Selective Cyclo-Oxygenase-2 Inhibitors and Myocardial Infarction

Effects of Arachidonic Acid Metabolites on Cardiovascular Health and Disease

Arachidonic acid (AA) is an essential fatty acid that is released by phospholipids in cell membranes and metabolized by cyclooxygenase (COX), cytochrome P450 (CYP) enzymes, and lipid oxygenase (LOX) pathways to regulate complex cardiovascular function under physiological and pathological conditions. Various AA metabolites include prostaglandins, prostacyclin, thromboxanes, hydroxyeicosatetraenoic acids, leukotrienes, lipoxins, and epoxyeicosatrienoic acids. The AA metabolites play important and differential roles in the modulation of vascular tone, and cardiovascular complications including atherosclerosis, hypertension, and myocardial infarction upon actions to different receptors and vascular beds. This article reviews the roles of AA metabolism in cardiovascular health and disease as well as their potential therapeutic implication.

Targeting ALDH2 for Therapeutic Interventions in Chronic Pain-Related Myocardial Ischemic Susceptibility

Clinical observations have demonstrated a link between chronic pain and increased ischemic heart disease mortality, but the mechanisms remain elusive. Reactive aldehydes have recently been confirmed as a new player in pain pathologies, while our previous study demonstrated that reactive aldehydes (4-HNE) induced carbonyl stress contributing to myocardial ischemic intolerance. The aim of this study was to explore whether chronic pain increases susceptibility to myocardial ischemia/reperfusion (MI/R) injury and to investigate the underlying mechanisms focusing on toxic aldehyde and carbonyl stress.

Methods: Chronic pain was induced by chronic compression of the dorsal root ganglion (CCD). After 2 weeks CCD, aldehyde dehydrogenase (ALDH2) KO or wild-type (WT) littermate mice were then subjected to in vivo MI/R.

Results: In CCD-WT mice, heightened nociception paralleled circulating aldehyde (4-HNE) accumulation and cardiac protein carbonylation. Mechanistically, CCD-induced 4-HNE overload provoked cardiac Sirtuin 1 (SIRT1) carbonylative inactivation and inhibited Liver kinase B1 (LKB1) - AMP-activated protein kinase (LKB1-AMPK) interaction, which resulted in exacerbated MI/R injury and higher mortality compared with non-CCD WT mice. ALDH2 deficiency further aggravated CCD-induced susceptibility to MI/R injury. Exogenous 4-HNE exposure in peripheral tissue mimicked chronic pain-induced aldehyde overload, elicited sustained allodynia and increased MI/R injury. However, cardiac-specific ALDH2 upregulation by AAV9-cTNT-mediated gene delivery significantly ameliorated chronic pain-induced SIRT1 carbonylative inactivation and decreased MI/R injury (minor infarct size, less apoptosis, and improved cardiac function).

Conclusion: Collectively, chronic pain-enhanced carbonyl stress promotes myocardial ischemic intolerance by SIRT1 carbonylative inactivation and impairment of LKB1-AMPK interaction. ALDH2 activation and prevention of protein carbonylation may be a potential therapeutic target for myocardial ischemic vulnerability in chronic pain patients. Our results newly provided overlapping cellular mechanisms of chronic pain and myocardial dysfunction interplay.

Risk reduction strategies in ischaemic stroke : the role of antiplatelet therapy

Stroke is a common and serious disorder, and is a leading cause of disability and death in adults. Transient ischaemic attacks are now recognised as being common precursors of stroke, with a high risk of subsequent vascular events. The majority of strokes are ischaemic in origin, and are typically due to athero-thrombosis/microatheromatosis involving a large or small cerebral blood vessel or to an embolic event. Owing to the diffuse nature of atherothrombosis, these patients are at risk of ischaemic events in other vascular beds. Options for treating patients with acute ischaemic stroke are very limited; therefore prevention is a key strategy for reducing the risk of recurrent stroke and other vascular events. Treatment of risk factors such as hypertension, diabetes mellitus, smoking and obesity is an important approach for stroke prevention. Platelets are involved in the development of thrombi and emboli, making antiplatelet therapy an important preventive strategy. Antiplatelet agents are effective in preventing recurrent ischaemic stroke and other vascular ischaemic events, such as myocardial infarction and vascular death. In some cases, anticoagulants may be effective in preventing ischaemic stroke recurrence. Carotid endarterectomy can reduce stroke risk in patients with moderate- or high-grade carotid artery stenosis. Choosing the most appropriate therapy for the individual patient is key to optimising stroke prevention.

