Renal and cardiovascular effects of selective cyclooxygenase-2 inhibitors

EP2 Receptor Blockade Attenuates COX-2 Upregulation During Intestinal Inflammation

High levels of PGE2 have been implicated in the pathogenesis of intestinal inflammatory disorders such as necrotizing enterocolitis (NEC) and peritonitis. However, PGE2 has a paradoxical effect: its low levels promote intestinal homeostasis, whereas high levels may contribute to pathology. These concentration-dependent effects are mediated by four receptors, EP1-EP4. In this study, we evaluate the effect of blockade of the low affinity pro-inflammatory receptors EP1 and EP2 on expression of COX-2, the rate-limiting enzyme in PGE2 biosynthesis, and on gut barrier permeability using cultured enterocytes and three different models of intestinal injury. PGE2 upregulated COX-2 in IEC-6 enterocytes, and this response was blocked by the EP2 antagonist PF-04418948, but not by the EP1 antagonist ONO-8711 or EP4 antagonist E7046. In the neonatal rat model of NEC, EP2 antagonist and low dose of COX-2 inhibitor Celecoxib, but not EP1 antagonist, reduced NEC pathology as well as COX-2 mRNA and protein expression. In the adult mouse endotoxemia and cecal ligation/puncture models, EP2, but not EP1 genetic deficiency decreased COX-2 expression in the intestine. Our results indicate that the EP2 receptor plays a critical role in the positive feedback regulation of intestinal COX-2 by its end-product PGE2 during inflammation and may be a novel therapeutic target in the treatment of NEC.

Ibuprofen-based advanced therapeutics: breaking the inflammatory link in cancer, neurodegeneration, and diseases

Ibuprofen is a classical nonsteroidal anti-inflammatory drug (NSAID) highly prescribed to reduce acute pain and inflammation under an array of conditions, including rheumatoid arthritis, osteoarthritis, dysmenorrhea, and gout. Ibuprofen acts as a potential inhibitor for cyclooxygenase enzymes (COX-1 and COX-2). In the past few decades, research on this small molecule has led to identifying other possible therapeutic benefits. Anti-tumorigenic and neuroprotective functions of Ibuprofen are majorly recognized in recent literature and need further consideration. Additionally, several other roles of this anti-inflammatory molecule have been discovered and subjected to experimental assessment in various diseases. However, the major challenge faced by Ibuprofen and other drugs of similar classes is their side effects, and tendency to cause gastrointestinal injury, generate cardiovascular risks, modulate hepatic and acute kidney diseases. Future research should also be conducted to deduce new methods and approaches of suppressing the unwanted toxic changes mediated by these drugs and develop new therapeutic avenues so that these small molecules continue to serve the purposes. This article primarily aims to develop a comprehensive and better understanding of Ibuprofen, its pharmacological features, therapeutic benefits, and possible but less understood medicinal properties apart from major challenges in its future application.KEY POINTSIbuprofen, an NSAID, is a classical anti-inflammatory therapeutic agent.Pro-apoptotic roles of NSAIDs have been explored in detail in the past, holding the key in anti-cancer therapies.Excessive and continuous use of NSAIDs may have several side effects and multiple organ damage.Hyperactivated Inflammation initiates multifold detrimental changes in multiple pathological conditions.Targeting inflammatory pathways hold the key to several therapeutic strategies against many diseases, including cancer, microbial infections, multiple sclerosis, and many other brain diseases.

Non-steroidal anti-inflammatory drugs in the environment: Where were we and how far we have come?

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most well-known pharmaceuticals with a broad scope of properties that are widely used in human and veterinary medicine. Because of their extensive utilization, NSAIDs are commonly identified in the environment as trace emerging contaminants. Regardless of vast experience with these drugs, NSAIDs are full of contradictions that trigger major concerns for environmental researchers. A limited understanding on NSAID's occurrence, distribution and eco-toxicological effects have led to an escalated dilemma in the last decade. Thus, a broad-spectrum study covering all aspects of occurrence, detection and removal is required to meet the fundamental levels of knowledge on the effects of NSAIDs in all exposed environmental aspects. Therefore, this paper focuses on classifying the sources and entry points of residual NSAIDs. Further, detecting and regulating their concentrations in both input streams and receiving environments, along with the removal processes of this specific class of emerging compounds, in the direction of developing a management policy is comprehensively reviewed.

Characterization of the Adverse Effects Induced by Acetaminophen and Nonsteroidal Anti-Inflammatory Drugs Based on the Analysis of the Japanese Adverse Drug Event Report Database

Objectives:

Acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) are antipyretic analgesics with established adverse effects (AEs); however, only a few studies have compared their AEs simultaneously. We aimed to compare the AEs of these medications to confirm the respective frequencies of both rare and major AEs.

Methods:

We used a high-quality database for spontaneous adverse drug event reporting in Japan. Data were extracted regarding the AEs of acetaminophen and NSAIDs to compare the tendency of the appearance of those AEs between the drugs. We also performed a principal component analysis using the AE data to assess the characteristics of major AEs.

Results:

Cutaneous disorders and hepatic disorders were the most common AEs induced by acetaminophen and NSAIDs, with gastrointestinal tract disorders also common with NSAID use. Principal component analysis quantitatively showed the tendencies of specific AEs, and it helped demonstrate the characteristics of AEs. Acetaminophen and NSAIDs showed different tendencies in the occurrence of AEs. Each NSAID was plotted based on the tendency of the appearance of major AEs, and AEs were classified by their likelihood of being pharmacological or idiosyncratic.

Conclusions:

These findings may help clinicians select an appropriate drug for patients considering their backgrounds, instead of choosing merely based on the class of the drug, for example, cyclooxygenase selectivity. This selection, based on the characteristic information on AEs occurring in clinical settings, might be more suitable for patients.

Short-Term Non-Steroid Anti-Inflammatory Drug Use in Spondyloarthritis Patients Induces Subclinical Acute Kidney Injury: Biomarkers Study

BACKGROUND

Non-steroid anti-inflammatory drug (NSAID) usage is associated with kidney injury. Rise in serum creatinine (sCr) often represents irreversible process. Thus to assess the early effects of regular NSAID use, we studied sensitive serum and urine biomarkers of kidney injury.

