Concomitant use of gastroprotective drugs among elderly NSAID/COX-2 selective inhibitor users: a nationwide register-based study

BACKGROUND AND OBJECTIVES: NSAIDs and cyclo-oxgenase (COX)-2-selective inhibitors have been associated with gastrointestinal (GI) complications among the elderly. It is recommended that gastroprotective drugs (i.e. misoprostol, proton pump inhibitors or high doses of histamine H2 receptor antagonists) be taken concomitantly to prevent NSAID-induced GI complications among older people. However, there are concerns that the rate of concomitant use of gastroprotective drugs in elderly NSAID users is too low. This study aimed to investigate the extent to which elderly users of NSAIDs/COX-2-selective inhibitors are concurrently taking gastroprotective drugs, and to determine the factors associated with concomitant use of gastroprotective drugs and NSAIDs/COX-2-selective inhibitors in a nationwide population of older people. METHODS: We analysed data on age, sex and dispensed drugs for people>or=75 years of age registered in the Swedish Prescribed Drug Register from October to December 2005 (n=732,230) and located 41,626 NSAID/COX-2-selective inhibitor users. Logistic regression analysis was used for analysing the association between the use of different NSAIDs/COX-2-selective inhibitors and gastroprotective drugs, and between individual characteristics and use of gastroprotective drugs. RESULTS: Gastroprotective drugs were used by 22% of NSAID/COX-2-selective inhibitor users. Celecoxib, ketoprofen, meloxicam and etoricoxib were most commonly used concomitantly with gastroprotective drugs. Meloxicam and celecoxib were most strongly associated with gastroprotective drugs, after adjustment for age, sex and number of other drugs. Furthermore, NSAID/COX-2-selective inhibitor+oral corticosteroid users, NSAID/COX-2-selective inhibitor+selective serotonin reuptake inhibitor users and users of two or more NSAIDs/COX-2-selective inhibitors were more likely to concomitantly use gastroprotective drugs compared with NSAID/COX-2-selective inhibitor only users, after adjustment for age, sex and number of other drugs. However, users of NSAIDs/COX-2-selective inhibitors+anticoagulants (both warfarin and low-dose aspirin [acetylsalicylic acid]) did not show an increased likelihood of concomitant use of gastroprotective drugs, after adjustment for age, sex and number of other drugs. CONCLUSION: Our results indicate that gastroprotective drugs are not prescribed to elderly NSAID users according to guidelines. Furthermore, COX-2-selective inhibitors were used with gastroprotective drugs more often than were traditional NSAIDs. Greater awareness of factors contributing to NSAID/COX-2-selective inhibitor-induced GI complications is warranted, particularly with respect to advanced age and concurrent use of anticoagulants.     

选择性COX-2抑制剂NS-398对人胃腺癌细胞增殖和凋亡的影响

目的 研究环氧化酶2(COX-2)抑制剂NS-398对胃癌培养细胞系BGC-823增殖及凋亡的影响.方法 应用MTT法检测NS-398对胃癌细胞BGC-823细胞增殖的影响;应用流式细胞术、逆转录聚合酶链反应(RT-PCR)和Western blot法检测NS-398对胃癌细胞BGC-823细胞凋亡的影响.结果 NS-398随剂量的增加及作用时间延长对胃癌细胞呈抑制作用;体外NS-398能减少BGC-823细胞株COX-2的表达,对BGC-823有细胞毒作用,可增加细胞凋亡率.结论 NS-398可抑制胃癌BGC-823细胞的增殖,促进胃癌BGC-823细胞的凋亡.其可能机制是与抑制COX-2表达有关.     

