Why do cyclo-oxygenase-2 inhibitors cause cardiovascular events?

Optimal Pair Matching Combined with Machine Learning Predicts a Significant Reduction in Myocardial Infarction Risk in African Americans Following Omega-3 Fatty Acid Supplementation

Conflicting clinical trial results on omega-3 highly unsaturated fatty acids (n-3 HUFA) have prompted uncertainty about their cardioprotective effects. While the VITAL trial found no overall cardiovascular benefit from n-3 HUFA supplementation, its substantial African American (AfAm) enrollment provided a unique opportunity to explore racial differences in response to n-3 HUFA supplementation. The current observational study aimed to simulate randomized clinical trial (RCT) conditions by matching 3766 AfAm and 15,553 non-Hispanic White (NHW) individuals from the VITAL trial utilizing propensity score matching to address the limitations related to differences in confounding variables between the two groups. Within matched groups (3766 AfAm and 3766 NHW), n-3 HUFA supplementation's impact on myocardial infarction (MI), stroke, and cardiovascular disease (CVD) mortality was assessed. A weighted decision tree analysis revealed belonging to the n-3 supplementation group as the most significant predictor of MI among AfAm but not NHW. Further logistic regression using the LASSO method and bootstrap estimation of standard errors indicated n-3 supplementation significantly lowered MI risk in AfAm (OR 0.17, 95% CI [0.048, 0.60]), with no such effect in NHW. This study underscores the critical need for future RCT to explore racial disparities in MI risk associated with n-3 HUFA supplementation and highlights potential causal differences between supplementation health outcomes in AfAm versus NHW populations.

Interpreting Clinical Trials With Omega-3 Supplements in the Context of Ancestry and FADS Genetic Variation

Human diets in developed countries such as the US have changed dramatically over the past 75 years, leading to increased obesity, inflammation, and cardiometabolic dysfunction. Evidence over the past decade indicates that the interaction of genetic variation with changes in the intake of 18-carbon essential dietary omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFA), linoleic acid (LA) and α-linolenic acid (ALA), respectively, has impacted numerous molecular and clinical phenotypes. Interactions are particularly relevant with the FADS1 and FADS2 genes, which encode key fatty acid desaturases in the pathway that converts LA and ALA to their long chain (≥20 carbons), highly unsaturated fatty acid (HUFA) counterparts. These gene by nutrient interactions affect the levels and balance of n-6 and n-3 HUFA that in turn are converted to a wide array of lipids with signaling roles, including eicosanoids, docosanoids, other oxylipins and endocannabinoids. With few exceptions, n-6 HUFA are precursors of pro-inflammatory/pro-thrombotic signaling lipids, and n-3 HUFA are generally anti-inflammatory/anti-thrombotic. We and others have demonstrated that African ancestry populations have much higher frequencies (vs. European-, Asian- or indigenous Americas-ancestry populations) of a FADS "derived" haplotype that is associated with the efficient conversion of high levels of dietary n-6 PUFA to pro-inflammatory n-6 HUFA. By contrast, an "ancestral" haplotype, carrying alleles associated with a limited capacity to synthesize HUFA, which can lead to n-3 HUFA deficiency, is found at high frequency in certain Hispanic populations and is nearly fixed in several indigenous populations from the Americas. Based on these observations, a focused secondary subgroup analysis of the VITAL n-3 HUFA supplementation trial stratifying the data based on self-reported ancestry revealed that African Americans may benefit from n-3 HUFA supplementation, and both ancestry and FADS variability should be factored into future clinical trials design.

Ion Transport Modulators Differentially Modulate Inflammatory Responses in THP-1-Derived Macrophages

Ion transport modulators are most commonly used to treat various noncommunicable diseases including diabetes and hypertension. They are also known to bind to receptors on various immune cells, but the immunomodulatory properties of most ion transport modulators have not been fully elucidated. We assessed the effects of thirteen FDA-approved ion transport modulators, namely, ambroxol HCl, amiloride HCl, diazoxide, digoxin, furosemide, hydrochlorothiazide, metformin, omeprazole, pantoprazole, phenytoin, verapamil, drug X, and drug Y on superoxide production, nitric oxide production, and cytokine expression by THP-1-derived macrophages that had been stimulated with ethanol-inactivated Mycobacterium bovis BCG. Ambroxol HCl, diazoxide, digoxin, furosemide, hydrochlorothiazide, metformin, pantoprazole, phenytoin, verapamil, and drug Y had an inhibitory effect on nitric oxide production, while all the test drugs had an inhibitory effect on superoxide production. Amiloride HCl, diazoxide, digoxin, furosemide, phenytoin, verapamil, drug X, and drug Y enhanced the expression of IL-1β and TNF-α. Unlike most immunomodulatory compounds currently in clinical use, most of the test drugs inhibited some inflammatory processes while promoting others. Ion pumps and ion channels could therefore serve as targets for more selective immunomodulatory agents which do not cause overt immunosuppression.

Polyunsaturated fatty acid biosynthesis pathway and genetics. implications for interindividual variability in prothrombotic, inflammatory conditions such as COVID-19✰,✰✰,★,★★

COVID-19 symptoms vary from silence to rapid death, the latter mediated by both a cytokine storm and a thrombotic storm. SARS-CoV (2003) induces Cox-2, catalyzing the synthesis, from highly unsaturated fatty acids (HUFA), of eicosanoids and docosanoids that mediate both inflammation and thrombosis. HUFA balance between arachidonic acid (AA) and other HUFA is a likely determinant of net signaling to induce a healthy or runaway physiological response. AA levels are determined by a non-protein coding regulatory polymorphisms that mostly affect the expression of FADS1, located in the FADS gene cluster on chromosome 11. Major and minor haplotypes in Europeans, and a specific functional insertion-deletion (Indel), rs66698963, consistently show major differences in circulating AA (>50%) and in the balance between AA and other HUFA (47-84%) in free living humans; the indel is evolutionarily selective, probably based on diet. The pattern of fatty acid responses is fully consistent with specific genetic modulation of desaturation at the FADS1-mediated 20:3→20:4 step. Well established principles of net tissue HUFA levels indicate that the high linoleic acid and low alpha-linoleic acid in populations drive the net balance of HUFA for any individual. We predict that fast desaturators (insertion allele at rs66698963; major haplotype in Europeans) are predisposed to higher risk and pathological responses to SARS-CoV-2 could be reduced with high dose omega-3 HUFA.

