrence of a flip-flop phenomenon. The Cl values corrected for the F% were significantly different between IV and PO administrations. It might have been a consequence of the longitudinal study design and the altered physiological and environmental conditions after a 4-month washout period. The absolute oral F% computed with the AUC method surpassed 150%, but after normalizing it to t1/2λz, it was 46%. In conclusion, the administration of RX might not be suitable for geese, due to its short t1/2λz.

Effect of Firocoxib and Flunixin Meglumine on Large Colon Mural Thickness of Healthy Horses.

Nonsteroidal anti-inflammatory drug (NSAID) administration carries risks of gastrointestinal toxicity. Selective COX-2 inhibitors ("coxibs") were designed to reduce risks of adverse effects but are still associated with gastrointestinal complications in humans. The effect of coxibs on colonic inflammation and integrity in horses is unknown. The study objective was to compare the effects of the coxib firocoxib and the nonselective NSAID flunixin meglumine on ultrasonographic indicators of colonic inflammation in healthy horses. Twelve healthy adult horses were administered flunixin meglumine (1.1 mg/kg IV q12h) and omeprazole (1 mg/kg PO q24h) for 5 days, allowed a 6-month washout period, then administered firocoxib (0.3 mg/kg PO once, then 0.1 mg/kg PO q24h for 4 days) and omeprazole. Transabdominal ultrasonographic examination and serum chemistry profiles were performed at the beginning and end of each treatment week. Colon wall thickness increased over time when horses received firocoxib (median post treatment 5.8 mm, interquartile range 2.8 mm; P < .001), but not flunixin (median 3 mm, interquartile range 1.2 mm; P = .7) and was significantly greater following firocoxib compared to flunixin (P = .003). Subjectively, colonic edema was noted more frequently following treatment with firocoxib (11/12 horses), compared to flunixin (1/12 horses). There were no clinically significant alterations in hematologic parameters after administration of either drug. The increase in colon wall thickness following treatment with the COX-2 selective NSAID firocoxib may suggest a risk of subclinical colitis in healthy horses. Monitoring colonic health when NSAIDs are used in a clinical setting is warranted.

Synopsis of the pharmacokinetics, pharmacodynamics, applications, and safety of firocoxib in horses.

According to in vitro and in vivo investigations, firocoxib (FX), a second-generation coxib, is a highly selective COX-2 inhibitor in horses. With a COX-1/COX-2 IC50 ratio of 643 in horses, FX spares the COX-1 inhibitory effects. It is approved for the treatment of musculoskeletal problems and lameness in horses and dogs with osteoarthritis (OA). For the treatment of OA in horses, both an injectable formulation for IV administration at a dose of 0.09 mg/kg for five days and an oral paste formulation at a dose of 0.1 mg/kg for 14 days are licensed. Numerous analytical methods were reported in the literature to quantify FX in biological fluids, using HPLC and LC-MS. FX presents remarkable pharmacokinetics and pharmacodynamics compared to other coxibs. It has an oral bioavailability of 80% or higher and is effectively absorbed by horses. Its volume of distribution is around 2 L/kg, and it is slowly eliminated. Due to the long elimination half-life (around 2 days), which allows a once daily dosing, a single 0.3 mg/kg loading dose has been recommended. This enables the establishment of steady-state drug concentrations within 24 h, making it appropriate for acute treatment as well. Its IC80 is equal to 103 ng/mL in whole blood and, with an EC50 of 27 ng/mL, it has the highest affinity for its receptor compared to the other commonly administered NSAIDs in horses.

Cyclooxygenase-2 Upregulated by Temozolomide in Glioblastoma Cells Is Shuttled In Extracellular Vesicles Modifying Recipient Cell Phenotype.