Adrenomedullin modulates COX-2 and HGF expression in reserpine-injuried gastric mucosa in the rat

Here we show the increased hepatocyte growth factor (HGF) and cyclooxygenase-2 (COX-2) expression in gastric mucosa of rats which have developed a reserpine-induced ulcer. Such an increase of HGF and COX-2 expression was blunted in rats pretreated with adrenomedullin. Pretreatment with adrenomedullin and the adrenomedullin22-52 fragment did not result in changes of HGF and COX-2 expression, compared to the reserpine and adrenomedullin treated group. Pretreatment with adrenomedullin and the calcitonin gene-related peptide8-37 fragment (CGRP8-37) increased HGF and COX-2 expression, compared to the reserpine and adrenomedullin treated group. Our results suggest that the inhibitory effect of adrenomedullin on the expression of HGF and COX-2 is mediated by CGRP receptors.     

Effects of proton pump inhibitor on gastric mucosa hemodynamics and tissue oxygenation in anesthetized rats.

Proton pump inhibitors have been reported to have a cytoprotective action in addition to the anti-secretory action of acid. The precise mechanism, however, remains obscure. In this study, the effects of proton pump inhibitors (omeprazole and NC-1300) on gastric mucosa hemodynamics and tissue oxygenation were investigated using organ reflectance spectrophotometry in a hemorrhagic shock-reperfusion model involving anesthetized rats. Neither drug affected gastric mucosa hemodynamics nor tissue oxygenation in the basal state before hemorrhage. During the hemorrhagic shock state, however, these drugs maintained tissue oxygenation and reduced ulcer formation, although they did not show a significant effect on gastric mucosa blood volume. The results suggest that both proton pump inhibitors have an anti-ulcer action by maintaining mucosal oxygenation in addition to the anti-secretory activity of acid.     

质子泵抑制剂的胃黏膜保护作用与环氧化酶-2表达

目的　探讨质子泵抑制剂 (PPIs)的胃黏膜保护作用与环氧化酶 2 (COX 2 )表达的关系。方法　♂SD大鼠ig给予雷巴拉唑、奥美拉唑或兰索拉唑 5 0mg·kg-1·d-1,对照组ig给予质量分数为 0 5 %羧基纤维素 5ml·kg-1·d-1,连续 2wk。Westernblot和免疫组化检测胃黏膜COX 2表达。酶免疫方法测定胃黏膜中前列腺素E2 (PGE2 )水平 ,评价兰索拉唑和特异性COX 2抑制剂NS 3 98对乙醇所致大鼠胃黏膜损伤的影响。结果　 3种PPI均增加大鼠胃黏膜COX 2的表达。兰索拉唑呈剂量依赖性地增加胃黏膜中PGE2 含量 ,有效地减轻乙醇对胃黏膜的损伤作用。NS 3 98有效地阻断了兰索拉唑诱导的PGE2 合成及胃黏膜保护作用。结论　PPIs通过诱导胃黏膜COX 2表达 ,增加PGE2 合成而发挥胃黏膜保护作用     

一种选择性环氧化酶2—抑制剂JTE—522抑制RL95—2细胞的增殖及诱导其凋亡

目的:探讨环氧化酶-2抑制剂JTE-522是否对人子宫内膜癌细胞株RL95-2细胞有抑制增殖和诱导凋亡的作用及其分子机理.方法:应用体外噻唑兰法、琼脂糖凝胶电泳、酶联免疫试验、流式细胞术、RT-PCR及Western blot等方法研究JTE-522对RL952细胞增殖和凋亡的作用及其分子机理.结果:JTE522抑制RL95-2细胞的增殖、诱导其凋亡、引起G_0/G_1期阻滞和 S期抑制,并伴有COX-2 mRNA、磷酸化 Rb、CDK4蛋白表达的抑制及 p53,p21和cyclin D_1蛋白表达水平的上调.另外,细胞经 JTE-522处理后,还可见caspase-3活性的增加.结论:JTE-522抑制RL95-2细胞的增殖及诱导其凋亡,可能与COX-2mRNA,磷酸化Rb、CDK4蛋白水平的下降及 p53,p21和 cyclin D_1蛋白表达的上调有关,还可能与caspase-3的激活有关.     