Raging the War Against Inflammation With Natural Products

Over the last few decade Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are the drugs of choice for treating numerous inflammatory diseases including rheumatoid arthritis. The NSAIDs produces anti-inflammatory activity via inhibiting cyclooxygenase enzyme, responsible for the conversation of arachidonic acid to prostaglandins. Likewise, cyclooxegenase-2 inhibitors (COX-2) selectively inhibit the COX-2 enzyme and produces significant anti-inflammatory, analgesic, and anti-pyretic activity without producing COX-1 associated gastrointestinal and renal side effects. In last two decades numerous selective COX-2 inhibitors (COXIBs) have been developed and approved for various inflammatory conditions. However, data from clinical trials have suggested that the prolong use of COX-2 inhibitors are also associated with life threatening cardiovascular side effects including ischemic heart failure and myocardial infection. In these scenario secondary metabolites from natural product offers a great hope for the development of novel anti-inflammatory compounds. Although majority of the natural product based compounds exhibit more selectively toward COX-1. However, the data suggest that slight structural modification can be helpful in developing COX-2 selective secondary metabolites with comparative efficacy and limited side effects. This review is an effort to highlight the secondary metabolites from terrestrial and marine source with significant COX-2 and COX-2 mediated PGE2 inhibitory activity, since it is anticipated that isolates with ability to inhibit COX-2 mediated PGE2 production would be useful in suppressing the inflammation and its classical sign and symptoms. Moreover, this review has highlighted the potential lead compounds including berberine, kaurenoic acid, α-cyperone, curcumin, and zedoarondiol for further development with the help of structure-activity relationship (SAR) studies and their current status.

Alleviating Promotion of Inflammation and Cancer Induced by Nonsteroidal Anti-Inflammatory Drugs

Clinical Relevance

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) including aspirin are of intensive use nowadays. These drugs exert their activity via the metabolism of arachidonic acid (AA) by cyclooxygenase inhibition. Though beneficial for health in some instances, both unspecific and specific cyclooxygenase inhibitor activity interfere with AA metabolism producing also proinflammatory lipids that may promote cancer.

Materials and Methods

This review is based on available literature on clinical uses, biochemical investigations, molecular medicine, pharmacology, toxicity, and epidemiology-clinical studies on NSAIDs and other drugs that may be used accordingly, which was collected from electronic (SciFinder, Medline, Science Direct, and ACS among others) and library searches of books and journals.

Results

Relevant literature supports the notion that NDSAID use may also promote proinflammatory biochemical events that are also related to precancerous predisposition. Several agents are proposed that may be employed in immediate future to supplement and optimize treatment with NSAIDs. In this way serious side effects arising from promotion of inflammation and cancer, especially in chronic NSAID users and high risk groups of patients, could be avoided.

Celecoxib and 2,5-dimethylcelecoxib inhibit intestinal cancer growth by suppressing the Wnt/β-catenin signaling pathway

We previously reported that celecoxib, a selective COX-2 inhibitor, strongly inhibited human colon cancer cell proliferation by suppressing the Wnt/β-catenin signaling pathway. 2,5-Dimethylcelecoxib (DM-celecoxib), a celecoxib analog that does not inhibit COX-2, has also been reported to have an antitumor effect. In the present study, we elucidated whether DM-celecoxib inhibits intestinal cancer growth, and its underlying mechanism of action. First, we compared the effect of DM-celecoxib with that of celecoxib on the human colon cancer cell lines HCT-116 and DLD-1. 2,5-Dimethylcelecoxib suppressed cell proliferation and inhibited T-cell factor 7-like 2 expression with almost the same strength as celecoxib. 2,5-Dimethylcelecoxib also inhibited the T-cell factor-dependent transcription activity and suppressed the expression of Wnt/β-catenin target gene products cyclin D1 and survivin. Subsequently, we compared the in vivo effects of celecoxib and DM-celecoxib using the Mutyh-/- mouse model, in which oxidative stress induces multiple intestinal carcinomas. Serum concentrations of orally administered celecoxib and DM-celecoxib elevated to the levels enough to suppress cancer cell proliferation. Repeated treatment with celecoxib and DM-celecoxib markedly reduced the number and size of the carcinomas without showing toxicity. These results suggest that the central mechanism for the anticancer effect of celecoxib derivatives is the suppression of the Wnt/β-catenin signaling pathway but not the inhibition of COX-2, and that DM-celecoxib might be a better lead compound candidate than celecoxib for the development of novel anticancer drugs.

Pain Management After Outpatient Anterior Cruciate Ligament Reconstruction: A Systematic Review of Randomized Controlled Trials

BACKGROUND

Effective pain management after anterior cruciate ligament (ACL) reconstruction improves patient satisfaction and function.

PURPOSE

To collect and evaluate the available evidence from randomized controlled trials (RCTs) on pain control after ACL reconstruction.

STUDY DESIGN

Systematic review.

METHODS

A systematic literature review was performed using PubMed, Medline, Google Scholar, UpToDate, Cochrane Reviews, CINAHL, and Scopus following PRISMA guidelines (July 2014). Only RCTs comparing a method of postoperative pain control to another method or placebo were included.

RESULTS

A total of 77 RCTs met inclusion criteria: 14 on regional nerve blocks, 21 on intra-articular injections, 4 on intramuscular/intravenous injections, 12 on multimodal regimens, 6 on oral medications, 10 on cryotherapy/compression, 6 on mobilization, and 5 on intraoperative techniques. Single-injection femoral nerve blocks provided superior analgesia to placebo for up to 24 hours postoperatively; however, this also resulted in a quadriceps motor deficit. Indwelling femoral catheters utilized for 2 days postoperatively provided superior analgesia to a single-injection femoral nerve block. Local anesthetic injections at the surgical wound site or intra-articularly provided equivalent analgesia to regional nerve blocks. Continuous-infusion catheters of a local anesthetic provided adequate pain relief but have been shown to cause chondrolysis. Cryotherapy improved analgesia compared to no cryotherapy in 4 trials, while in 4 trials, ice water and water at room temperature provided equivalent analgesic effects. Early weightbearing decreased pain compared to delayed weightbearing. Oral gabapentin given preoperatively and oral zolpidem given for the first week postoperatively each decreased opioid consumption as compared to placebo. Ibuprofen reduced pain compared to acetaminophen. Oral ketorolac reduced pain compared to hydrocodone-acetaminophen.

CONCLUSION

Regional nerve blocks and intra-articular injections are both effective forms of analgesia. Cryotherapy-compression appears to be beneficial, provided that intra-articular temperatures are sufficiently decreased. Early mobilization reduces pain symptoms. Gabapentin, zolpidem, ketorolac, and ibuprofen decrease opioid consumption. Despite the vast amount of high-quality evidence on this topic, further research is needed to determine the optimal multimodal approach that can maximize recovery while minimizing pain and opioid consumption.

CLINICAL RELEVANCE

These results provide the best available evidence from RCTs on pain control regimens after ACL reconstruction.

Diclofenac induces proteasome and mitochondrial dysfunction in murine cardiomyocytes and hearts

BACKGROUND

One of the most common nonsteroidal anti-inflammatory drugs (NSAIDs) used worldwide, diclofenac (DIC), has been linked to increased risk of cardiovascular disease (CVD). The molecular mechanism(s) by which DIC causes CVD is unknown.