METHODS

In a protocol-based intervention study, 103 subjects were enrolled in 3 mutually exclusive groups. Group 1 included 37 healthy controls having minimal baseline NSAID exposure as per a definition, and group 2 had 41 spondyloarthritis (SpA) patients on regular NSAID therapy for >3 months. Group 3 included 25 SpA patients having minimal NSAID exposure at baseline. Blood and urine samples were collected from all the 3 groups at baseline. Furthermore, group 3 was started on 6-week regular NSAID therapy, and blood and urine samples were re-collected at 1, 6, and 12 weeks. Baseline normal kidney function as per the definition was ensured in all the subjects. Creatinine, neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin-C, and microalbumin were measured in urine and serum samples to assess kidney injury.

RESULTS

Kidney injury biomarkers were 2-3-fold higher in SpA patients using regular NSAID therapy compared to healthy controls and SpA patients having minimal NSAID exposure (uKIM-1 and uNGAL p < 0.0001, sKIM-1 and sNGAL p = 0.001). There was no difference in sCr and estimated glomerular filtration rate using Cockcroft-Gault equation between the groups. In SpA patients started on 6 weeks of regular NSAID (group 3), biomarker levels started rising at week 1 and showed a significant rise at week 6. The levels in the patients that stopped NSAID use at 6 weeks showed reversibility at 12 weeks.

CONCLUSIONS

Regular NSAID use in SpA patients induces subclinical kidney injury represented by rise in biomarkers. These levels start rising as early as 7 days of regular NSAID use and are reversible on stopping the drug.

Possible role for brain prostanoid pathways in the development of angiotensin II-salt hypertension in rats

Prostanoids generated by the cyclooxygenase (COX) pathway appear to contribute to the neurogenic hypertension (HTN) in rats. The first goal of this study was to establish the time frame during which prostanoids participate in ANG II-salt HTN. We induced HTN using ANG II (150 ng·kg(-1)·min(-1) sc) infusion for 14 days in rats on a high-salt (2% NaCl) diet. When ketoprofen pretreatment was combined with treatment during the first 7 days of ANG II infusion, development of HTN and increased neurogenic pressor activity (indexed by the depressor response to ganglion blockade) were significantly attenuated for the entire ANG II infusion period. This suggests that prostanoid generation caused by administration of ANG II and salt leads to an increase in neurogenic pressor activity and blood pressure (BP) via a mechanism that persists without the need for continuing prostanoid input. The second goal of this study was to determine whether prostanoid products specifically in the brain contribute to HTN development. Expression of prostanoid pathway genes was measured in brain regions known to affect neurogenic BP regulation. ANG II-treated rats exhibited changes in gene expression of phospholipase A2 (upregulated in organum vasculosum of the lamina terminalis, paraventricular nucleus, nucleus of the solitary tract, and middle cerebral artery) and lipocalin-type prostaglandin D synthase (upregulated in the organum vasculosum of the lamina terminalis). On the basis of our results, we propose that activation of the brain prostanoid synthesis pathway both upstream and downstream from COX at early stages plays an important role in the development of the neurogenic component of ANG II-salt HTN.

Glomerular haemodynamic profile of patients with Type 1 diabetes compared with healthy control subjects

AIMS

To evaluate the glomerular haemodynamic profile of patients with Type 1 diabetes with either renal hyperfiltration (GFR ≥ 135 ml/min/1.73 m2 ) or renal normofiltration (GFR 90-134 ml/min/1.73 m2 ) during euglycaemic and hyperglycaemic conditions, and to compare this profile with that of a similar group of healthy control subjects.

METHODS

Gomez's equations were used to derive afferent and efferent arteriolar resistances, glomerular hydrostatic pressure and filtration pressure.

RESULTS

At baseline, during clamped euglycaemia, patients with Type 1 diabetes and hyperfiltration had lower mean ± sd afferent arteriolar resistance than both those with Type 1 diabetes and normofiltration (914 ± 494 vs. 2065 ± 597 dyne/s/cm5 ; P < 0.001) and healthy control subjects (1676 ± 707 dyne/s/cm(5) ; p < 0.001). By contrast, efferent arteriolar resistance was similar in the three groups. Patients with Type 1 diabetes and hyperfiltration also had higher mean ± sd glomerular hydrostatic pressure than both healthy control subjects and patients with Type 1 diabetes and normofiltration (66 ± 6 vs. 60 ± 3 vs. 55 ± 3 mmHg; P < 0.05). Similar findings for afferent arteriolar resistance, efferent arteriolar resistance, glomerular hydrostatic pressure and filtration pressure were observed during clamped hyperglycaemia.

CONCLUSION

Hyperfiltration in Type 1 diabetes is primarily driven by alterations in afferent arteriolar resistance rather than efferent arteriolar resistance. Renal protective therapies should focus on afferent renal arteriolar mechanisms through the use of pharmacological agents that target tubuloglomerular feedback, including sodium-glucose cotransporter 2 inhibitors and incretins.

Efficacy and Safety of COX-2 Inhibitors in the Clinical Management of Arthritis: Mini Review

In the clinical management of arthritis, the choice of nonsteroidal anti inflammatory drug (NSAID) remains confusing and controversial. A common practice on the choice of NSAID in clinical management of arthritis is the risk benefit ratio. The main objective of this review is to addresses the main arguments for the pharmacological and clinical use of COX-2 inhibitors in relation to nonselective NSAIDs for the clinical management of arthritis. This review concluded that, both NSAIDs and COX-2 inhibitors are equally effective and are associated with increased risk of GI, renal, and CV, adverse effects. Complete understanding of the patient's comorbid conditions and concomitant medications, coupled with precise monitoring during the treatment, may help to decrease the threat of adverse effects induced by nonselective NSAIDs and selective COX-2 inhibitors.