Induction of differentiation of human leukemia cells by combinations of COX inhibitors and 1,25-dihydroxyvitamin D3 involves Raf1 but not Erk 1/2 signaling

Differentiation therapy of cancer is being explored as a potential modality for treatment of myeloid leukemia, and derivatives of vitamin D are gaining prominence as agents for this form of therapy. Cyclooxygenase (COX) inhibitors have been reported to enhance 1,25-dihydroxyvitamin D(3) (1,25D)-induced monocytic differentiation of promyeloblastic HL60 cells, but the mechanisms of this effect are not fully elucidated, and whether this potentiation can occur in other types of myeloid leukemia is not known. We found that combination treatment with 1,25D and non-specific COX inhibitors acetyl salicylic acid (ASA) or indomethacin can robustly potentiate differentiation of other types of human leukemia cells, i.e., U937, THP-1, and that ASA +/- 1,25D is effective in primary AML cultures. Increased cell differentiation is paralleled by arrest of the cells in the G(1) phase of the cell cycle, and by increased phosphorylation of Raf1 and p90RSK1 proteins. However, there is no evidence that this increase in phosphorylation of Raf1 is transmitted through the ERK module of the MAPK signaling cascade. Transfection of small interfering (si) RNA to Raf1 decreased differentiation of U937 cells induced by a combination of ASA or indomethacin with 1,25D. However, phosphorylation levels of ERK1/2, though not of p90RSK, were increased when P-Raf1 levels were decreased by the siRNA, suggesting that in this system the ERK module does not function in the conventional manner. Identification of the strong antiproliferative activity of ASA/1,25D combinations associated with monocytic differentiation has implications for cancer chemoprevention in individuals who have a predisposition to myeloid leukemia.

Cyclo-oxygenase-2 and its inhibition in cancer: is there a role?

Despite recent improvements in chemotherapy and radiation therapy in cancer management with the addition of biological agents, novel treatment approaches are needed to further benefit patients. Cyclo-oxygenase (COX)-2 inhibition represents one such possibility. COX-2 is an enzyme induced in pathological states such as inflammatory disorders and cancer, where it mediates production of prostanoids. The enzyme is commonly expressed in both premalignant lesions and malignant tumours of different types. A growing body of evidence suggests an association of COX-2 with tumour development, aggressive biological tumour behaviour, resistance to standard cancer treatment, and adverse patient outcome. COX-2 may be related to cancer development and propagation through multiple mechanisms, including stimulation of growth, migration, invasiveness, resistance to apoptosis, suppression of the immunosurveillance system, and enhancement of angiogenesis. Epidemiological data suggest that NSAIDs and selective COX-2 inhibitors might prevent the development of cancers, including colorectal, oesophageal and lung cancer. Preclinical investigations have demonstrated that inhibition of this enzyme with selective COX-2 inhibitors enhances tumour response to radiation and chemotherapeutic agents. These preclinical findings have been rapidly advanced to clinical oncology. Clinical trials of the combination of selective COX-2 inhibitors with radiotherapy, chemotherapy or both in patients with a number of cancers have been initiated, and preliminary results are encouraging. This review discusses the role of COX-2, its products (prostaglandins) and its inhibitors in tumour growth and treatment.

Channelling of COX-2 inhibitors to patients at higher gastrointestinal risk but not at lower cardiovascular risk: the Cox2 inhibitors and tNSAIDs description of users (CADEUS) study

PURPOSE

To describe the characteristics of users of cyclo-oxygenase (COX)-2 inhibitors and traditional nonselective non-steroidal anti-inflammatory drugs (tNSAIDs) in France.