METHODS

Proteasome activities were studied in hearts, livers, and kidneys from male Swiss Webster mice treated with either 100mg/kg DIC for 18h (acute treatment) or 10mg/kg DIC for 28days (chronic treatment). Cultured H9c2 cells and neonatal cardiomyocytes were also treated with different concentrations of DIC and proteasome function, cell death and ROS generation studied. Isolated mouse heart mitochondria were utilized to determine the effect of DIC on various electron transport chain complex activities.

RESULTS

DIC significantly inhibited the chymotrypsin-like proteasome activity in rat cardiac H9c2 cells, murine neonatal cardiomyocytes, and mouse hearts, but did not affect proteasome subunit expression levels. Proteasome activity was also affected in liver and kidney tissues from DIC treated animals. The levels of polyubiquitinated proteins increased in hearts from DIC treated mice. Importantly, the levels of oxidized proteins increased while the β5i immunoproteasome activity decreased in hearts from DIC treated mice. DIC increased ROS production and cell death in H9c2 cells and neonatal cardiomyocytes while the cardioprotective NSAID, aspirin, had no effect on ROS levels or cell viability. DIC inhibited mitochondrial Complex III, a major source of ROS, and impaired mitochondrial membrane potential suggesting that mitochondria are the major sites of ROS generation.

CONCLUSION

These results suggest that DIC induces cardiotoxicity by a ROS dependent mechanism involving mitochondrial and proteasome dysfunction.

Panax notoginseng saponin is superior to aspirin in inhibiting platelet adhesion to injured endothelial cells through COX pathway in vitro

OBJECTIVE

This study was designed to investigate the effect of Panax notoginseng saponin (PNS) on platelet adhesion to injured endothelial cells (ECs) and platelet activation induced by injured ECs, and to explore its underlying mechanisms.

METHODS

Human umbilical vein endothelial cells (HUVECs) pretreated with aspirin (ASA,15μg/mL) or PNS (160μg/mL), or neither, were exposed to oxidized low-density lipoprotein (ox-LDL,80mg/L) for 16h. Platelets were then added and co-cultured with HUVECs for 5min. Platelet adhesion to ECs, platelet CD62p expression, and HUVEC apoptosis were assessed by fluorescence activated cell sorting (FACS)·Supernatant concentration of 6-keto-PGF1α and thromboxane 2 (TXB2) were measured by radioimmunoassay. Cyclooxygenase-1 (COX-1) and COX-2 protein expression were measured by western blotting.

RESULTS

The inhibitory effect of PNS on platelet activation was similar to ASA, but the inhibitory effect of PNS on platelet adhesion to ECs was superior to ASA. PNS modulated COX-2 expression, and increased 6-keto-PGF1α concentration in HUVECs, while down-regulated COX-1 expression and decreased supernatant TXB2 concentration in platelets. Co-culturing of injured HUVECs with platelets increased HUVEC apoptosis induced by ox-LDL compared with HUVECs cultured without platelets; ASA increased HUVEC apoptosis induced by ox-LDL when cultured without platelets, while decreased the apoptosis when co-cultured with platelets.

CONCLUSIONS

EC protection by ASA is closely associated with its inhibitory effect on platelet activation. PNS is superior to ASA in protecting ECs and in inhibiting platelet adhesion to injured ECs, and the regulation of COX pathway in both ECs and platelets might be the underlying mechanisms of PNS.

The Role of Oxygen Sensors, Hydroxylases, and HIF in Cardiac Function and Disease

Ischemic heart disease is the leading cause of death worldwide. Oxygen-sensing proteins are critical components of the physiological response to hypoxia and reperfusion injury, but the role of oxygen and oxygen-mediated effects is complex in that they can be cardioprotective or deleterious to the cardiac tissue. Over 200 oxygen-sensing proteins mediate the effects of oxygen tension and use oxygen as a substrate for posttranslational modification of other proteins. Hydroxylases are an essential component of these oxygen-sensing proteins. While a major role of hydroxylases is regulating the transcription factor HIF, we investigate the increasing scope of hydroxylase substrates. This review discusses the importance of oxygen-mediated effects in the heart as well as how the field of oxygen-sensing proteins is expanding, providing a more complete picture into how these enzymes play a multifaceted role in cardiac function and disease. We also review how oxygen-sensing proteins and hydroxylase function could prove to be invaluable in drug design and therapeutic targets for heart disease.

Inflammation revisited: inflammation versus resolution of inflammation following myocardial infarction

Myocardial infarction (MI) is the main cause for the progression of the left ventricle towards congestive heart failure. The optimal healing after MI requires timely induction and resolution of inflammation. Primarily, there have been a number of strategies applied to inhibit the post-MI inflammation but approaches that focus on the resolution of inflammation have sparsely been used in the treatment of heart failure. The early attempts to inhibit post-MI inflammation resulted in adverse outcomes that were realized in heart failure trials. We provide here an overview on the cyclooxygenase (COX)- and lipoxygenase (LOX)-derived lipid mediators that are either impairing or resolving the post-MI inflammation. With the evolution of lipidomics there has been emerging novel bioactive-specialized lipid mediators that promise to resolve chronic inflammation rather than promoting inhibition. The current review is focused on post-MI immune cells kinetics and the unexplored array of lipid mediators that are coordinated by COX and LOX. Thus, an emphasis on COX and LOX poses key questions and potential for the development of novel targets in the heart failure treatment strategy. This updated dynamic approach aims to fuse basic pre-clinical discoveries and translational bioactive lipid-based resolvin discoveries that could be potentially used in the clinic for the treatment of heart failure.

Acute Kidney Injury Secondary to NSAID Diagnosed on 99mTc MDP Bone Scan

A bone scan with 99mTc MDP was obtained to rule out the presence of micro fractures in a patient with the diagnosis of idiopathic osteoporosis. There was not any sign of micro fractures, but interestingly, both kidneys were diffusely very active. A differential diagnosis of acute kidney injury secondary to the use of nonsteroidal anti-inflammatory drug was made and reported after elimination of other clinical situations. The renal functions obtained following bone scan were impaired. The anti-inflammatory drug was discontinued. The renal functions were recovered starting with the following day.

Conflict of interest:None declared.

Synthesis and biological evaluation of some N-arylpyrazoles and pyrazolo[3,4-d]pyridazines as anti-inflammatory agents

A series of 3,4-bis-chalcone-N-arylpyrazoles 3a-k was prepared from diacetyl pyrazoles 2a-e. The reaction of 2d and 2e with hydrazine hydrate gave pyrazolo[3,4-d]pyridazine derivatives 4a-b. Furthermore, the reaction of 2a-e with thiosemicarbazide afforded pyrazolo[3,4-d]pyridazine thiocyanate salts 5a-e. The synthesized compounds were subjected to in vivo anti-inflammatory and ulcerogenic activity measurements, in addition to determination of their in vitro COX selectivity, to give a full profile about their anti-inflammatory activities. Compounds 3c, 3f, 3i, and 3e showed significant anti-inflammatory activity among the synthesized compounds. Moreover, docking studies were performed to give an explanation for their anti-inflammatory activity through COX selectivity.

