Pulmonary-Allergy, Dermatological, Gastrointestinal and Arthritis: Cyclooxygenase-2: a novel target for therapeutic intervention

Analgesic and anti-inflammatory activity of the aqueous extract of Rheedia longifolia Planch & Triana

Rheedia longifolia Planch et Triana belongs to the Clusiaceae family. This plant is widely distributed in Brazil, but its chemical and pharmacological properties have not yet been studied. We report here that leaves aqueous extract of R. longifolia (LAE) shows analgesic and anti-inflammatory effects. Oral or intraperitoneal administration of this extract dose-dependently inhibited the abdominal constrictions induced by acetic acid in mice. The analgesic effect and the duration of action were similar to those observed with sodium diclofenac, a classical non-steroidal analgesic. In addition to the effect seen in the abdominal constriction model, LAE was also able to inhibit the hyperalgesia induced by lipopolysaccharide from gram-negative bacteria (LPS) in rats. We also found that R. longifolia LAE inhibited an inflammatory reaction induced by LPS in the pleural cavity of mice. Acute toxicity was evaluated in mice treated with the extract for seven days with 50 mg/kg/day. Neither death, nor alterations in weight, blood leukocyte counts or hematocrit were noted. Our results suggest that aqueous extract from R. longifolia leaves has analgesic and anti-inflammatory activity with minimal toxicity and are therefore endowed with a potential for pharmacological control of pain and inflammation.

Eficácia e tolerabilidade da nimesulida versus celecoxib na osteoartrite

O objetivo do estudo foi comparar a eficácia e a tolerabilidade da nimesulida versus o celecoxib no tratamento da osteoartrite. A casuística envolveu 57 pacientes com idade entre 40 e 80 anos, que foram randomizados em dois grupos, recebendo as medicações do estudo durante 30 dias de forma simples-cega na dosagem de um comprimido de 100mg de nimesulida duas vezes ao dia e uma cápsula de 100mg de celecoxib duas vezes ao dia. Após a inclusão no estudo na visita basal, foram realizadas três visitas com intervalo de dez dias entre elas. Os aspectos analisados foram: dor em repouso, dor em movimento e dor noturna, através de uma escala analógica da dor, duração da rigidez matinal, capacidade funcional (HAQ), classe funcional ACR-1991 e o índice de gravidade para osteoartrite de joelhos em todas as visitas. Foi também avaliado o tempo para andar 15 metros naqueles pacientes com acometimento de joelhos ou quadril. A avaliação da eficácia e tolerabilidade foi realizada pelo investigador e pelo paciente nas três visitas após o início do tratamento. Os eventos adversos foram registrados durante todo o período do estudo. Houve diminuição significativa e semelhante nas médias da escala para dor ao movimento e dor em repouso para ambos medicamentos em todas as visitas. Houve diminuição da dor noturna ao longo do tratamento no grupo celecoxib e a partir da visita 3 no grupo nimesulida, e ao final do estudo, as médias dos dois grupos foram semelhantes ( p = 0,152). As médias da duração da rigidez matinal diminuíram significativamente no grupo tratado com nimesulida durante todo o seguimento, e no grupo celecoxib a partir da visita 3, sendo semelhantes ao final do estudo ( p= 0,993). O tempo médio para andar 15 metros diminuiu significativamente no grupo nimesulida na visita 4 (p < 0,001*), e todas as médias deste intervalo de tempo foram menores do que no grupo celecoxib a partir da segunda visita. Houve diminuição significativa nas médias de capacidade funcional ( escala HAQ) no grupo nimesulida durante todo o período do estudo, enquanto que no grupo celecoxib, apenas na visita 4, onde as médias foram semelhantes ( p=0,517). No grupo nimesulida o índice de gravidade de Lequesne e Samson (1991) para osteoartrite de joelhos diminuiu significativamente a partir da visita 3, o que não ocorreu no grupo celecoxib. Os dois grupos tiveram evolução semelhante quanto à classificação funcional ACR-1991 durante o período do estudo. Ambos grupos foram semelhantes na avaliação da eficácia e da tolerabilidade segundo o paciente, e da eficácia segundo o médico. Durante o período do estudo, 21% dos pacientes do grupo nimesulida e 25% do grupo celecoxib apresentaram eventos adversos. Em conclusão, a nimesulida demonstrou eficácia e tolerabilidade semelhante ao celecoxib no tratamento da osteoartrite. A dor noturna diminuiu mais precocemente no grupo celecoxib; nos parâmetros rigidez matinal, capacidade funcional e o índice de gravidade para a osteoartrite de joelho constatou-se uma resposta mais rápida nos pacientes tratados com a nimesulida.