METHODS

Between 1 August 2003 and 31 July 2004, patients who received at least one dispensing of celecoxib, rofecoxib or tNSAIDs were randomly sampled with a 1:1:2 target ratio within the French National Healthcare Insurance database. Patients and prescribers were asked to fill a questionnaire on socio-demographic characteristics, NSAID indication and use and previous medical history. For each respondent, healthcare resources used in the 6 months before inclusion were extracted from the database. Multivariate logistic regression was used to study the determinants of a first COX-2 inhibitor dispensing.

RESULTS

Of the 45 217 patients included, 13 065 COX-2 inhibitors and 13 553 tNSAID users had prescriber data. Ninety seven per cent of COX-2 inhibitor prescriptions were for 'rheumatological' indications, whereas 37% of tNSAIDs use was for benign diseases (n = 2643) or analgesia (n = 2318). Among patients with rheumatological indications (n = 4730) and a first COX-2 inhibitor (n = 2427) or tNSAID (n = 2303) dispensing, multivariate analysis of factors associated with COX-2 inhibitors dispensing showed that, compared to new tNSAID users, new COX-2 inhibitor users were older, more often female, on sick leave or unemployed. COX-2 use was also associated with previous gastrointestinal history and previous gastroprotective agent dispensing, but not with previous cardiovascular (CV) history.

CONCLUSION

The choice of NSAID depended largely on indication and on previous gastrointestinal history, in line with the recommendations of the French health authorities. Possible knowledge of CV risk associated with COX-2 inhibitors did not influence prescribing.

Impact of Acute Pain and Its Management for Thoracic Surgical Patients

Perioperative analgesia for thoracotomy has evolved in concert with increasing knowledge of the impact of pain on recovery, the origin of this pain, and new methods for treating it. Thoracic surgery is one of the few areas where there is more general agreement between surgeons and anesthesiologists as to the importance of aggressive pain management, often with an indwelling epidural catheter left in place until after thoracostomy tube removal. The reasons for this agreement is that it has become increasingly clear to both specialties that pain puts patients with decreased pulmonary reserve who undergo thoracotomy at greater risk for morbidity. Future studies need to examine drugs or drug combinations that can lead to further reductions in the often intense pain that patients receiving aggressive epidural analgesia still experience. Studies directed at finding interventions capable of reducing the rate of long-term postthoracotomy pain still need to be performed.

Do some inhibitors of COX-2 increase the risk of thromboembolic events?: Linking pharmacology with pharmacoepidemiology

Inhibitors of the cyclo-oxygenase (COX)-2 isoenzyme were developed with the expectation that their use would be accompanied by a reduction in adverse reactions thought to be mediated through COX-1 compared with conventional nonselective NSAIDs. However, the results of some clinical studies and other evidence have led to the hypothesis that use of COX-2 inhibitors may contribute to an increased risk of adverse thromboembolic (TE) events. In this review, we have evaluated the evidence from small-scale in vitro and in vivo pharmacological studies, clinical trials and large-scale pharmacoepidemiological studies and commented on the relationship between the pharmacological characteristics related to thromboembolic events and the clinical effects in large-scale clinical trials and pharmacoepidemiological studies. Overall, the pharmacological evidence suggests that a prothrombotic effect of COX-2 selective inhibitors is plausible. To date, despite the results from the Vioxx Gastrointestinal Outcome Research (VIGOR) study from which the clinical concern regarding cardiovascular TE risk arose, the published data from other randomised controlled trials (RCTs), retrospective observational studies and spontaneous reporting schemes provide a conflicting body of evidence on the TE risk with COX-2 inhibitors. Concerns that COX-2 inhibitors may be associated with prothrombotic effects remain and these need to be addressed in large scale, RCTs designed specifically to investigate the possibility of an excess of adverse cardiovascular outcomes in users of some or all selective COX-2 inhibitors, both with and without concomitant low-dose aspirin (acetylsalicylic acid). Consideration must also be given to other pathophysiological mechanisms for potential cardiovascular risk linked with inhibition of COX-2. In view of the evidence reviewed, it is recommended that selective COX-2 inhibitors should be prescribed with caution, only in patients with conditions for which these drugs have proven efficacy and with careful monitoring of outcomes and adverse events. This is particularly important in the elderly, in patients with cardiovascular/renal disease and in patients with other risk factors that might predispose them to adverse events.