Virtual Screening for Finding Novel COX-2 Inhibitors as Antitumor Agents

The cyclooxygenase-2 (COX-2) enzyme binds to arachidonic acid resulting in the release of metabolites that induce pain and inflammatory responses. Recent studies have shown that strong COX-2 expression is highly correlated with increased tumor risk. Therefore, the development of potent COX-2 inhibitors to relieve pain and treat cancers requires further investigation. We used virtual screening to find three COX-2 inhibitors (Phar-95239, T0511-4424 and Zu- 4280011) from a huge zinc database containing 2000000 compounds. The effects of the compounds on COX-2 were compared to those on COX-1 using a colorimetric COX (ovine) screening assay kit. The selectivity index, the ratio of IC₅₀ for COX-1 inhibition to that of COX-2, calculated were MTT assay was used to evaluate the cytotoxic activity of the compounds using different dilutions. The IC₅₀ values were calculated. Based on the results of the MTT assay, the IC₅₀ values for compounds Phar-95239, T0511-4424 and Zu-4280011 were 178.52, 143 and 97.61 µM, respectively, and the selectivity indices of the compounds were 11.36, 12.20 and 20.03, respectively. These results indicated a relationship between the selectivity index and anticancer activity. Zu-4280011 displayed the highest selectivity index and the best results in the MTT assay among selected componds.

Colon-specific delivery of celecoxib is a potential strategy to improve toxicological and pharmacological properties of the selective Cox-2 inhibitor: implication in treatment of familiar adenomatous polyposis

In general, colon-specific delivery of a drug decreases systemic absorption and increases therapeutic concentration of the drug at the target site. N-succinylglutam-1 or 5-yl celecoxib (SG1C and SG5C) were prepared as a colon-specific prodrug of celecoxib, a selective Cox-2 inhibitor, and investigated whether the celecoxib derivatives could deliver celecoxib to the target site and improve cardiovascular toxicity and therapeutic effectiveness for the treatment of familiar adenomatous polyposis. SG1C and SA5C were cleaved to release celecoxib in the cecal contents while stable in small intestinal contents. The cecal release of celecoxib was much greater for SG1C than SG5C. SG1C administered orally was barely detected in the blood and urine. SG1C delivered much greater amount of celecoxib to the large intestine while keeping the plasma concentration of celecoxib at much lower level compared with oral administration of free celecoxib. Consistent with these pharmacokinetic results, SG1C supplied a greater concentration of celecoxib for the entire colonic tissue and did not change the serum level of 6-keto-PGF(1α) whose decrease is associated with the cardiovascular toxicity of celecoxib. Taken together, colon-specific delivery of celecoxib using a prodrug approach may be a useful strategy to improve toxicological and pharmacological properties of celecoxib.

Blockade of interleukin-17A protects against coxsackievirus B3-induced myocarditis by increasing COX-2/PGE2 production in the heart

The Th17/interleukin (IL)-17 axis controls inflammation and might be important in the pathogenesis of experimental autoimmune myocarditis (EAM) and other autoimmune diseases. However, the mechanism underlying the increased Th17 cell response in coxsackievirus-induced myocarditis remains unclear. This study aimed to elucidate the regulatory mechanisms affected by blocking IL-17A responses in acute virus-induced myocarditis (AVMC) mice. The results showed that IL-17A and COX-2 proteins were significantly increased in the cardiac tissue of acute myocarditis, as were Th17 cells in the spleen. Using anti-mouse IL-17Ab to block IL-17A on day 7 of the viral myocarditis led to decreased expressions of cardiac tumor-necrosis factor alpha, IL-17A and transforming growth factor beta in AVMC mice compared to isotype control mice. COX-2 and prostaglandin E2 proteins were dramatically elevated, followed by marked reductions in CVB3 replication and myocardial injury. These results hint that the Th17/IL-17 axis is intimately associated with viral replication in acute myocarditis via induction of COX-2 and prostaglandin E2.

Myocardial Infarction and Its Association with the Use of Nonselective NSAIDs: A Nested Case-Control and Time-to-Event Analysis

OBJECTIVE

In April 2005, the US Food and Drug Administration issued a public health advisory warning to health care clinicians about the cardiovascular (CV) safety of nonsteroidal anti-inflammatory drugs (NSAIDs). Although the warning about cyclooxygenase-2 selective NSAIDs was anticipated, little data exists about the CV safety of nonselective NSAIDs. We analyzed data from a group of NSAID users to determine if specific nonselective agents were associated with an increased risk of myocardial infarctions (MIs) and sudden cardiac death (SCD).

DESIGN

A nested case-control design was used to study NSAID users ages 18 to 84 years. Cases were defined by a hospital admission for MI or an out-of-hospital SCD. Study control subjects were matched for age, sex, current Kaiser Permanente membership, and geographic location (Northern or Southern California). Odds ratios (OR) were estimated using conditional logistic regression.

RESULTS

Our base population included 1,394,764 NSAID users. From this population we identified 8143 cases and 31,496 matched study control subjects. The median time to event was <100 days for all NSAIDs. Two nonselective NSAIDs were associated with increased odds of adverse CV outcomes: indomethacin (OR, 1.27; 95% confidence interval, 1.04-1.56) and naproxen (OR, 1.14; 95% confidence interval, 1.00-1.30).

CONCLUSION

Our results suggest that some nonselective NSAIDs are associated with an increased risk of MI and SCD. We found the increased risk to be small compared with the risk associated with rofecoxib. Cardiovascular events occurred early in therapy. Caution is warranted with some nonselective NSAIDs, especially those for which other studies have found evidence of risk.

Synthesis of Diarylpyrazoles Containing a Phenylsulphone or Carbonitrile Moiety and their Chalcones as Possible Anti-Inflammatory Agents

A series of chalcone-based diarylpyrazoles containing a phenylsulphone or carbonitrile moiety was synthesized. Thus, 3-acetylpyrazoles 6a-c and 10a-c were used as useful substrates in facile synthesis of functional pyrazoles 7a-f and 11a-f, respectively. The anti-inflammatory activity and ulcerogenic effect were evaluated and some of the obtained products possessed a significant anti-inflammatory activity. 1-[1-(3-Methylphenyl)-5-phenyl-4-(phenylsulfonyl)-1H-pyrazol-3-yl]ethanone (6b) showed a high activity when compared with indomethacin as reference drug with lower gastrointestinal (GI) profile. Furthermore, molecular docking studies were performed in order to rationalize the obtained biological results.