A polymorphism in the cyclooxygenase 2 gene in type 1 diabetic patients with nephropathy

Diabetic nephropathy (DN), the most serious complication of Type 1 diabetes (DM1), has a strong genetic component. Cyclooxygenase-2 (COX-2), an inducible enzyme by a number of stimuli, has been implicated in pathophysiology of cardiovascular and renal disease, including DN. The allele -765C, of the -765G > C polymorphism (rs20417) in the COX-2 promoter has lower promoter activity compared with the -765G allele and protective effects in cardiovascular disease. This polymorphism was not investigated in patients with DM1 and nephropathy. The study was conducted in 779 Caucasian patients with DM1 and compared to a representative sample of healthy Czech population. The patients demonstrated lower frequencies of the CC genotype (P = 0.005). From the DM1 cohort, 153 patients met the criteria for low risk of the development of DN (LRDN, duration of DM1 > 10 years, normoalbuminuria, normotension) and 139 patients had manifest DN. There were no differences in -765G > C polymorphisms between LRDN and DN patients. Moreover, the C/G allele frequencies did not also differ between the groups. In conclusion, patients with DM1 display lower freqencies of the protective CC genotype as compared to healthy subjects. However, the study did not reveal associations of -765G > C polymorphism with the risk of DN.

Renal hyperfiltration is a determinant of endothelial function responses to cyclooxygenase 2 inhibition in type 1 diabetes

OBJECTIVE

Our aim was to examine the effect of cyclooxygenase 2 (COX2) inhibition on endothelial function in subjects with type 1 diabetes analyzed on the basis of renal filtration status.

RESEARCH DESIGN AND METHODS

Flow-mediated dilation (FMD) was determined in type 1 diabetic subjects and hyperfiltration (glomerular filtration rate >or=135 ml/min/1.73 m(2), n = 13) or normofiltration (glomerular filtration rate >or=135 ml/min/1.73 m(2), n = 11). Studies were performed before and after celecoxib (200 mg daily for 14 days) during euglycemia and hyperglycemia.

RESULTS

Baseline parameters were similar in the two groups. Pretreatment, FMD was augmented in normofiltering versus hyperfiltering subjects during clamped euglycemia (10.2 +/- 5.3% vs. 5.9 +/- 2.3%, P = 0.003). COX2 inhibition suppressed FMD in normofiltering (10.2 +/- 5.3% to 5.8 +/- 3.4%, P = 0.006) versus hyperfiltering subjects (ANOVA interaction, P = 0.003).

CONCLUSIONS

Systemic hemodynamic function, including the response to COX2 inhibition, is related to filtration status in diabetic subjects and may reflect general endothelial dysfunction.

Calcineurin inhibitor nephrotoxicity

The use of the calcineurin inhibitors cyclosporine and tacrolimus led to major advances in the field of transplantation, with excellent short-term outcome. However, the chronic nephrotoxicity of these drugs is the Achilles' heel of current immunosuppressive regimens. In this review, the authors summarize the clinical features and histologic appearance of both acute and chronic calcineurin inhibitor nephrotoxicity in renal and nonrenal transplantation, together with the pitfalls in its diagnosis. The authors also review the available literature on the physiologic and molecular mechanisms underlying acute and chronic calcineurin inhibitor nephrotoxicity, and demonstrate that its development is related to both reversible alterations and irreversible damage to all compartments of the kidneys, including glomeruli, arterioles, and tubulo-interstitium. The main question--whether nephrotoxicity is secondary to the actions of cyclosporine and tacrolimus on the calcineurin-NFAT pathway--remains largely unanswered. The authors critically review the current evidence relating systemic blood levels of cyclosporine and tacrolimus to calcineurin inhibitor nephrotoxicity, and summarize the data suggesting that local exposure to cyclosporine or tacrolimus could be more important than systemic exposure. Finally, other local susceptibility factors for calcineurin inhibitor nephrotoxicity are reviewed, including variability in P-glycoprotein and CYP3A4/5 expression or activity, older kidney age, salt depletion, the use of nonsteroidal anti-inflammatory drugs, and genetic polymorphisms in genes like TGF-beta and ACE. Better insight into the mechanisms underlying calcineurin inhibitor nephrotoxicity might pave the way toward more targeted therapy or prevention of calcineurin inhibitor nephrotoxicity.

Renal hemodynamic effect of cyclooxygenase 2 inhibition in young men and women with uncomplicated type 1 diabetes mellitus

In experimental studies, cyclooxygenase 2 (COX2)-derived vasodilatory prostaglandins play a more prominent role in arterial vasoregulation in females. The gender-dependent effect of COX2 modulation in humans with type 1 diabetes mellitus (DM) is unknown. Accordingly, we examined the renal hemodynamic role of prostaglandins by assessing the response to COX2 inhibition in young men and women with type 1 DM. We also used a graded ANG II infusion to determine whether gender-based differences were mediated by effects of COX2 inhibition on the renin angiotensin system (RAS). We hypothesized that COX2 inhibition would be associated with preferential vasoconstriction in women and would augment their response to ANG II. Baseline renal function and the response to an ANG II infusion were assessed during clamped euglycemia, and again after COX2 inhibition (200 mg celecoxib daily for 14 days) in 12 men and 9 women after 1 wk on a controlled protein and sodium diet. COX2 inhibition was associated with increases in filtration fraction (P = 0.045) and renal vascular resistance and a decline in renal blood flow (P = 0.04) in women compared with men. Before COX2 inhibition, women exhibited a decline in glomerular filtration rate in response to ANG II. COX2 inhibition abolished this effect, whereas the response was not altered in men. In summary, COX2 inhibition was associated with hemodynamic effects that differed based on gender. The ANG II response suggests that with uncomplicated type 1 DM, prostaglandins may contribute to RAS-mediated gender differences. Our results are consistent with experimental data suggesting augmented female prostanoid dependence.