Benefit-risk assessment of rofecoxib in the treatment of osteoarthritis

NSAIDs are widely used to treat pain and inflammation in osteoarthritis. Their use in this indication is generally intermittent and fluctuates with the intensity of the disease. Nonetheless, success of the therapy is frequently limited by injury to the gastrointestinal mucosa and complications such as bleeding, ulceration and perforation. A careful and detailed evaluation of these aspects in regard to the newly introduced NSAIDs is of considerable clinical importance. This review focuses on the NSAID rofecoxib, one of the selective cyclo-oxygenase (COX)-2 inhibitors, which are claimed to be as effective as nonselective NSAIDs with better gastrointestinal tolerability. Indeed, phase II, phase III and epidemiological studies have revealed that the efficacy of rofecoxib is comparable to that of conventional NSAIDs but with lower gastrointestinal toxicity, although this advantage may not be demonstrable in every patient. In patients treated with low-dose aspirin (acetylsalicylic acid) for cardiovascular prophylaxis, celecoxib (another selective COX-2 inhibitor) seems to have no obvious advantages over conventional NSAIDs, and similar conclusions may be applied to rofecoxib. A comparison of NSAID therapy +/- concomitant low-dose aspirin was not a primary outcome in this trial with celecoxib and there is thus a need for further studies which compare the gastrointestinal risk of a selective COX-2 inhibitor plus aspirin versus a conventional NSAID. Recent debate has emerged regarding the cardiovascular safety of rofecoxib. Although there is evidence both for and against higher cardiovascular risk with rofecoxib, a retrospective cohort study recently published suggested that there is no increased risk of acute myocardial infarction in the short-term when compared with non-selective NSAIDs. The renal toxicity of rofecoxib has been thoroughly investigated. Clinical studies revealed renal effects of rofecoxib similar to those of conventional NSAIDs. Since adverse effects increase with the degree of renal impairment, monitoring of renal function should be carried out in patients at risk. Although there are still insufficient data concerning certain important adverse effects of rofecoxib, this drug is becoming an important alternative in the therapy of osteoarthritis, especially in high-risk patients. Clinicians need to weigh up the benefits and risks of rofecoxib on a case-by-base basis.

Inhibiteurs sélectifs de COX-2 : quelle toxicité gastro-duodénale ?

Endoscopic studies have shown that cyclo-oxygenase-1 sparing non steroidal anti-inflammatory drugs (NSAIDs) of the coxib family did not produce more gastroduodenal ulcers than placebo in patients who were free of ulcer at baseline. However, the clinical relevance of these data is disputable. Only celecoxib and rofecoxib have been subject to large scale gastrointestinal outcome studies. Both have been shown to reduce the risk of symptomatic ulcers and ulcer complications (perforation, gastric outlet obstruction, bleeding) by about 50% compared to classical NSAIDs used at their maximum therapeutic doses. However, coxibs appear to retain some residual risk, especially in patients at high risk of developing serious gastrointestinal adverse events. This is the case in patients requiring low dose aspirin for cardiovascular purposes. Whether coxibs are still less toxic to the gastroduodenal tract that non-selective NSAIDs in these patients is controversial. Although coxibs have a superior upper gastrointestinal tolerability relative to traditional NSAIDs, dyspepsia, abdominal pain and nausea remain the major factor limiting their use.

Coxibs, quel réel progrès thérapeutique ? : données pharmacoépidémiologiques récentes

Therapeutic advance is defined by an improvement in effectiveness, safety and/or convenience. In this article, these three criteria were applied to currently marketed coxibs (celecoxib, rofecoxib), using data from clinical trials and pharmacoepidemiological studies. Risk of adverse drug reactions to coxibs, as evaluated by clinical trials, differs from that observed in real medical practice. Rofecoxib and celecoxib exhibit the same profile of adverse drug reactions as the other classical nonsteroidal anti-inflammatory drugs. Coxibs are currently prescribed and too often used outside the studied and approved indications, which clearly increases their cost (already high for society). Currently marketed coxibs do not appear to meet the previously defined criteria for therapeutic advance.