Synthesis of 2-(N-Benzylpyrrolyl)-benzimidazoles Using Polyphosphoric Acid Prompted Cyclocondensation

Synthesis of a series of 2-substituted benzimidazoles was carried out for screening anti-inflammatory activities. 2-(N-benzylpyrrolyl)-benzimidazoles 9a-k were synthesized from N-benzyl-2-pyrrole carboxylic acids 8a-d and 4-substituted-1,2-phenylenediamines by cyclocondensation utilizing polyphosphoric acid (PPA) as condensing agent. The N-benzyl-2-pyrrole carboxylic acids were prepared by standard method of N-benzylation of 2-pyrrole carboxylate using NaH/DMF and appropriately substituted benzyl halides followed by alkaline hydrolysis.

Treatment of chronic non-malignant pain in the elderly: safety considerations

Non-malignant pain in the elderly is frequently under-treated, with physicians appearing to be uncertain concerning how best to achieve optimum management of this common problem in individual cases. The aim of this review is to provide a brief overview and discuss the variety of interacting factors that contribute to the continuing under-treatment of chronic non-malignant pain in the older population. The central objective is to encourage safer and more effective pain management in a population that is highly vulnerable to painful conditions and to the consequences of poorly treated pain. Under-treatment of pain as experienced by the elderly is largely a consequence of uncertainties that arise within a complex environment that is underscored and exacerbated by the progressive and rapid aging of the global population. Uncertainties include the optimum management of pain in geriatric syndromes, frailty and dementia, and their impact on diagnosis, pain assessment and choices of treatment modalities. There is an inadequate evidence base for pharmacological interventions in older persons with respect to pharmacokinetic and pharmacodynamic changes that occur with aging. In this review, the prevalence of chronic pain and the incidence of adverse drug reactions are identified as factors that encourage conservatism in prescribing, as are major predictors of adverse drug reactions, i.e. aging, inappropriate combinations of medications and polypharmacy. The major classes of analgesic drugs are summarized with reference to their mechanisms of action, analgesic properties and known adverse effects. Although all medications have associated risks, the use of analgesics in managing persistent pain in elderly people is widely supported and guided on the basis of clinical experience and consensus among specialists in geriatrics and pain management. It is concluded that the absence of trial data, specific to the elderly, is substantially offset by information based on clinical experience and expert consensus statements. Used appropriately, analgesic and adjuvant treatments can and should be employed to relieve persistent pain in the expanding elderly population.

Multi-Target Approaches in Colon Cancer Chemoprevention Based on Systems Biology of Tumor Cell-Signaling

Colorectal cancer is the leading cause of cancer related deaths in the United States. Although it is preventable, thousands of lives are lost each year in the U.S. to colorectal cancer than to breast cancer and AIDS combined. In colon cancer, the formation and progression of precancerous lesions like aberrant crypt foci and polyps is associated with the up-regulation of cycloxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and hydroxy methyl glutaryl CoA reductase (HMG-CoA reductase). The current review will focus on the signaling pathway involving COX-2 and HMG-CoA reductase enzymes and their downstream effectors in signaling mechanism. Cancer cells need huge pools of both cholesterol and isoprenoids to sustain their unlimited growth potential. Cholesterol by modulating caveolae formation regulates several signaling molecules like AKT, IGFR, EGFR and Rho which are involved in cell growth and survival. Cholesterol is also essential for lipid body formation which serves as storage sites for COX-2, eicosanoids and caveolin-1. Experimental studies have identified important mechanisms showing that COX-2, caveolin-1, lipid bodies and prenylated proteins is involved in carcinogenesis. Therefore multi-target, multi-drug approach is the ideal choice for effective colon cancer chemoprevention. This review will give an overview of the two pathways, their signaling networks, and the interactions between the components of the two networks in the activation and regulation of cell signaling involving growth/survival and explain the rationale for colon cancer chemoprevention using COX-2 inhibitors and statins.

Expression of cyclooxygenase-1 and cyclooxygenase-2 in the normal human heart and in myocardial infarction

INTRODUCTION

Cyclooxygenase is a key enzyme in prostanoid synthesis. It exists in two isoforms: cyclooxygenase-1 (COX-1), which is constitutively expressed in cells and tissues maintaining normal homeostasis, and cyclooxygenase-2 (COX-2), which is normally not present in most cells, but can be induced by various stimuli. Little is known about the significance of COX isoforms in the normal human heart and in myocardial infarction (MI). Thus, we aimed to investigate the immunohistochemical expression of COX-1 and COX-2 in the normal human heart and in MI.

METHODS

Our study included autopsy samples of heart tissue from 15 healthy individuals who died in accidents, and from 40 patients with MI who died few hours to a month after the onset of symptoms. Immunohistochemistry was performed by a sensitive peroxidase-streptavidin method on formalin fixed, paraffin-embedded tissue, using monoclonal antibodies against COX-1 and COX-2.

RESULTS

In normal hearts, COX-1 was found in endothelial and smooth muscle cells of blood vessels and in endothelial cells of the endocardium. In MI, it was expressed in inflammatory cells, as well as in myofibroblasts and capillaries of granulation and fibrous tissue. COX-2 was either not present or it was present in occasional myocytes in the normal hearts. In MI, its expression was induced in cardiomyocytes as well as in interstitial inflammatory cells, and in capillaries and myofibroblasts in granulation tissue.

CONCLUSIONS

Our results suggest that COX-1 is associated with normal homeostasis in the heart, whereas COX-2 probably mediates inflammatory reaction in MI. It appears that both COX-1 and COX-2 are associated with the healing processes and scar formation after MI.

CJ-023,423, a novel, potent and selective prostaglandin EP4 receptor antagonist with antihyperalgesic properties

The prostaglandin (PG) EP(4) receptor subtype is expressed by peripheral sensory neurons. Although a potential role of EP(4) receptor in pain has been suggested, a limited number of selective ligands have made it difficult to explore the physiological functions of EP(4) or its potential as a new analgesic target. Here, we describe the in vitro and in vivo pharmacology of a novel EP(4) receptor antagonist, N-[({2-[4-(2-ethyl-4,6-dimethyl-1H-imidazo [4,5-c] pyridin-1-yl) phenyl]ethyl}amino) carbonyl]-4-methylbenzenesulfonamide (CJ-023,423). In vitro, CJ-023,423 inhibits [(3)H]PGE(2) binding to both human and rat EP(4) receptors with K(i) of 13 +/- 4 and 20 +/- 1 nM, respectively. CJ-023,423 is highly selective for the human EP(4) receptor over other human prostanoid receptor subtypes. It also inhibits PGE(2)-evoked elevation in intracellular cAMP at the human and rat EP(4) receptors with pA(2) of 8.3 +/- 0.03 and 8.2 +/- 0.2 nM, respectively. In vivo, oral administration of CJ-023,423 significantly reduces thermal hyperalgesia induced by intraplantar injection of PGE(2) (ED(50) = 12.8 mg/kg). CJ-023,423 is also effective in models of acute and chronic inflammatory pain. CJ-023,423 significantly reduces mechanical hyperalgesia in the carrageenan model. Furthermore, CJ-023,423 significantly reverses complete Freund's adjuvant-induced chronic inflammatory pain response. Taken together, the present data indicate that CJ-023,423, a highly potent and selective antagonist of both human and rat EP(4) receptors, produces antihyperalgesic effects in animal models of inflammatory pain. Thus, specific blockade of the EP(4) receptor signaling may represent a novel therapeutic approach for the treatment of inflammatory pain.