The effect of cyclooxygenase-2 inhibition on renal hemodynamic function in humans with type 1 diabetes

OBJECTIVE

Studies in animal models suggest that cyclooxygenase-2 (COX2) plays a role in the regulation of the renal microcirculation in diabetes. Accordingly, we examined the role of COX2 in the control of renal hemodynamic function and in the renal response to hyperglycemia in humans with uncomplicated type 1 diabetes. We hypothesized that COX2 inhibition would alleviate the hyperfiltration state and would abrogate the hyperglycemia-mediated rise in glomerular filtration rate (GFR). RESEARCH DESIGN AND METHODS; Renal function was assessed during clamped euglycemia and hyperglycemia on 2 consecutive days before and then again after 14 days of COX2 inhibition using 200 mg celecoxib once daily by mouth. For analysis, the cohort was then divided into two groups based on the baseline GFR: 9 subjects exhibited hyperfiltration (GFR >or=135 ml/min per 1.73 m(2)), and 12 subjects exhibited normofiltration (GFR <135 ml/min per 1.73 m(2)).

RESULTS

Under euglycemic conditions, COX2 inhibition resulted in a significant decline in GFR in the hyperfiltration group (150 +/- 5 to 139 +/- 5 ml/min per 1.73 m(2)) but increased GFR in the normofiltration group (118 +/- 5 to 138 +/- 5 ml/min per 1.73 m(2)). COX2 inhibition did not blunt the hyperglycemia-associated rise in GFR in the normofiltration group and was instead associated with an augmented rise in GFR.

CONCLUSIONS

In summary, our results support the hypothesis that COX2 is an important determinant of renal hemodynamic function in subjects with type 1 diabetes. The renal response to COX2 inhibition emphasizes that hyperfiltration and normofiltration are distinct physiological states.

Cyclo-oxygenase-2 inhibition attenuates the progression of nephropathy in uninephrectomized diabetic rats

1. Cyclo-oxygenase (COX)-2 is involved in constitutive production of prostanoids in the kidney and plays a role in the control of renal function and morphology. Renal cortical COX-2 expression and function is increased in experimental models of diabetes (DM). However, pathophysiological roles of this phenomenon in the diabetic kidney have not been fully elucidated. To address this issue, we studied the nephroprotective potential of long-term (16 weeks) COX-2 inhibition in uninephrectomized streptozotocin-diabetic rats (D). 2. Diabetic rats received either a low or high dose of the selective COX-2 inhibitor MF-tricyclic (MF; 1 or 5 mg/kg per day in chow). Another group of D rats received high-dose MF as late intervention starting at 8 weeks of DM (D-MFlate). The effects of treatments were compared with age-matched uninephrectomized diabetic and non-diabetic rats receiving drug-free chow (D-VE and C-VE, respectively). 3. No differences in blood pressure and metabolic control were observed between groups of D rats throughout the study. The D-VE group developed progressive albuminuria and glomerulosclerosis, associated with increased excretion of the thromboxane (TX) A(2) metabolite TxB(2). Treatment with MF attenuated albuminuria in diabetic rats with late intervention, but not in D rats treated with MF from the onset of DM. Moreover, D-MFlate rats demonstrated a significant reduction in the development of glomerulosclerosis. These effects coincided with prevention of diabetes-induced rise in urinary TxB(2) excretion. 4. In conclusion, long-term COX-2 inhibition is associated with modest nephroprotection in uninephrectomized diabetic rats when administered as late intervention. These effects are independent of metabolic control and blood pressure.

Blood pressure effects of COX-2 inhibitors

There has been significant recent interest in the cardiovascular effects of cyclooxygenase 2 (COX-2) selective inhibitors. Whereas much attention has been focused on the putative prothrombotic effect of these agents, their cardiorenal and blood pressure elevating actions may be of equal if not greater importance to cardiovascular risk. COX-2 is widely expressed throughout the kidney, and inhibition of this enzyme is contributory to reduced glomerular filtration, salt and water retention, and blood pressure elevation. The key issues in relation to COX-2 inhibitors and blood pressure are whether these blood pressure-elevating effects are similar to or differ from nonselective nonsteroid anti-inflammatory drugs, whether differences exist among COX-2 inhibitors in regard to blood pressure regulation, and if so, possible mechanisms underlying blood pressure differences between COX-2 inhibitors. With regard to the last issue, possible mechanisms include greater COX-2 selectivity of certain agents such as rofecoxib, the differing half-life of these agents, the carbonic anhydrase activity of celecoxib (which may offset renal-induced salt and water retention), and possible aldosterone modulation by rofecoxib. Finally, and perhaps most important, the issue arises as to whether blood pressure elevation may contribute in whole or in part to the increase in cardiovascular events observed with these agents in some but not all studies. Ultimately, adequately powered, prospective randomized clinical trials assessing relevant cardiovascular endpoints are required to address many of these outstanding questions. Such studies have recently been announced and will commence soon.

Eicosanoids and renal vascular function in diseases

Arachidonic acid metabolites are vital for the proper control of renal haemodynamics and, when not properly controlled, can contribute to renal vascular injury and end-stage renal disease. Three major enzymatic pathways, COX (cyclo-oxygenase), CYP450 (cytochrome P450) and LOX (lipoxygenase), are responsible for the metabolism of arachidonic acid metabolites to bioactive eicosanoids. These eicosanoids can dilate or constrict the renal vasculature and maintain vascular resistance in the face of changing vasoactive hormones. Renal vascular generation of eicosanoids is altered in pathophysiological conditions such as hypertension, diabetes, metabolic syndrome and acute renal failure. Experimental evidence supports the concept that altered eicosanoid metabolism contributes to renal haemodynamic alterations and the development and progression of nephropathy. The possible beneficial renal vascular actions of enzymatic inhibitors, eicosanoid analogues and receptor antagonists have been examined in hypertension, diabetes and metabolic syndrome. This review highlights the roles of renal vascular eicosanoids in the pathogenesis of nephropathy and therapeutic targets for renal disease related to hypertension, diabetes, metabolic syndrome and acute renal failure.