Pharmacological treatment of established rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory condition of unknown aetiology that affects about 1% of the general population. Although the optimal care of RA patients requires various modalities, pharmacotherapy remains the cornerstone of treatment for established RA. The current therapeutic model encourages a step-up approach that safely incorporates several currently available classes of agents: non-steroidal anti-inflammatory drugs, selective cyclo-oxygenase-2 inhibitors, glucocorticoids, disease-modifying anti-rheumatic drugs, and biological agents (tumour necrosis factor-alpha inhibitors and interleukin-1 receptor antagonist). Non-steroidal anti-inflammatory drugs, selective cyclo-oxygenase-2 inhibitors and glucocorticoids, which offer a quick onset of symptom relief, are used mainly as adjunctive therapies. Disease-modifying anti-rheumatic drugs and biologicals have been successful in altering disease outcome and slowing radiographic progression. The indications, efficacy and safety of these agents in clinical trials and practice are reviewed in this chapter.

Adverse events associated with rofecoxib therapy: results of a large study in community-derived osteoarthritic patients

OBJECTIVE

To evaluate the safety profile of rofecoxib, a selective cyclo-oxygenase-2 inhibitor, in patients with osteoarthritis who are receiving care in non-hospital practice settings.

DESIGN

All patients participating in a large 24-week, open-label, nonpharmacological intervention trial were given rofecoxib for painful osteoarthritis of the knee or hip. They started at a dose of 12.5mg once daily for the first month, with the option of increasing to 25mg daily thereafter, if needed for efficacy. Adverse events were closely monitored. We considered all adverse events that occurred during treatment and within 14 days of discontinuation of rofecoxib. PATIENT GROUP STUDIED: 2896 patients (861 males and 2035 females) were involved in the safety analysis. Their mean (SD) age was 66.8 (9.9) years, and 631 patients (21.8%) were aged >/=75 years. There were 913 patients (31.5%) with hypertension and 151 (5.2%) with diabetes mellitus at the start of the study; 78 patients (2.7%) had a prior medical history of angina and/or myocardial infarction. The mean (SD) duration of rofecoxib treatment was 139 (62) days.

RESULTS

A total of 519 patients (17.9%) discontinued rofecoxib. The main reasons for discontinuation were dyspepsia (4.4%), nausea (2.4%) and dizziness (2.1%). The annualised incidence rates (95% CI) of complicated and uncomplicated upper gastrointestinal ulcers, myocardial infarction, and stroke were 1.36 (0.76-2.23), 0.09 (0-0.50) and 0.45 (0.16-1.05), respectively.

CONCLUSION

This study conducted in conditions close to daily practice confirms that the use of rofecoxib is associated with a low rate of serious adverse events in patients with osteoarthritis.

Role of Cyclooxygenase-2 Inhibitors in Combination with Radiation Therapy in Lung Cancer

Cyclooxygenase-2 (COX-2) is an enzyme involved in prostaglandin production in pathologic states such as inflammatory disorders and cancer. The enzyme is often overexpressed in premalignant lesions and cancer of the lung. Overexpression of COX-2 in lung cancer is associated with more aggressive biological tumor behavior and adverse patient outcome. In preclinical studies, inhibition of this enzyme with selective COX-2 inhibitors enhances tumor response to radiation and chemotherapeutic agents. These findings have been rapidly advanced to clinical oncology. Clinical trials of the combination of selective COX-2 inhibitors with radiation therapy, chemotherapy, or both in patients with lung cancer have been initiated and some preliminary results are available. In this review, we describe the relationship between overexpression of COX-2 and lung cancer, the antitumor effect of selective COX-2 inhibitors, discuss the rationale for using selective COX-2 inhibitors combined with radiation therapy and chemotherapy, and summarize current clinical protocols and initial findings.