Chemical-induced atrial thrombosis in NTP rodent studies

Cardiac thrombosis, one of the causes of sudden death throughout the world, plays a principal role in several cardiovascular diseases, such as myocardial infarction and stroke in humans. Data from studies of induction of chemical thrombosis in rodents help to identify substances in our environment that may contribute to cardiac thrombosis. Results for more than 500 chemicals tested in rodents in 2-year bioassays have been published as Technical Reports of the National Toxicology Program (NTP) http://ntp-server.niehs.nih.gov/index. We evaluated atrial thrombosis induced by these chemical exposures and compared it to similarly induced lesions reported in the literature. Spontaneous rates of cardiac thrombosis were determined for control Fischer 344 rats and B6C3F1 mice: 0% in rats and mice in 90-day studies and, in 2-year studies, 0.7% in both genders of mice, 4% in male rats, and 1% in female rats. Incidences of atrial thrombosis were increased in high-dosed groups involving 13 compounds (incidence rate: 20-100%): 2-butoxyethanol, C.I. Direct Blue 15, bis(2-chloroethoxy)methane, diazoaminobenzene, diethanolamine, 3,3'-dimethoxybenzidine dihydrochloride, hexachloroethane, isobutene, methyleugenol, oxazepam, C.I. Pigment Red 23, C.I. Acid Red 114, and 4,4'-thiobis(6-t-butyl-m-cresol). The main localization of spontaneously occurring and chemically induced thromboses occurred in the left atrium. The literature survey suggested that chemical-induced atrial thrombosis might be closely related to myocardial injury, endothelial injury, circulatory stasis, hypercoagulability, and impaired atrial mechanical activity, such as atrial fibrillation, which could cause stasis of blood within the left atrial appendage, contributing to left atrial thrombosis. Supplementary data referenced in this paper are not printed in this issue of Toxicologic Pathology. They are available as downloadable files at http://taylorandfrancis.metapress.com/openurl.asp?genre=journal&issn=0192-6233. To access them, click on the issue link for 33(5), then select this article. A download option appears at the bottom of this abstract. In order to access the full article online, you must either have an individual subscription or a member subscription accessed through www.toxpath.org.

Relative Thromboembolic Risks Associated with COX-2 Inhibitors

OBJECTIVE

To evaluate the clinical literature on cyclooxygenase-2 (COX-2) inhibitors to determine whether a greater incidence of thromboembolic events is universal within the drug class.

DATA SOURCES

A MEDLINE search was conducted (1996–March 2005) for key articles in the English language assessing the efficacy or safety of these agents.

STUDY SELECTION AND DATA EXTRACTION

Randomized, double-blind, and controlled trials, as well as case–control and retrospective cohort studies, that assessed the cardiovascular safety of COX-2 inhibitors were reviewed.

DATA SYNTHESIS

Seventeen published studies were reviewed, and the cardiovascular safety data were extracted from each trial. The mechanism by which COX-2 inhibitors may induce a thromboembolic event is likely multifactorial involving (1) COX-2–specific isoform binding affinity, (2) drug dose, (3) duration of therapy, and (4) cardiovascular risk profile of the patient. Evidence supports an association between cardiovascular adverse events and the use of rofecoxib, valdecoxib, and celecoxib. However, this risk is not equally distributed among the drugs. Given the relative paucity of data, lumiracoxib and etoricoxib cardiovascular effects remain uncertain.

CONCLUSIONS

Each COX-2 inhibitor has a unique cardiovascular risk profile. Based on the current evidence, celecoxib is the safest COX-2 inhibitor when prescribed appropriately in the lowest possible dose for the shortest duration in the ideal target population.

Drug Insight: cyclo-oxygenase 2 inhibitors and cardiovascular risk—where are we now?

Cyclo-oxygenase (COX) 1 mediates the production of thromboxane A2 in platelets, leading to platelet aggregation and vasoconstriction. Conversely, COX2 catalyzes endothelial prostacyclin synthesis, which effectively counteracts thromboxane A2, triggering vasodilation and platelet inhibition. Selective COX2 inhibitors decrease prostacyclin production, potentially disrupting homeostasis and creating a prothrombotic state. The VIGOR study findings of increased cardiovascular risk with rofecoxib were subsequently confirmed by large meta-analyses, observational studies and recent APPROVe trial publication. The APC trial findings of increased cardiovascular risk with Celebrex (celecoxib) conflict with those in the ADAPT trial, the upcoming PreSAP publication, a case-control study by Graham et al. and prior large clinical trials, meta-analyses and observational studies of this drug. Therefore, while an adverse class effect is a possibility for COX2 inhibitors, the published data are inconsistent. Baseline cardiovascular risk in patients might contribute significantly to these findings. In light of the negative Vioxx (rofecoxib) publicity, however, COX2 inhibitors might forever remain underinvestigated. The relative selectivity of these compounds for COX2 is extremely variable, casting significant doubt on the class-effect hypothesis. Improved endothelial function has also been reported with celecoxib, leading to endothelium-dependent vasodilation, and associated decreases in C-reactive protein and LDL cholesterol. The addition of meloxicam to low-dose aspirin and heparin has improved clinical outcomes after acute coronary syndromes. These are the first studies suggesting improvement in endothelial function and reduction of inflammation with COX2 inhibition. Thus, more randomized controlled trials are needed to study the relative cardiovascular effects of different COX2 inhibitors, alone and in combination with aspirin.

Selective inhibition of cyclooxygenase-2 enhances platelet adhesion in hamster arterioles in vivo

BACKGROUND

Selective inhibitors of cyclooxygenase-2 (Cox-2) are reported to cause cardiovascular side effects in patients at risk. However, direct proof of prothrombotic effects of these drugs is lacking. We investigated in the microcirculation in vivo whether selective inhibition of Cox-2 induces platelet activation.