Effects of intrarenal administration of the cox-2 inhibitor parecoxib during porcine suprarenal aortic cross-clamping

The aim of this study was to investigate the effects of intrarenal administration of the cyclooxygenase-2 inhibitor parecoxib during suprarenal aortic cross-clamping. In a prospective, controlled, blinded, randomized manner, 16 anesthetized and mechanically ventilated pigs were instrumented to measure systemic and right kidney hemodynamics, oxygen exchange, and metabolism. During 45 min of suprarenal aortic cross-clamping, animals received 40 mg of parecoxib (n = 8) or vehicle (n = 8) infused continuously into the right renal artery. Hemodynamic and metabolic data, right kidney venous blood, as well as urine samples were obtained before clamping, as well as before and 75 and 195 min after declamping. Clamping transiently increased mean arterial pressure in both groups. Systemic and renal blood flow did not differ between the pre- and postclamping measurements or between groups. Parecoxib attenuated the otherwise significant fall in right kidney creatinine clearance (controls: from 45 [7;111] to 17 [9;22] mL/min; parecoxib: from 39 [3;59] to 27 [11;45] mL/min, P = 0.039 and P = 0.297, respectively versus before clamping, P = 0.021 versus controls at 195 min) and prevented the impairment of renal lactate balance observed in the control group (controls: from 0.5 [-0.8;3.5] to 0.2 [-0.2;0.6] mumol/kg/min; parecoxib: from 0.6 [-1.0;2.0] to 0.4 [-1.2;0.6] mumol/kg/min, P = 0.038 and P = 0.285, respectively, versus before clamping). In conclusion, intrarenal parecoxib infusion beneficially influenced kidney function in this clinically relevant model of suprarenal aortic cross-clamping.

Comparative cardiovascular safety of traditional nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for their anti-inflammatory and analgesic effects. Unfortunately, these drugs are not without toxicity, namely on the gastric mucosa, but also on the cardiovascular system. In this context, the marketing of the coxibs, a new series of NSAIDs that selectively inhibit COX-2, resulted in a large debate around their cardiovascular safety, because they may increase the incidence of myocardial infarction and stroke. The recent suspension of a large, randomised, controlled trial comparing celecoxib, naproxen and placebo in Alzheimer patients (the ADAPT trial) because of an apparent elevated cardiovascular risk in the naproxen group revived the debate on the cardiovascular safety of these drugs, but this time with special emphasis on the effect of traditional nonselective NSAIDs (tNSAIDs). In this paper that reviews and discusses the cardiovascular safety profile of tNSAIDs, essentially naproxen and ibuprofen in view of the most recent experimental and clinical data, the authors note that the published data are quite discordant and one cannot conclude that there is clear evidence to support a cardiovascular hazard from the administration of naproxen or non-naproxen NSAIDs unless additional information is provided. In addition, the results of retrospective case-control studies have to be interpreted very carefully because of the risk of confounding factors that are not always taken into account when subjects were classified either as cases or controls. Thus, in the absence of clear cut data, physicians will have to use traditional NSAIDs (or coxibs) in patients with a high cardiovascular risk on the basis of their common sense rather than on evidence-based medicine. For these patients, one should not forget that an inadequate long-term control of cardiovascular risk factors such as a hypertension, dyslipidaemia, diabetes, smoking and weight excess is more deleterious in terms of cardiovascular mortality than the administration of NSAIDs itself.

Chemoprevention strategies with cyclooxygenase-2 inhibitors for lung cancer

Clinical lung cancer is the ultimate event resulting from a series of genetic and epigenetic alterations in the respiratory epithelium at risk. According to the "field carcinogenesis" theory, these alterations can occur throughout the entire lung. In individuals with a genetic predisposition combined with a sufficient amount of procarcinogenic environmental influences, a few of these sites may eventually progress to malignancies. Recent advances in the understanding of tumor biology have identified new therapeutic targets for lung cancer chemoprevention, among which is cyclooxgygenase (COX)-2. Ample preclinical data suggest that the COX-2/prostaglandin E2 (PGE2) signaling pathway plays a pivotal role in conferring the malignant phenotype. Produced primarily by the action of COX on the free arachidonic acid liberated from membrane phospholipids, overproduction of PGE2, which is predominantly generated by upregulation of COX-2, is associated with a variety of mechanisms known to facilitate tumorigenesis. These mechanisms include abnormal expression of epithelial growth factors, epithelial and microvascular proliferation, resistance to apoptosis, and suppression of antitumor immunity. The lung is one of the major sites of PGE2 production, and previous studies have shown elevated PGE2 levels in bronchoalveolar lavage fluid of patients with bronchogenic carcinoma. In animal models, inhibition of COX-2 and PGE2 synthesis suppresses lung tumorigenesis. These preclinical data suggesting the antineoplastic effect of COX-2 inhibitors provide the basis for several ongoing pilot clinical trials to determine the feasibility of COX-2 inhibition in chemoprevention of bronchogenic carcinoma.

Everolimus treatment downregulates renocortical cyclooxygenase-2 expression in the rat kidney

Based on recent evidence that renal cyclooxygenase-2 (COX-2) gene expression is suppressed by immunosuppressive agents such as cyclosporin A (CsA), tacrolimus and dexamethasone, this study aimed to characterize the effect of the new immunosuppressant everolimus on COX-2 expression in the rat kidney. Oral application of everolimus (3 mg kg(-1) day(-1)) to male Sprague-Dawley rats (175-200 g; n=8) for 7 days lowered COX-2 expression in the rat renal cortex and outer medulla, while COX-2 expression in the inner medulla as well as COX-1 expression remained unaltered. Furthermore, everolimus decreased renocortical prostaglandin (PG) E(2) concentration. Everolimus also attenuated the stimulation of renocortical COX-2 expression by furosemide (12 mg day(-1) for 7 days; s.c. via osmotic minipumps), by low salt intake (0.02% NaCl, wt wt(-1)) or by a combination of low salt intake with the AT(1)-receptor antagonist valsartan (30 mg kg(-1) day(-1); oral). In line with these findings, everolimus decreased renocortical PGE(2) concentration during these treatment maneuvers. Everolimus moderately increased natriuresis and diuresis, while the urinary excretion of PGE(2), 6-keto PGF(1alpha) and thromboxane B(2) was decreased. These findings suggest that everolimus inhibits basal and also stimulated expression of renocortical COX-2 and of tissue prostanoid formation. Since inhibition of renal prostanoid formation by everolimus was associated by an increased rather than decreased natriuresis and diuresis, it appears as if everolimus also inhibits tubular salt and water resorption.