Temozolomide (TMZ) resistance is frequent in patients with glioblastoma (GBM), a tumor characterized by a marked inflammatory microenvironment. Recently, we reported that cyclooxygenase-2 (COX-2) is upregulated in TMZ-resistant GBM cells treated with high TMZ concentrations. Moreover, COX-2 activity inhibition significantly counteracted TMZ-resistance of GBM cells. Extracellular vesicles (EV) are considered crucial mediators in orchestrating GBM drug resistance by modulating the tumor microenvironment (TME) and affecting the surrounding recipient cell phenotype and behavior. This work aimed to verify whether TMZ, at low and clinically relevant doses (5-20 µM), could induce COX-2 overexpression in GBM cells (T98G and U87MG) and explore if secreted EV shuttled COX-2 to recipient cells. The effect of COX-2 inhibitors (COXIB), Celecoxib (CXB), or NS398, alone or TMZ-combined, was also investigated. Our results indicated that TMZ at clinically relevant doses upregulated COX-2 in GBM cells. COXIB treatment significantly counteracted TMZ-induced COX-2 expression, confirming the crucial role of the COX-2/PGE2 system in TMZ-resistance. The COXIB specificity was verified on U251MG, COX-2 null GBM cells. Western blotting of GBM-EV cells showed the COX-2 presence, with the same intracellular trend, increasing in EV derived from TMZ-treated cells and decreasing in those derived from COXIB+TMZ-treated cells. We then evaluated the effect of EV secreted by TMZ-treated cells on U937 and U251MG, used as recipient cells. In human macrophage cell line U937, the internalization of EV derived by TMZ-T98G cells led to a shift versus a pro-tumor M2-like phenotype. On the other hand, EV from TMZ-T98G induced a significant decrease in TMZ sensitivity in U251MG cells. Overall, our results, in confirming the crucial role played by COX-2 in TMZ-resistance, provide the first evidence of the presence and effective functional transfer of this enzyme through EV derived from GBM cells, with multiple potential consequences at the level of TME.

Robenacoxib pharmacokinetics in sheep following oral, subcutaneous, and intravenous administration.

The aim of this study was to evaluate the pharmacokinetics (PK) of robenacoxib (RX), a COX-2 selective non-steroidal anti-inflammatory drug, in sheep after single subcutaneous (SC), oral (PO), and intravenous (IV) administration. Five healthy female sheep underwent a three-phase parallel study design with a washout period of 4 weeks, in which sheep received a 4 mg/kg SC dose in phase 1, a 4 mg/kg PO administration in phase 2, and a 2 mg/kg IV administration in phase 3. Plasma RX concentrations were measured over a 48 h period for each treatment using HPLC coupled to a UV multiple wavelength detector, and the PK parameters were estimated using a non-compartmental method. Following IV administration, terminal elimination half-life, volume of distribution at steady state, and total clearance were 2.64 h, 0.077 L/kg, and 0.056 L/h kg, respectively. The mean peak plasma concentrations following SC and PO administrations were 7.04 and 3.01 µg/mL, respectively. The mean bioavailability following SC and PO administrations were 45.98% and 16.58%, respectively. The SC route may be proposed for use in sheep. However, the multi-dose and pharmacodynamic studies are necessary to establish more accurately its safety and efficacy in sheep.

Cyclooxygenase-2 Inhibition as an Add-On Strategy in Drug Resistant Epilepsy-A Canine Translational Study.

Drug-resistant epilepsy is a common complaint in dogs and affects up to 30% of dogs with idiopathic epilepsy. Experimental data suggest that targeting cyclooxygenase-2 (COX-2) mediated signaling might limit excessive excitability and prevent ictogenesis. Moreover, the role of COX-2 signaling in the seizure-associated induction of P-glycoprotein has been described. Thus, targeting this pathway may improve seizure control based on disease-modifying effects as well as enhancement of brain access and efficacy of the co-administered antiseizure medication. The present open-label non-controlled pilot study investigated the efficacy and tolerability of a COX-2 inhibitor (firocoxib) add-on therapy in a translational natural occurring chronic epilepsy animal model (client-owned dogs with phenobarbital-resistant idiopathic epilepsy). The study cohort was characterized by frequent tonic-clonic seizures and cluster seizures despite adequate phenobarbital treatment. Enrolled dogs (n = 17) received a firocoxib add-on therapy for 6 months. Tonic-clonic seizure and cluster seizure frequencies were analyzed at baseline (6 months) months during the study (6 months). The responders were defined by a substantial reduction of tonic-clonic seizure and cluster seizure frequency (≥50%). In total, eleven dogs completed the study and were considered for the statistical analysis. Two dogs (18%, 2/11) were classified as responders based on their change in seizure frequency. Interestingly, those two dogs had the highest baseline seizure frequency. The overall tolerability was good. However, given the low percentage of responders, the present data do not support an overall considerable efficacy of COX-2 inhibitor add-on therapy to overcome naturally occurring phenobarbital-resistant epilepsy in dogs. Further translational evaluation should only be considered in the canine patients with a very high baseline seizure density.

Pharmacology, safety, efficacy and clinical uses of the COX-2 inhibitor robenacoxib.