METHODS AND RESULTS

The behavior of fluorescence-labeled human platelets was studied in hamster arterioles (dorsal skinfold chamber) by intravital microscopy. Transient platelet-vessel wall interactions (PVWIs), firm platelet adhesion to the vessel wall, and vessel occlusion after FeCl3-induced wall injury were analyzed as platelet activation parameters. In vitro experiments in human umbilical vein endothelial cells (HUVECs) were performed to assess specific effects of Cox-2 inhibition on platelet adhesion under shear stress (16 dyn/cm2) and on endothelial release of 6-ketoprostaglandin (PG) F(1alpha). Selective inhibition of Cox-2 (NS-398, 0.5 mg/kg) increased platelet adhesion to the vessel wall in vivo (11.9+/-3.9 platelets/mm2; controls, 1.4+/-1.4 platelets/mm2, P<0.05) and platelet adhesion after ADP stimulation in vitro. PVWIs were significantly enhanced in NS-398-treated animals, which were reduced by platelet pretreatment with aspirin (5 mg/kg) or iloprost (1 nmol/L). Inhibition of Cox-2 reduced levels of 6-keto-PGF1alpha in vivo and in HUVEC supernatants. Time to occlusion after vessel wall injury was significantly shortened by NS-398 (125.4+/-13.6 seconds in NS-398-treated animals versus 270.8+/-46 seconds in controls; P<0.01).

CONCLUSIONS

Selective inhibition of Cox-2 reduces 6-keto-PGF(1alpha) endothelial release, increases PVWIs, and increases firm platelet adhesion in hamster arterioles. Moreover, it leads to faster occlusion of damaged microvessels. Thus, selective inhibition of Cox-2 may trigger thrombotic events by diminishing the antiplatelet properties of the endothelium.

Benefits of optimising drug treatment in home-dwelling elderly patients with coronary artery disease

Coronary artery disease (CAD) is prevalent in the elderly and often leads to disability. Consequently, strategies for optimising the prevention and treatment of CAD in the elderly are important from both the individual and societal perspectives. Although it is common knowledge that the elderly are heavy consumers of drugs, there is evidence to show that there is under-prescribing of evidence-based medical therapies in the home-dwelling elderly coronary patient and there may be overuse of some non-evidence-based (antioxidants) and purely symptomatic treatments. In particular, aspirin (acetylsalicylic acid), beta-adrenoceptor antagonists, ACE inhibitors and HMG-CoA reductase inhibitors are under-utilised. Although the evidence base is largely drawn from trials including patients younger than 75 years, it is reasonable to assume that the data applies to patients aged over 75 years and that better use of evidence-based medicines would provide benefits to the home-dwelling aged patient. Evidence from the few multifactorial studies available suggest possible benefits including reduction of cardiovascular events, less disability and better quality of life in old age. At the societal level, this would be reflected in fewer hospitalisations and institutionalisations, which means decreased cost of elderly care.

Effets rénaux et cardiovasculaires des anti-inflammatoires non stéroïdiens et des coxibs

HYPERKALIEMIA AND RENAL FAILURE: Nonsteroidal anti-inflammatory drugs (NSAIs) may induce hyperkaliemia and renal failure. With regard to these complications, the notion of a risk factor is fundamental. Selective cyclooxygenase-2 inhibitors (Cox-2) do not provide any notable advantages with regard to the incidence of hyperkaliemia and renal failure. OEDEMA AND BLOOD PRESSURE: The NSAIs provoke salt-water retention which is responsible for oedema in 2 to 5% of patients (here again the notion of a risk factor is important). The salt-water retention is implied in the increase in blood pressure and the decompensation of heart failure. It has been shown that the incidence of oedema and the increase in blood pressure was significantly reduced with celecoxib compared with rofecoxib. This might have a crucial impact on the mean and long term follow-up of cardiovascular risk in these patients.

CARDIOVASCULAR RISK

The results of the VIGOR study that demonstrated an increase in risk of myocardial infarction with rofecoxib, can probably be explained by an anti-thrombotic effect of naproxene, the high dose of rofecoxib used, the type of patients included or the fact that aspirin had been contraindicated. A recent study suggested that the cardiovascular risk was greater with rofecoxib than with celecoxib and with NSAIs when the dose of rofecoxib used was greater than 25mg/day. In this case control study, the cardiovascular risk was identical with celecoxib and NSAIs, whatever the dose used, but increased with a relative risk rate of 1.7 with the doses of rofecoxib greater than 50mg/day. In cases treated with aspirin Some NSAIs can reduce the anti-aggregant effects of aspirin whereas this effect is not observed with Cox-2 selective inhibitors. Hence, the latter should be the pharmacological agents of choice in patients treated with aspirin.

COX-2 inhibitors selectively block prostacyclin synthesis in endotoxin-exposed vascular smooth muscle cells

High levels of prostacyclin (PGI2; measured as 6-keto-PGF1alpha) have been reported in patients under septic shock. Because this was at variance with our previous findings of nitration and inhibition of PGI2 synthase by endotoxin (LPS) in the endothelium, we examined the role of vascular smooth muscle as an alternative source of PGI2. Bovine aortic smooth muscle cells (SMC) in passage 1 contained high levels of PGI2 synthase but no activity and no detectable levels of COX-1 or COX-2. LPS exposure for 3 h caused COX-2 mRNA and protein levels to rise during 8 h together with a large increase in PGI2 synthase activity. In contrast, cytokines lead to only a moderate increase of both PGI2 and PGE2. Specific COX-2 inhibitors completely blocked PGI2 formation but PGE2 synthesis only partially. Unexpectedly, *NO formation remained low over 6-8 h, which may be a reason for the lack of nitration and inhibition of prostacyclin synthase in LPS exposed SMC. Our results can explain the clinical observation of severe hypotension in progressive stages of septic shock as a mechanism to compensate endothelial dysfunction. According to our data, the use of COX-2-specific inhibitors may not be advisable in septic patients. In contrast, administration of COX-1-specific blockers could prevent platelet aggregation during progressed stages of endotoxic shock.

Hypoxia induces myocyte-dependent COX-2 regulation in endothelial cells: role of VEGF

There is increasing evidence that cyclooxygenase (COX)-2 possess both angiogenic and cardioprotective properties. We examined the effects of hypoxic cardiac myocytes (H9c2 cells) on COX-2 expression in human umbilical vein endothelial cells (HUVECs) to determine the pathway involved in COX-2 regulation. The medium from hypoxic (<1% O2) cardiac myocytes (HMCM) or normoxic cardiac myocytes (21% O2) was added to HUVEC cultures. HMCM induced a transient increase of COX-2 mRNA expression at 1 and 3 h without affecting the COX-1 mRNA level. A similar effect also observed in HMCM from cultured primary cardiac myocytes (rat neonatal cardiac myocytes). The increased COX-2 mRNA was associated with a time-dependent increase in COX-2 protein expression. COX-2 was significantly induced by VEGF (4.86 +/- 1.03-fold) and IL-1beta (3.93 +/- 0.89-fold) and slightly increased by TNF-alpha but not by FGF2, IGF-1, or PDGFs. Analysis of proteins secreted in HMCM showed increased levels of VEGF but not IL-1 beta or TNF-alpha. The HMCM-induced COX-2 expression was inhibited by the addition of an anti-VEGF neutralizing antibody. VEGF induced endothelial cell COX-2 expression by both increasing COX-2 transcription and prolonging the COX-2 mRNA half-life. Furthermore, staurosporine, a nonselective PKC inhibitor, prevented the induction of VEGF by hypoxia. Both a selective PKC-alpha and -beta inhibitor and an inducible nitric oxide synthase (NOS) inhibitor decreased the induction of COX-2 by HMCM and VEGF. Finally, HMCM-induced upregulation of COX-2 was accompanied by upregulation of PGI2 and PGE2. These results suggest that VEGF is one of the principal factors produced by hypoxic myocytes that is responsible for the induction of endothelial cell COX-2 expression. This process likely involves both PKC and NOS pathways. Our findings have important implications regarding the cardiac protection of COX-2 in ischemic heart disease.