Role of cyclooxygenase-2 inhibitors in postoperative pain management

Cyclooxygenase (COX)-2 inhibitors are as efficacious as nonselective nonsteroidal anti-inflammatory drugs for the treatment of postoperative pain but have the advantages of a better gastrointestinal side-effect profile as well as a lack of antiplatelet effects. There have been recent concerns regarding the cardiovascular side effects of COX-2 inhibitors. Nonetheless, they remain a valuable option for postoperative pain management. The pharmacology of these agents and available studies are reviewed.

Treatment of pain in patients with renal insufficiency: The World Health Organization three-step ladder adapted

The World Health Organization established official recommendations for managing pain in cancer patients. Since then, this stepladder approach has been widely adopted as a conceptual framework to treat all types of pain. However, those guidelines have not been critically evaluated for use in patients with renal insufficiency. In these patients, the questions of drug dosage adjustment and renal toxicity must be considered. This article reviews the pharmacokinetics of major analgesic drugs and data on their use and/or behavior in renal failure and considers their potential nephrotoxicity. Finally, according to available data in the international literature on pharmacokinetics, recommendations for dosage adjustment in patients with renal failure, and their potential nephrotoxicity, the World Health Organization three-step ladder for the treatment of pain was modified and adapted for patients with impaired renal function. Perspective This well-known treatment strategy now adapted for use in patients with renal insufficiency should secure and rationalize pain treatment in those patients.

Nabumetone: therapeutic use and safety profile in the management of osteoarthritis and rheumatoid arthritis

Nabumetone is a nonsteroidal anti-inflammatory prodrug, which exerts its pharmacological effects via the metabolite 6-methoxy-2-naphthylacetic acid (6-MNA). Nabumetone itself is non-acidic and, following absorption, it undergoes extensive first-pass metabolism to form the main circulating active metabolite (6-MNA) which is a much more potent inhibitor of preferentially cyclo-oxygenase (COX)-2. The three major metabolic pathways of nabumetone are O-demethylation, reduction of the ketone to an alcohol, and an oxidative cleavage of the side-chain occurs to yield acetic acid derivatives. Essentially no unchanged nabumetone and < 1% of the major 6-MNA metabolite are excreted unchanged in the urine from which 80% of the dose can be recovered and another 10% in faeces. Nabumetone is clinically used mainly for the management of patients with osteoarthritis (OA) or rheumatoid arthritis (RA) to reduce pain and inflammation. The clinical efficacy of nabumetone has also been evaluated in patients with ankylosing spondylitis, soft tissue injuries and juvenile RA. The optimum oral dosage of nabumetone for OA patients is 1 g once daily, which is well tolerated. The therapeutic response is superior to placebo and similar to nonselective COX inhibitors. In RA patients, nabumetone 1 g at bedtime is optimal, but an additional 0.5-1 g can be administered in the morning for patients with persistent symptoms. In RA, nabumetone has shown a comparable clinical efficacy to aspirin (acetylsalicylic acid), diclofenac, piroxicam, ibuprofen and naproxen. Clinical trials and a decade of worldwide safety data and long-term postmarketing surveillance studies show that nabumetone is generally well tolerated. The most frequent adverse effects are those commonly seen with COX inhibitors, which include diarrhoea, dyspepsia, headache, abdominal pain and nausea. In common with other COX inhibitors, nabumetone may increase the risk of GI perforations, ulcerations and bleedings (PUBs). However, several studies show a low incidence of PUBs, and on a par with the numbers reported from studies with COX-2 selective inhibitors and considerably lower than for nonselective COX inhibitors. This has been attributed mainly to the non-acidic chemical properties of nabumetone but also to its COX-1/COX-2 inhibitor profile. Through its metabolite 6-MNA, nabumetone has a dose-related effect on platelet aggregation, but no effect on bleeding time in clinical studies. Furthermore, several short-term studies have shown little to no effect on renal function. Compared with COX-2 selective inhibitors, nabumetone exhibits similar anti-inflammatory and analgesic properties in patients with arthritis and there is no evidence of excess GI or other forms of complications to date.

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.

The gastrointestinal tolerability of the LOX/COX inhibitor, licofelone, is similar to placebo and superior to naproxen therapy in healthy volunteers: results from a randomized, controlled trial

OBJECTIVES

Concerns exist over the safety of conventional nonsteroidal antiinflammatory drugs (NSAIDs) and selective cyclooxygenase (COX)-2 inhibitors. In experimental models, licofelone, a competitive inhibitor of 5-lipoxygenase (5-LOX) and COX-1/-2, has been shown to have good gastrointestinal and general tolerability and analgesic and antiinflammatory properties. The aim of the present endoscopy trial was to investigate the gastroduodenal tolerability of licofelone compared to placebo and naproxen in healthy volunteers.

METHODS

In this randomized, parallel-group trial, healthy volunteers received licofelone 200 mg b.i.d. (n = 30), licofelone 400 mg b.i.d. (n = 30), naproxen 500 mg b.i.d. (n = 30), or placebo (n = 31). Tolerability was assessed by gastro/duodenoscopy following 4 wk of treatment. Laboratory parameters and the incidence of ulcers and adverse events were recorded.

RESULTS

Ulcers were observed in 20% of the naproxen-treated volunteers, compared with 0% of those receiving licofelone 200 mg, licofelone 400 mg, and placebo (p= 0.024). Posttreatment mean gastric Lanza scores were similar for volunteers who received placebo or either dose of licofelone, while Lanza scores were significantly worse following naproxen therapy (p < 0.00001). The gastric mucosa was normal in 93%, 89%, and 90% of volunteers who received licofelone 200 mg, licofelone 400 mg, or placebo, respectively, compared with 37% of volunteers receiving naproxen. The incidence of adverse events did not differ significantly between licofelone 200 mg or naproxen therapy. No clinically relevant changes in laboratory parameters were observed with licofelone or naproxen therapy.