Study of the influence of both cyclodextrins and L-lysine on the aqueous solubility of nimesulide; isolation and characterization of nimesulide-L-lysine-cyclodextrin complexes

Nimesulide is a nonsteroidal antiinflammatory drug that exhibits a very poor water solubility (0.01 mg.mL-1). A nimesulide-beta-cyclodextrin complex prepared according to patent application WO 94/ 02177 has an aqueous solubility of approximately 16 mg.mL-1 of nimesulide. A nimesulide-L-lysine salt has also been prepared and increases the aqueous solubility of nimesulide to approximately 5.0-7.5 mg.mL-1. The purpose of the present study was to investigate the interaction of both cyclodextrins and L-lysine on the aqueous solubility of nimesulide. Nimesulide-L-lysine-beta- or gamma-cyclodextrin complexes were prepared by spray-drying. The inclusion of the nimesulide-L-lysine salt into the cyclodextrin cavity was confirmed by differential scanning calorimetry and proton nuclear magnetic resonance spectroscopy. These complexes offered remarkable aqueous solubility. The incorporation of nimesulide in a nimesulide-L-lysine-beta-cyclodextrin complex increased its water solubility by a factor of 10 at pH 1.5 (0.050 mg.mL-1 for the complex versus 0.005 mg.mL-1 for nimesulide), 160 at pH 6.8 (2.373 mg.mL-1 for the complex versus 0.015 mg.mL-1 for nimesulide), and 3600 in purified water (36.400 mg.mL-1 for the complex versus 0.01 mg.mL-1 for nimesulide).

A randomized, double-blind, crossover comparative endoscopy study on the gastroduodenal tolerability of a highly specific cyclooxygenase-2 inhibitor, flosulide, and naproxen

BACKGROUND

Inhibition of constitutively expressed cyclooxygenase (Cox-1) is thought to play an important role in the gastrointestinal toxicity of nonsteroidal anti-inflammatory drugs (NSAID), while their therapeutic action may be due to inhibition of the enzyme Cox-2, which is specifically expressed at sites of inflammation. NSAIDs with high affinity and specifity for Cox-2 hold the promise of maintaining efficacy without the gastrointestinal side effects of conventional NSAIDs.

METHODS

We assessed the gastrointestinal tolerability of flosulide (20 mg twice a day), a highly selective Cox-2 inhibitor with that of naproxen (500 mg twice a day), which has equal affinity for Cox-1 and -2 in 19 patients with osteoarthrosis in a randomized, double blind, crossover endoscopy study. Subjects were treated for 2 weeks with a 2-week washout period. Gastroduodenal damage was primarily assessed as by Lanza (grades 0-4).

RESULTS

No stomach damage was seen in 13 (68%) patients after flosulide and in 5 (37%) after naproxen (P < 0.001). Lanza scores were significantly lower after flosulide (0.58) than after naproxen (1.47) (P < 0.001; odds ratio, 84.4; 95% confidence interval, 1.45-4908). Flosulide was significantly better tolerated (P < 0.005) than naproxen.

CONCLUSION

These results endorse the idea that highly selective Cox-2 inhibitors may be associated with lesser gastrointestinal side effects than conventional NSAIDs.

Prostaglandin H-synthase-2 is the main enzyme involved in the biosynthesis of octadecanoids from linoleic acid in human dermal fibroblasts stimulated with interleukin-1beta

This study was focused on the characterization of the metabolism of linoleic acid by human dermal fibroblasts and the effect of interleukin-1 on the biosynthesis of octadecanoids. Dermal fibroblasts untreated and treated with recombinant IL-1beta were incubated with exogenous labeled linoleic acid. A combination of high performance liquid chromatography and gas chromatography-mass spectrometry was used as the analytic technique. We found that dermal fibroblasts convert linoleic acid mainly into 13-hydroxy-9-cis,11-trans-octadecadienoic acid (13-HODE) and 9-hydroxy-10-trans,12-cis-octadecadienoic acid (9-HODE), 13(S)-HODE and 9(R)-HODE being the predominant enantiomers. IL-1beta increased the formation of both 13-HODE and 9-HODE in a concentration-dependent manner with similar EC50 values as for prostanoid formation. This effect of IL-1beta on HODEs formation was concomitant with the expression of prostaglandin H-synthase-2. Formation of octadecanoids was inhibited in a concentration-dependent manner by acetylsalicylic acid and indomethacin. Dexamethasone, actinomycin D, and cycloheximide abolished the effect of IL-1beta on HODEs biosynthesis. Octadecanoid biosynthetic activity was associated with the microsomal fraction. Dermal fibroblasts incorporated [14C]-9-HODE and [14C]-13-HODE into phospholipids, mainly into phosphatidylcholine. IL-1beta increased significantly the esterification of 13-HODE in all glycerophospholipids, the major increase being observed in phosphatidylinositol. These results indicate that prostaglandin H-synthase-2 is the enzyme responsible for the increase in the ability to form HODEs of dermal fibroblasts stimulated with IL-1beta.

Inhibition of constitutive and inducible cyclooxygenase activity in human platelets and mononuclear cells by NSAIDs and Cox 2 inhibitors

A range of NSAIDs and reported Cox 2 selective compounds were tested in human freshly isolated platelets and LPS-stimulated mononuclear cells to determine their potency and selectivity as inhibitors of constitutive (presumably Cox 1) and inducible (presumably Cox 2) cyclooxygenase respectively. All compounds tested were either equipotent at inhibiting constitutive and inducible cyclooxygenase or were selective for the inducible form. The most selective compound was Dup697 and the least selective, ketoprofen. Several compounds only produced a partial inhibition of constitutive cyclooxygenase as the maximum inhibitor concentration achievable in the assay was limited to 1 mM. With the exception of paracetamol, all compounds were able to produce full inhibition curves against the inducible form. Potency estimates against constitutive Cox compare closely with published data but most compounds were consistently more potent against the inducible isoform than in published data for human cloned, microsomal Cox 2. These data suggest that human mononuclear cells are either exquisitely sensitive to some NSAIDs or they may contain another Cox isoform as yet indistinguishable from Cox 2.