Robenacoxib is a veterinary-approved non-steroidal anti-inflammatory drug (NSAID) of the coxib group. It possesses anti-hyperalgesic, anti-inflammatory and anti-pyretic properties. Robenacoxib inhibits the cyclooxygenase (COX)-2 isoform of COX selectively (in vitro IC50 ratios COX-1:COX-2, 129:1 in dogs, 32:1 in cats). At registered dosages (2 mg/kg subcutaneously in dogs and cats, 1-4 mg/kg orally in dogs and 1-2.4 mg/kg orally in cats), robenacoxib produces significant inhibition of COX-2 whilst sparing COX-1. The pharmacokinetic (PK) profile of robenacoxib is characterized by a high degree of binding to plasma proteins (>98%) and moderate volume of distribution (at steady state, 240 ml/kg in dogs and 190 ml/kg in cats). In consequence, the terminal half-life in blood (<2 h) is short, despite moderate body clearance (0.81 L/kg/h) in dogs and low clearance (0.44 L/kg/h) in cats. Excretion is principally in the bile (65% in dogs and 72% in cats). Robenacoxib concentrates in inflamed tissues, and clinical efficacy is achieved with once-daily dosing, despite the short blood terminal half-life. In dogs, no relevant breed differences in robenacoxib PK have been detected. Robenacoxib has a wide safety margin; in healthy laboratory animals daily oral doses 20-fold (dog, 1 month), eight-fold (cat, 6 weeks) and five-fold (dog, 6 months) higher than recommended clinical doses were well tolerated. Clinical efficacy and safety have been demonstrated in orthopaedic and soft tissue surgery, and in musculoskeletal disorders in dogs and cats.

Discovery of pyrazole N-aryl sulfonate: A novel and highly potent cyclooxygenase-2 (COX-2) selective inhibitors.

Based on a new pyrazole sulfonate synthetic method, a novel class of molecules with a basic structure of pyrazole N-aryl sulfonate have been designed and synthesized. The interest in conducting intensive research stems from quite evident anti-inflammatory effects exhibited by the compounds in preliminary animal experiments. A series of compounds were synthesized by different substitutions of the R1, R2, and R3 groups. Within the series, 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and phenyl 5-methyl-3-(4-(trifluoromethyl) phenyl)-1H-pyrazole-1-sulfonate exhibited excellent anti-inflammatory activity (% inhibition of auricular edemas = 27.0 and 35.9, respectively); the in vivo analgesic activity of phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate was confirmed to be effective (inhibition ratio of writhing = 50.7% and 48.5% separately), and compounds phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate , 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate were identified as selective COX-2 inhibitors (SI = 455, 10,497 and >189 severally). In Acute Oral Toxicity assays conducted in vivo, the lethal dose 50 (LD50) of 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate to mice was >2000 mg/kg BW.

Clinical safety of robenacoxib in cats with chronic musculoskeletal disease.

BACKGROUND: Evaluate the clinical safety of robenacoxib in cats with chronic musculoskeletal disease (CMSD). ANIMALS: Four hundred forty-nine client-owned cats with CMSD. METHODS: Pooled analysis of safety variables from 4 prospective randomized blinded clinical trials of robenacoxib (n = 222) versus placebo (n = 227), administered orally once daily for 4 to 12 weeks. Safety was evaluated from reported adverse events (AEs) and abnormalities detected on hematology and serum and urine chemistry analyses. RESULTS: The number of cats with at least 1 AE was not significantly different (P = .15) with robenacoxib (n = 106, 47.8%) compared to placebo (n = 93, 41.0%). The relative risk of at least 1 AE (incidence robenacoxib/placebo) was 1.15 (95% confidence interval 0.93-1.43). There was no significant difference between groups in the number of clinical signs (range, 0-9) per cat (P = .23). Serum creatinine concentrations were higher during robenacoxib administration compared to placebo (+4.36 µmol/L, 95% confidence interval 0.21-8.50), but no related adverse clinical effects were detected. In the subgroup of 126 cats with evidence of chronic kidney disease, the relative risk of at least 1 AE (robenacoxib/placebo) was 1.09 (95% confidence interval 0.78-1.52, P = .61). CONCLUSIONS AND CLINICAL IMPORTANCE: Robenacoxib was not associated with increased risk of AEs compared to placebo when administered for 4 to 12 weeks to cats with CMSD. The generalizability of the results to general practice is limited by the fact that cases with severe and uncontrolled concomitant diseases were not included.