CONCLUSIONS

The results from this trial indicate that licofelone has a potential gastrointestinal safety advantage over conventional NSAID therapy, as licofelone was associated with significantly superior gastric tolerability and a lower incidence of ulcers compared with naproxen in healthy volunteers. Further trials will be required to investigate the safety and efficacy of licofelone in the treatment of diseases such as osteoarthritis.

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.

Blood Pressure Elevation with Rofecoxib in Older Adults

Objective:

To report blood pressure elevation associated with rofecoxib use in 2 older adults.

Case Summaries:

Two patients, aged 75 and 94 years, were prescribed rofecoxib for osteoarthritis pain. After the initiation of therapy, an elevation in systolic blood pressure measurement ≥17 mm Hg was observed. Upon withdrawal of rofecoxib, blood pressure in one patient returned to baseline measurements. In the second patient, sustained rofecoxib use resulted in blood pressure elevation and change in antihypertensive therapy.

Discussion:

It is well known that even a small elevation in blood pressure can significantly increase a person's risk for cardiovascular events. However, little is known about the potential magnitude of blood pressure elevation with the use of cyclooxygenase-2 inhibitors in the older adult population. In 2 older adults with osteoarthritis and hypertension, rofecoxib potentially led to a substantial elevation in blood pressure. In each case, adjustments of respective therapeutic regimens were made. The Naranjo probability scale indicates a probable relationship in both cases between the rofecoxib and blood pressure elevation.

Conclusions:

These reports suggest that rofecoxib could produce greater elevation in blood pressure in older hypertensive adults than has been previously reported. Therefore, close monitoring of blood pressure for 1–2 months after initiation of rofecoxib therapy is advisable. Further study is needed to determine the true clinical significance of these findings in older hypertensive adults.

The future of cyclooxygenase-2 inhibitors and other inhibitors of the eicosanoid signal pathway in the prevention and therapy of lung cancer

Recent advances in the understanding of the biology and molecular biology of lung cancer has provided targets for novel therapeutic and chemoprevention strategies. The eicosanoid/prostaglandin signal pathway is involved in the metabolism of membrane phospholipids to end products that are involved in apoptosis, proliferation, differentiation, and angiogenesis. Abnormalities in this pathway occur frequently in lung cancer, including the overexpression of cytoplasmic phospholipase A2, cyclooxygenase-2 (COX-2), prostaglandin E (PGE) synthase, PGE2, 5-lipoxygenase (LOX), 8-LOX, and 12-LOX. Increased levels of PGE2, 5-LOX, 8-LOX, and 12-LOX promote tumor proliferation and angiogenesis and inhibit apoptosis. On the other hand, levels of proapoptotic, antiangiogenic, and antiproliferative products are frequently decreased in lung cancer due to decreased levels of enzymes such as prostacyclin synthase. These abnormalities provide a rationale for the use of inhibitors of overexpressed enzymes or replacement of anticarcinogenic end products, and such agents have been studied in preclinical and clinical trials.

Valdecoxib: a review

BACKGROUND

Traditional nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac, ibuprofen, naproxen, and related agents are nonselective inhibitors of both cyclooxygenase-1 (COX-1) and COX-2, which catalyze prostaglandin synthesis. This inhibition accounts not only for the analgesic, anti-inflammatory, and antipyretic effects of these agents, but also for side effects such as gastric mucosal damage and renal toxicity. Substantial evidence suggests that sparing COX-1 is advantageous for gastric safety.

OBJECTIVE

This article reviews available information on the new COX-2-selective inhibitor valdecoxib, including its clinical pharmacology, pharmacokinetics, adverse effects, potential drug interactions, and contraindications and warnings. Results of clinical trials of efficacy and tolerability are summarized.

METHODS

Articles for inclusion in this review were identified through searches of PubMed and MEDLINE (1966-December 2002) and International Pharmaceutical Abstracts (1970-December 2002). Search terms included valdecoxib, Bextra, COX-2-selective inhibitors, coxibs, and selective cyclooxygenase inhibitors. The reference lists of identified articles were reviewed for additional publications. Product information was also obtained from the manufacturer of valdecoxib.

RESULTS

Fourteen clinical studies involving > 4000 patients have been conducted. Valdecoxib was significantly more effective than placebo in the treatment of adult rheumatoid arthritis, osteoarthritis, pain associated with primary dysmenorrhea, and postoperative pain. Valdecoxib was comparable to naproxen for the treatment of rheumatoid arthritis in 1 study and equivalent to naproxen for the treatment of osteoarthritis in other studies. Three studies found valdecoxib comparable to naproxen sodium for the relief of moderate to severe pain due to primary dysmenorrhea, and others found valdecoxib comparable to oxycodone plus acetaminophen and significantly more effective than rofecoxib for the relief of pain associated with dental surgery (P < 0.05). Four safety studies and 2 reviews of clinical trials documented lower rates of endoscopic gastroduodenal ulcer formation with valdecoxib compared with ibuprofen, naproxen, and diclofenac (P < 0.001 to P < 0.05). Valdecoxib did not inhibit platelet function (bleeding time and platelet aggregation) in healthy adults or in the elderly. Due to the risk of potentially serious skin and allergic reactions, patients who are allergic to sulfa-containing drugs should not take valdecoxib. The drug should be discontinued immediately if rash develops.

CONCLUSIONS

In clinical trials, valdecoxib was effective for the treatment of osteoarthritis, rheumatoid arthritis, and moderate to severe pain associated with primary dysmenorrhea. As with the other COX-2-selective inhibitors (celecoxib and rofecoxib), valdecoxib appears to produce less gastrointestinal toxicity than conventional nonselective NSAIDs, although some of the relevant clinical studies have been published only as abstracts. Use of valdecoxib should be reserved for patients at risk for NSAID-induced gastrointestinal problems.