Effect of cyclooxygenase-2 inhibition with rofecoxib on endothelial dysfunction and inflammatory markers in patients with coronary artery disease

OBJECTIVES

The aim of this study was to determine whether selective cyclooxygenase-2 (COX-2) inhibition with rofecoxib can modulate endothelial dysfunction and levels of circulating inflammatory markers in patients with established coronary artery disease (CAD).

BACKGROUND

Expression of COX-2 is upregulated in atherosclerosis. Thus, it has been hypothesized that COX-2 may contribute to atherogenesis by producing eicosanoids, which mediate vascular inflammation and endothelial dysfunction.

METHODS

In a randomized, double-blind, placebo-controlled, parallel-design trial, we studied the vascular effects of rofecoxib on brachial artery vasoreactivity and inflammatory markers in 60 patients with angiographically proven CAD who were taking concomitant low-dose aspirin. Patients were randomly assigned to receive either rofecoxib (25 mg/day; n = 30) or placebo (n = 30) for eight weeks. Brachial artery endothelium-dependent flow-mediated dilation (FMD), endothelium-independent nitroglycerin-mediated dilation (NMD), and inflammatory markers (i.e., high-sensitivity C-reactive protein [CRP], soluble intercellular adhesion molecule-1 [sICAM-1], and soluble interleukin-6 receptor [sIL-6r]) were measured at baseline and after eight-week follow-up.

RESULTS

Baseline clinical characteristics were similar in the two groups. After eight weeks of treatment, FMD did not significantly change in either the rofecoxib or placebo group (4.0 +/- 3.0% to 4.0 +/- 3.8% vs. 2.7 +/- 2.7% to 3.1 +/- 2.7%, respectively; p = 0.6 by two-way analysis of variance). Similarly, NMD remained unchanged in both groups. Levels of CRP, sICAM-1, and sIL-6r were not significantly altered in either the rofecoxib or placebo group.

CONCLUSIONS

The addition of selective COX-2 inhibition with rofecoxib did not appear to have any favorable or adverse effects on endothelial dysfunction or vascular inflammation in patients with CAD using concomitant low-dose aspirin.

Cyclooxygenase-2 Inhibitors

Background and Summary— Selective cyclooxygenase (COX)-2 inhibitors are increasingly being used in place of “conventional” nonsteroidal anti-inflammatory drugs (NSAIDs). This is because they are just as effective as NSAIDs in relieving arthritic pain and yet less gastrotoxic. However, the cardiovascular safety of selective COX-2 inhibitors has been questioned because they selectively reduce prostacyclin production, thus disrupting the normal homeostatic balance and promoting a prothrombotic state. These theoretical concerns appear to be supported by the results of clinical trials demonstrating an increased risk of myocardial infarction with COX-2 inhibitors compared with a conventional NSAID, and indirect comparisons of the rates of myocardial infarction among patients treated with a selective COX-2 inhibitor compared with aspirin in different trials. However, emerging data from animal, experimental and clinical studies suggest that COX-2 is atherogenic and thrombogenic, and that selective COX-2 inhibitors may be cardioprotective. Meta-analyses of randomized trials of selective COX-2 inhibitors compared with placebo have demonstrated no excess of cardiovascular events among patients allocated COX-2 inhibitors, and preliminary data from a randomized controlled trial of the selective COX-2 inhibitor meloxicam, in patients with acute coronary syndrome who were treated with aspirin, demonstrated a reduction in cardiovascular events among patients allocated the COX-2 inhibitor.

Conclusions— Continuing uncertainty regarding the direction and magnitude of any cardiovascular effects of selective COX-2 inhibitors, coupled with their widespread and increasing use, mandates prospective randomized evaluation of their efficacy and safety in patients at increased risk of future cardiovascular events.

Adverse renal effects of anti-inflammatory agents: evaluation of selective and nonselective cyclooxygenase inhibitors

Conventional nonsteroidal anti-inflammatory drugs (NSAIDs), i.e. nonselective cyclooxygenase COX inhibitors have well-documented nephrotoxicity. Adverse renal effects occur because of inhibition of the synthesis of cyclooxygenase-derived prostaglandins which act to modulate pathologic processes that would normally impair various renal functions. The introduction of the selective COX-2 inhibitors raised hope that this class of drugs would reduce injury in both the gastrointestinal tract and the kidneys. Animal and human data, however, suggest that COX-2 synthesized prostaglandins are important in the modulation of renal physiology during adverse conditions. Hence, it appears that these drugs are equal in causing nephrotoxicity as the nonselective COX inhibitors.

Cyclooxygenase-2 inhibitors: is there an association with coronary or renal events?

The article is concerned with the effects of specific cyclooxygenase-2 (COX-2) inhibitors and their relationship to thrombotic cardiovascular events and to renal disease. Clinical and experimental aspects of COX-2-specific inhibitors are cited. A COX-2 inhibitor, celecoxib, interferes with myocardial prostacyclin production and also produces hypertension. Data have shown that in animal experiments, celecoxib also lowers myocardial prostaglandin concentration but fails to inhibit thromboxane concentration to the same degree. In the kidney, celecoxib can result in glomerular and interstitial nephritis or papillary necrosis. As in infarcted heart muscle, the COX-2-specific inhibitor celecoxib causes a significant decline in prostaglandin in the renal medulla. It was concluded from both clinical and experimental findings that COX-2 inhibitors can cause thrombotic cardiovascular events as well as renal disease. For these reasons, care should be exercised in administering specific COX-2 inhibitors to patients with pre-existing cardiac or renal disease.

Opioid and non-opioid analgesics

Opioids are the most potent analgesics. Toxicity results either from effects mediated by variation in affinity and intrinsic efficacy at specific opioid receptors or, rarely, from a direct toxic effect of the drugs. For some adverse effects, opioids exhibit a 'dual pharmacology' whereby these effects are usually observed only in pain-free individuals, and are not seen in patients in pain. Paracetamol, although generally very safe in therapeutic doses, displays potentially fatal toxicity in overdose requiring specific treatment. Non-steroidal anti-inflammatory drugs (NSAIDs) are known to act by inhibiting COX-1 and COX-2 isoenzymes to various degrees. Toxicity arises primarily from undesired inhibition at these enzyme sites. Knowledge of the mechanism of action of these drugs is fundamental to the understanding of their potential for toxicity, the details of which are still emerging.