Helicobacter pylori attenuates the delay in ulcer healing induced by aspirin and selective COX-2 inhibitor

Helicobacter pylori (H. pylori) and NSAIDs are recognized as major pathogenic factors in peptic ulcer disease. However, whether these two factors exert synergistic or antagonistic effects on ulcer healing has not yet been fully explained. In this study, the effects of aspirin (ASA) alone and rofecoxib, a specific prostaglandin cyclooxygenase (COX)-2 inhibitor, were compared with that of ASA and rofecoxib applied in combination with H. pylori on gastric acid secretion and healing of acetic acid ulcers in rats. The H. pylori colonization of gastric mucosa was determined by viable bacterial culture and histology. The area of ulcers was determined by planimetry, the gastric blood flow (GBF) was measured using the H₂-gas clearance method and the gastric mucosal generation of PGE₂ and plasma gastrin levels were assessed by radioimmunoassay. ASA or rofecoxib applied alone delayed significantly the healing of chronic gastric ulcers and this effect was accompanied by a marked decrease in the GBF at the ulcer margin and gastric mucosal PGE₂ generation without significant influence of gastric acid output. H. pylori that produced moderate gastric inflammation at the ulcer margin as confirmed by bacterial culture, prolonged significantly the healing of these ulcers and decreased the GBF at the ulcer margin and gastric acid output while elevating significantly the gastric mucosal PGE₂ generation and plasma gastrin levels. H. pylori attenuated significantly the ASA- and rofecoxib-induced inhibition of ulcer healing and accompanying fall in the GBF at the ulcer margin and reversed, in part, the ASA- and rofecoxib-induced alterations in PGE₂ generation. We conclude that H. pylori attenuates the delay in ulcer healing induced by ASA and rofecoxib due to enhancement in the generation of endogenous PGE₂ and gastrin release, as well as suppression of acid secretion which may limit deleterious influence of NSAID on ulcer healing.     

Sweet's syndrome associated with the intake of a selective cyclooxygenase-2 (COX-2) inhibitor

Sweet's syndrome (SS; acute febrile neutrophilic dermatosis) is a skin disorder characterized by acute tender erythematous plaques or nodules that may blister and ulcerate. The disease presents in several clinical settings including: classical (idiopathic) SS, malignancy-associated SS and drug-induced SS. Several drugs have been implicated in the etiopathogenesis of the disease with the most frequent being the granulocyte-colony stimulating factor. We report and discuss a case of SS associated with the intake of a selective cyclooxygenase-2 inhibitor, which has been rarely reported.     

Reduced incidence of upper gastrointestinal ulcer complications with the COX-2 selective inhibitor, valdecoxib

AIM: In a predefined analysis, data were pooled from eight blinded, randomized, controlled trials, and separately from three long-term, open-label trials to determine the rate of upper gastrointestinal ulcer complications with the cyclo-oxygenase-2 selective inhibitor, valdecoxib, vs. non-selective non-steroidal anti-inflammatory drugs. METHODS: In randomized, controlled trials, 7434 osteoarthritis and rheumatoid arthritis patients received placebo (n = 973), valdecoxib 5-80 mg daily (n = 4362), or a non-selective non-steroidal anti-inflammatory drug (naproxen, ibuprofen or diclofenac; n = 2099) for 12-26 weeks. In long-term, open-label trials, 2871 patients received valdecoxib 10-80 mg daily for up to 1 year. All potential events were reviewed by a blinded, independent review committee based on a priori definitions of ulcer complications (perforations, obstructions, bleeds). RESULTS: In randomized, controlled trials, 19 of 955 potential events were adjudicated to be ulcer complications. Valdecoxib was associated with a significantly lower ulcer complication rate than non-selective non-steroidal anti-inflammatory drugs (0.68% vs. 1.96%, all patients; 0.29% vs. 2.08%, non-aspirin users; P < 0.05). In long-term, open-label trials, seven of 310 potential events were adjudicated to be ulcer complications; the annualized incidence for valdecoxib was 0.39% (seven of 1791 patient-years) for all patients and 0.2% (three of 1472 patient-years) for non-aspirin users. CONCLUSIONS: Valdecoxib, including above recommended doses, is associated with a significantly lower rate of upper gastrointestinal ulcer complications than therapeutic doses of non-selective non-steroidal anti-inflammatory drugs.     