Revisión del tratamiento farmacológico del dolor secundario a artrosis con paracetamol, antinflamatorios no esteroideos clásicos (AINE) y los inhibidores selectivos de la ciclooxigenasa tipo 2 (COXIB) / Review of the pharmacological treatment of osteoarthritis pain with paracetamol, non-steroid anti-inflammatory (NSAIDSS) and selective cyclooxygenase-2 inhibitors (COXIB)

En este monográfico se realiza una revisión de todos los aspectos relacionados con la artrosis para poder ofrecer al/la paciente el manejo más óptimo a la luz de la bibliografía disponible en el momento de redacción del mismo. En este artículo en concreto realizamos una revisión bibliográfica del tratamiento farmacológico de la artrosis con paracetamol, antinflamatorios no esteroideos clásicos (AINE) e inhibidores selectivos de la ciclooxigenasa tipo 2 (COXIB). Actualizamos los aspectos que más nos interesan desde un punto de vista clínico: eficacia, seguridad, comparativa dentro de estas opciones y con el resto de alternativas (intervencionistas u otras farmacológicas), para poder decidir los perfiles de pacientes en los que puede estar indicado este tipo de opciones farmacológicas, el momento evolutivo de su enfermedad o incluso el tiempo de mantenimiento de este tipo de fármacos. Para ello hemos realizado una revisión bibliográfica de los estudios que evalúan el efecto de estos fármacos analgésicos en la artrosis mediante una búsqueda electrónica utilizando Google Scholar, Medline/PubMed y la base de datos Cochrane de revisiones sistemáticas con el fin de recopilar la literatura disponible entre los años 2000 y 2020.(AU)

In this monograph, a review of all aspects related to osteoarthritis is carried out in order to offer the patient with osteoarthritis the most optimal management in light of the bibliography available at the time of writing. In this specific article, we made a bibliographic review of the pharmacological treatment of osteoarthritis with paracetamol, classical non-steroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase type 2 inhibitors (COXIBS). We update the aspects that interest us most from a clinical point of view: efficacy, safety, comparison within these options and with the rest of the alternatives (interventional or other pharmacological) for being able to decide the patient profiles in which this type is indicated of pharmacological options, the evolutionary moment of the disease or even the maintenance time of this type of drug. For reaching our objective, we have carried out a bibliographic review of the studies evaluating the effect of these analgesic drugs in osteoarthritis with an electronic search using Google Scholar, Medline/PubMed and the Cochrane database of systematic reviews to compile the available literature between the years 2000 and 2020.(AU)

Combatting joint pain and inflammation by dual inhibition of monoacylglycerol lipase and cyclooxygenase-2 in a rat model of osteoarthritis.

BACKGROUND: Endocannabinoids are showing great promise as effective mediators for controlling joint inflammation and pain. One strategy that could be harnessed to promote endogenous cannabinoid function is to inhibit the enzymatic break down of endocannabinoids locally in the joint. KML29 is an inhibitor of monoacylglycerol lipase (MAGL) activity which has been shown to promote increased 2-arachodonylglycerol (2-AG) levels in the circulation and in peripheral tissues. It is also known that 2-AG can be metabolised via the cyclo-oxygenase-2 (COX-2) pathway leading to the production of pro-inflammatory prostaglandins, which may counteract the effects of 2-AG. Therefore, this study examined the effect of KML29 alone as well as in combination with low-dose celecoxib (CXB) on joint pain and inflammation in the monoiodoacetate (MIA) model of osteoarthritis (OA) pain. METHODS: Injection of MIA (3 mg) into the knee joints of male Wistar rats was used to model OA pain, inflammation, and nerve damage. Pain behaviour was assessed by von Frey hair algesiometry, and inflammation was evaluated using intravital microscopy to measure leukocyte trafficking in the synovial microvasculature. RESULTS: Intra-articular injection of MIA produced mechanical hypersensitivity as measured by von Frey hair algesiometry. Local injection of KML29 (700 µg) reduced joint pain at day 14 post-MIA induction, and this analgesic effect was blocked by the cannabinoid receptor antagonists AM281 and AM630 (P < 0.0001; n = 6). During the acute inflammatory phase of the MIA model (day 1), a significant reduction in withdrawal threshold (P < 0.0001; n = 6-8) and leukocyte trafficking was seen after treatment with KML29 + CXB (P < 0.0001; n = 6-8). Early treatment of MIA-injected knees (days 1-3) with KML29 + CXB ameliorated the development of mechanical secondary allodynia (P < 0.0001; n = 8) in the later stages of the MIA model. CONCLUSIONS: Combination therapy of KML29 plus CXB reduced joint pain and inflammation. Thus, dual inhibition of MAGL and cyclooxygenase-2 pathways could be a useful approach to alleviate joint inflammation and pain in OA joints.