Wound collagen deposition in rats: effects of an NO-NSAID and a selective COX-2 inhibitor

Selective cyclo-oxygenase (COX)-2 inhibitors and nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NSAIDs) exhibit reduced toxicity in the gastrointestinal tract, but may affect wound healing in other tissues. In this study, we have compared the effects of a selective COX-2 inhibitor (celecoxib), a nitric-oxide releasing derivative of naproxen (HCT-3012) and naproxen in a model of wound collagen deposition in the rat. Polyvinyl alcohol sponges were implanted subcutaneously in rats. The rats were treated daily for 5 days with the test drugs at equieffective anti-inflammatory doses. Naproxen (10 mg kg(-1)) significantly decreased (45%) collagen deposition at the wound site relative to the vehicle-treated control group. In contrast, HCT-3012 (14.5 mg kg(-1)) significantly increased (62%) collagen deposition, while celecoxib (10 mg kg(-1)) had no effect. Naproxen and HCT-3012 suppressed prostaglandin (PG) E(2) levels at the wound site and whole blood thromboxane synthesis to similar degrees. Celecoxib had no significant effect on wound fluid PGE(2) levels, but slightly reduced whole blood thromboxane synthesis (by 17%). COX-1 mRNA and protein were expressed in the wound exudate, the skin surrounding the wound and in normal skin. In contrast, COX-2 mRNA, but not protein, was expressed in wound and normal skin. These results demonstrate that HCT-3012 can significantly enhance collagen deposition at a wound site, despite inhibiting prostaglandin synthesis to the same extent as the parent drug. Nitric oxide-releasing NSAIDs may represent a safer alternative to standard NSAIDs for use as anti-inflammatory and analgesic agents by post-surgery patients.     

Angiogenesis, cell proliferation and apoptosis in gastric ulcer healing. Effect of a selective cox-2 inhibitor

To elucidate the role of cyclooxygenase-2, we compared the effects of rofecoxib, a selective cyclooxygenase-2 inhibitor, and ibuprofen, a nonselective cyclooxygenase inhibitor, on the evolution of acetic-acid-induced gastric ulcers in rats, evaluating growth factor expression, the angiogenic process, cell proliferation and cell apoptosis. Levels of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF), angiogenesis and cell proliferation were analysed by immunohistochemical methods, and apoptosis was evaluated by an enzyme immunoassay. Both growth factors and microvessels appeared to be abundant in the granulation tissue of the ulcer bed. Rofecoxib (2.5 mg/kg/day) and ibuprofen (100 mg/kg/day) delayed ulcer healing, but only rofecoxib treatment provoked a reduction of bFGF expression and inhibition of the development of new microvessels. No changes in VEGF expression were detected. Results also showed that proliferation and apoptosis were increased in control ulcerated animals. Rofecoxib reduced significantly both processes. These findings demonstrate that a reduction of bFGF expression and an antiangiogenic action, as well as proliferation/apoptosis inhibition, are some of the mechanisms possibly implicated in the delay in ulcer healing seen after the administration of the highly selective COX-2 inhibitor rofecoxib.     

Biochemical and pharmacological profile of a tetrasubstituted furanone as a highly selective COX-2 inhibitor

1. DFU (5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl)phenyl-2(5H)-furanone) was identified as a novel orally active and highly selective cyclo-oxygenase-2 (COX-2) inhibitor.
2. In CHO cells stably transfected with human COX isozymes, DFU inhibited the arachidonic acid-dependent production of prostaglandin E₂ (PGE₂) with at least a 1,000 fold selectivity for COX-2 (IC₅₀=41±14 nM) over COX-1 (IC₅₀>50 μM). Indomethacin was a potent inhibitor of both COX-1 (IC₅₀=18±3 nM) and COX-2 (IC₅₀=26±6 nM) under the same assay conditions. The large increase in selectivity of DFU over indomethacin was also observed in COX-1 mediated production of thromboxane B₂ (TXB₂) by Ca²⁺ ionophore-challenged human platelets (IC₅₀>50 μM and 4.1±1.7 nM, respectively).
3. DFU caused a time-dependent inhibition of purified recombinant human COX-2 with a K_i value of 140±68 μM for the initial reversible binding to enzyme and a k₂ value of 0.11±0.06 s⁻¹ for the first order rate constant for formation of a tightly bound enzyme-inhibitor complex. Comparable values of 62±26 μM and 0.06±0.01 s⁻¹, respectively, were obtained for indomethacin. The enzyme-inhibitor complex was found to have a 1 : 1 stoichiometry and to dissociate only very slowly (t_1/2=1–3 h) with recovery of intact inhibitor and active enzyme. The time-dependent inhibition by DFU was decreased by co-incubation with arachidonic acid under non-turnover conditions, consistent with reversible competitive inhibition at the COX active site.
4. Inhibition of purified recombinant human COX-1 by DFU was very weak and observed only at low concentrations of substrate (IC₅₀=63±5 μM at 0.1 μM arachidonic acid). In contrast to COX-2, inhibition was time-independent and rapidly reversible. These data are consistent with a reversible competitive inhibition of COX-1.
5. DFU inhibited lipopolysaccharide (LPS)-induced PGE₂ production (COX-2) in a human whole blood assay with a potency (IC₅₀=0.28±0.04 μM) similar to indomethacin (IC₅₀=0.68±0.17 μM). In contrast, DFU was at least 500 times less potent (IC₅₀>97 μM) than indomethacin at inhibiting coagulation-induced TXB₂ production (COX-1) (IC₅₀=0.19±0.02 μM).
6. In a sensitive assay with U937 cell microsomes at a low arachidonic acid concentration (0.1 μM), DFU inhibited COX-1 with an IC₅₀ value of 13±2 μM as compared to 20±1 nM for indomethacin. CGP 28238, etodolac and SC-58125 were about 10 times more potent inhibitors of COX-1 than DFU. The order of potency of various inhibitors was diclofenac>indomethacin∼naproxen>nimesulide∼ meloxicam∼piroxicam>NS-398∼SC-57666>SC-58125>CGP 28238∼etodolac>L-745,337>DFU.
7. DFU inhibited dose-dependently both the carrageenan-induced rat paw oedema (ED₅₀ of 1.1 mg kg⁻¹ vs 2.0 mg kg⁻¹ for indomethacin) and hyperalgesia (ED₅₀ of 0.95 mg kg⁻¹ vs 1.5 mg kg⁻¹ for indomethacin). The compound was also effective at reversing LPS-induced pyrexia in rats (ED₅₀=0.76 mg kg⁻¹ vs 1.1 mg kg⁻¹ for indomethacin).
8. In a sensitive model in which ⁵¹Cr faecal excretion was used to assess the integrity of the gastrointestinal tract in rats, no significant effect was detected after oral administration of DFU (100 mg kg⁻¹, b.i.d.) for 5 days, whereas chromium leakage was observed with lower doses of diclofenac (3 mg kg⁻¹), meloxicam (3 mg kg⁻¹) or etodolac (10–30 mg kg⁻¹). A 5 day administration of DFU in squirrel monkeys (100 mg kg⁻¹) did not affect chromium leakage in contrast to diclofenac (1 mg kg⁻¹) or naproxen (5 mg kg⁻¹).
9. The results indicate that COX-1 inhibitory effects can be detected for all selective COX-2 inhibitors tested by use of a sensitive assay at low substrate concentration. The novel inhibitor DFU shows the lowest inhibitory potency against COX-1, a consistent high selectivity of inhibition of COX-2 over COX-1 (>300 fold) with enzyme, whole cell and whole blood assays, with no detectable loss of integrity of the gastrointestinal tract at doses >200 fold higher than efficacious doses in models of inflammation, pyresis and hyperalgesia. These results provide further evidence that prostanoids derived from COX-1 activity are not important in acute inflammatory responses and that a high therapeutic index of anti-inflammatory effect to gastropathy can be achieved with a selective COX-2 inhibitor.