Bioactive lipid metabolism in platelet "first responder" and cancer biology.

Platelets can serve as "first responders" in cancer and metastasis. This is partly due to bioactive lipid metabolism that drives both platelet and cancer biology. The two primary eicosanoid metabolites that maintain platelet rapid response homeostasis are prostacyclin made by endothelial cells that inhibits platelet function, which is counterbalanced by thromboxane produced by platelets during activation, aggregation, and platelet recruitment. Both of these arachidonic acid metabolites are inherently unstable due to their chemical structure. Tumor cells by contrast predominantly make more chemically stable prostaglandin E2, which is the primary bioactive lipid associated with inflammation and oncogenesis. Pharmacological, clinical, and epidemiologic studies demonstrate that non-steroidal anti-inflammatory drugs (NSAIDs), which target cyclooxygenases, can help prevent cancer. Much of the molecular and biological impact of these drugs is generally accepted in the field. Cyclooxygenases catalyze the rate-limiting production of substrate used by all synthase molecules, including those that produce prostaglandins along with prostacyclin and thromboxane. Additional eicosanoid metabolites include lipoxygenases, leukotrienes, and resolvins that can also influence platelets, inflammation, and carcinogenesis. Our knowledge base and technology are now progressing toward identifying newer molecular and cellular interactions that are leading to revealing additional targets. This review endeavors to summarize new developments in the field.

Mutagenicity and teratogenicity studies of vitacoxib in rats and mice.

Vitacoxib is a new drug candidate for treatment of inflammation, pain and fever as selective cyclooxygenase-2 inhibitors. In the current study, the mice sperm abnormality, mammalian erythrocyte micronucleus and in vivo chromosome aberration, and teratogenicity in SD rats were evaluated. Vitacoxib did not cause an increase in the frequency of structural chromosome aberrations, nor did it produce an increase in the number of micro nucleated polychromatic erythrocytes at dose of 1250-5000 mg/kg body weight (BW). There were no toxicological signs observed in teratogenicity test in female SD rats at dose of 200-5000 mg/kg BW. Based on these results of these studies, vitacoxib does not appear to be observed mutagenicity and teratogenicity.

Design, synthesis, biological evaluation, and nitric-oxide release studies of a novel series of celecoxib prodrugs possessing a nitric-oxide donor moiety

A new group of hybrid nitric oxide-releasing anti-inflammatory drugs (NONO-coxibs), in which an O 2-acetoxymethyl-1-(N-ethyl-N-methylamino)diazen-1-ium-1,2-diolate NO-donor moiety is attached directly to the carboxylic acid group of 1-(4-aminosulfonylphenyl)-5-aryl-1H-pyrazol-3-carboxylic acids (6a-c), were synthesized. A low amount of NO was released from the diazen-1-ium-1,2-diolate compounds 6a-c upon incubation with phosphate buffer saline (PBS) at pH 7.4 (range: pH 7.97-8.51), whereas, the percentage of NO released was significantly higher (84.5%-85.05% of the theoretical maximal release of two molecules of NO/molecule of the parent hybrid ester prodrug) when the diazen-1-ium-1,2-diolate ester prodrugs were incubated in the presence of rat serum. These incubation studies demonstrated that both NO and the anti-inflammatory 1-(4-aminosulfonylphenyl)-5-(4-H, 4-F or 4-Me-phenyl)-1H-pyrazol-3-carboxylic acid (4a-c) would be released from the parent NONO-coxib upon in vivo cleavage by non-specific serum esterases. The parent compounds 4a-c displayed good anti-inflammatory effects (ID50=81.4-112.4 mg/kg p.o.) between those exhibited by the reference drugs, aspirin (ID50=114.3 mg/kg p.o.) and celecoxib (ID50=12.6 mg/kg p.o.). Hybrid ester anti-inflammatory/NO-donor prodrugs (NONO-coxibs) offer a potential drug-design concept directed toward the development of anti-inflammatory drugs that are lacking adverse ulcerogenic and/or cardiovascular effects.

COX2 Inhibitors as Anti-Inflammatory Agents

Pain and inflammation are common problems in clinical practice. Anti-inflammatory drugs are one of the most often prescribed groups of medications. The issue is that they carry gastrointestinal (GI) and cardiovascular (CV) risks. Therefore, anti-inflammatory drugs should be used mostly in the setting of inflammation. Non inflammatory pain can be managed with other groups of drugs and therapies. For patients who do need anti-inflammatory agents, the choice is dependent on the GI and CV risk profile of the patient. Where possible, efforts should be directed to the underlying cause of the pain and inflammation.

The Coxib case: Are EP receptors really guilty?

The effects of nonsteroidal anti-inflammatory drugs (NSAIDs) originate from the inhibition of cyclooxygenase (COX), which converts arachidonic acid (AA) to prostaglandin H2 (PGH2). COX consists of two isoforms, called COX-1 and COX-2. Increasing drug selectivity for COX-2 is associated with higher CV risk. Indeed, Coxibs are shown to favour a prothrombotic state, predisposing patients to myocardial infarction (MI) or thrombotic stroke, and to counter the effects of antihypertensive drugs. Indeed, Coxibs affect kidneys, by dysregulating glomerular filtration and salt/water homeostasis. Eventually, recent data associate Coxibs to "amazing" side effects such as acute hepatitis, hyperkalemia and atrial fibrillation or flutter. The circulating concentrations reached in vivo regulate the selectivity towards one of the two COX isozymes. Thus, both tNSAIDs and Coxibs seem to be able to interfere with COX-2 activity, but the interaction depends on the concentration at which each drug may inhibit PGs synthetase in different tissues. PG synthesis inhibition leads to a multiplicity of effects which can be due to the activation of four E-type prostanoid (EP) receptors, which show differential patterns of tissue distribution. Moreover, nitric oxide (NO) bioavailability and its relation with the endogenous nitric oxide synthase (NOS) inhibitors asymmetric dimethylarginine (ADMA) and l-NG-monomethylarginine (l-NMMA), renin release by juxtaglomerular cells and aldosterone pathway, seem to determine NSAID safety also. These changes may powerfully synergize with NSAID-induced prostaglandin (PG) modifications, thus regulating vascular side effects.

Cardiovascular Effects of Nonsteroidal Anti-inflammatory Drugs.

Nonsteroidal anti-inflammatory drugs (NSAIDs) include aspirin, other traditional NSAIDs, and coxibs. Evidence obtained during the past 10 years has focused attention on the cardiovascular hazard associated with coxibs and some traditional NSAIDs. The large randomized trials of prolonged coxib treatment added importantly to information provided by epidemiological studies that had previously associated regular use of NSAIDs with increased blood pressure and enhanced risk of congestive heart failure, and identified an increased risk of myocardial infarction as a class effect of cyclooxygenase-2 inhibitors. The aim of this article is to review the cardiovascular effects of aspirin, other traditional NSAIDs, and coxibs, to discuss the mechanisms underlying these effects, and to provide a clinical perspective on the cardiovascular hazard associated with their use.

Rofecoxib-Induced Deleterious Effects Escape Detection by Organismal Performance Assays.

BACKGROUND: Organismal Performance Assays (OPAs) are a unique toxicity quantification method used to assess the safety of potentially toxic compounds, such as pharmaceuticals. OPAs utilize genetically diverse wild mice (Mus musculus) housed in semi-natural enclosures wherein exposed individuals compete directly with controls for resources. Previously, OPAs have been successful in detecting adverse effects in mice that were exposed to paroxetine. Here, we further test OPAs utility in pharmaceutical safety assessment by testing OPAs with rofecoxib, a drug with known adverse effects in humans. METHODS: We exposed mice to rofecoxib (~37.5 mg/kg/day) during gestation and into early adulthood. Exposure ceased when individuals were released into enclosures. Five independent populations were established and rofecoxib-exposed individuals (n = 58) competed directly with control individuals (n = 58) over 28 weeks. Organismal performance was determined by quantifying reproduction, survival and male competitive ability. RESULTS: In enclosures, rofecoxib-exposed males had equal reproduction, survival and competitive ability. Rofecoxib-exposed females had equal survival compared to controls but experienced 40% higher reproductive output. CONCLUSIONS: The adverse health effects of rofecoxib seen in humans escaped detection by OPAs, just as they had during traditional preclinical assays. These results may be explained by the exposure design (in enclosures, all animals were on the control diet), the relatively short duration of exposure, species differences, or because the health benefits of the drug negated the side effects. Similarly to numerous assays used in preclinical trials, OPAs cannot reveal all maladies, despite their demonstrated sensitivity in detecting cryptic toxicity from numerous exposures.