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.

Cyclosporine A suppresses cyclooxygenase-2 expression in the rat kidney

On the basis of recent evidence that the cyclooxygenase-2 (COX-2) gene promoter contains functional binding sites for the nuclear factor of activated T cells (NFAT) and that COX-2 is expressed in a regulated fashion in the kidney, this study aimed to assess the effect of immunosuppressants on COX-2 expression in the kidney. Therefore, Wistar-Kyoto rats were treated with cyclosporine A (CsA; 15 mg/kg per day) or tacrolimus (5 mg/kg per day) for 7 d each. Both drugs markedly lowered COX-2 expression while COX-1 expression remained unaltered. Furthermore, CsA blunted the increase of renocortical COX-2 expression in response to low salt intake or a combination of low-salt diet with the ACE inhibitor ramipril (10 mg/kg per day), which strongly stimulates renocortical COX-2 expression. At the same time, calcineurin inhibitors moderately enhanced basal as well as stimulated renin secretion and renin gene expression. These findings suggest that inhibition of calcineurin could be a crucial determinant for the regulated expression of COX-2 in the kidney. Inhibition of COX-2 expression may therefore at least in part account for the well-known adverse effects of immunosuppressants in the kidney. Moreover, our data suggest that the stimulation of the renin system by low salt and by ACE inhibitors is not essentially mediated by COX-2 activity.

Renal failure associated with the use of celecoxib and rofecoxib

OBJECTIVE

Celecoxib and rofecoxib are two relatively new nonsteroidal anti-inflammatory drugs (NSAIDs) that selectively inhibit the cyclo-oxygenase-2 (COX-2) isoenzyme at therapeutic concentrations. The nephrotoxic potential of selective COX-2 inhibitors has not been clearly established. This study was conducted in order to understand the association between acute renal failure and the two COX-2 inhibitors celecoxib and rofecoxib.

METHODS

A search was performed in the US Food and Drug Administration's (FDA) Adverse Event Reporting System (AERS) to identify cases of renal failure submitted to the FDA. A MEDLINE search of the English language literature was also performed to identify published cases of renal failure associated with celecoxib and rofecoxib.

RESULTS

One hundred twenty-two and 142 domestic US cases of celecoxib and rofecoxib-associated renal failure, respectively, were identified in the AERS database. The literature search identified 19 cases of acute renal impairment in association with celecoxib and rofecoxib. In addition, drug regulatory authorities in the UK, Canada, and Australia have received about 50 reports of renal failure with celecoxib and rofecoxib. Descriptive statistics of the AERS cases have been summarised in this report.

CONCLUSIONS

Data from AERS and published case reports suggest that use of both these drugs is associated with renal effects similar to that of conventional nonselective NSAIDs. Physicians should be aware that serious or life-threatening renal failure has been reported in patients with normal or impaired renal function after short-term therapy with celecoxib and rofecoxib. Patients at greatest risk for renal injury are those with pre-existing renal impairment, heart failure, liver dysfunction, those taking diuretics and/or ACE inhibitors, and the elderly. Kidney function should be monitored closely for any signs of potential renal injuries soon after initiating treatment with these agents, especially in high-risk populations. In addition, healthcare practitioners should adequately warn patients of the signs and symptoms of serious renal toxicity, and of the need for them to see their physician promptly if they occur. Celecoxib and rofecoxib are not recommended for use in patients with advanced renal disease.

Contribution of prostaglandin D2 synthase to progression of renal failure and dialysis dementia

This article reviews the possible role of prostaglandin D(2) synthase (PGD(2)S) in the progression of chronic renal failure and dialysis dementia. Such a proposal is based on our observation that PGD(2)S significantly increases the rate of apoptosis in cultured pig kidney proximal tubule LLC-PK1 and rat neuronal PC12 cells. Apoptosis was caspase mediated and inhibitable by PGE(1), PGE(2), PGF(2alpha), platelet-derived growth factor (PDGF), and by PGD(2)S inhibitors, selenium and anti-PGD(2)S antibody. Apoptosis was restored by the addition of downstream metabolic products, PGD(2) and 15 deoxy PG triangle up (12,14)J(2). The proposal that PGD(2)S contributes to progression of renal failure and dialysis dementia is based on: (1) the progressive creatinine-like increase in PGD(2)S levels in blood as renal function decreases, increased renal cyclooxygenase (COX) 2 in chronic renal failure, and reported increase in apoptosis noted in the remnant kidney model, and (2) a 35- to 150-fold increase in blood levels of PGD(2)S in dialysis patients. Both conditions appear to favor shifting the PG metabolic pathway to downstream apoptotic metabolites, PGD(2) and 15 deoxy PG triangle up (12,14)J(2). The diverse role that PGs, growth factors, and COX play in progression of chronic renal failure, their interactions with PGD(2)S, and the status of COX inhibitors in retarding the progression of renal failure are reviewed. In addition, the need for a more systematic longitudinal assessment of dementia in dialysis patients by standardized neuropsychologic testing, testing blood levels and glycosylated isoforms of PGD(2)S, and the effect of COX inhibition and erythropoietin administration on dialysis dementia are discussed.

Cardiovascular hazard of selective COX-2 inhibitors: myth or reality?

Since 1998, two selective inhibitors of COX-2 have been approved in many countries for the treatment of rheumatoid arthritis, osteoarthritis and acute pain. These new drugs have a significantly reduced gastrointestinal toxicity when compared with non-selective COX inhibitors. However, the results of two large clinical trials conducted in patients with osteoarthritis and rheumatoid arthritis have recently raised some concerns regarding the cardiovascular safety of these new drugs. The purpose of this paper is to review the potential mechanisms whereby selective COX-2 inhibitors could increase the cardiovascular risk of patients and to analyse the data indicating that this clinical risk indeed exists. The authors' analysis shows that even though there are pathophysiological mechanisms which could explain why selective COX-2 inhibition might increase the cardiovascular risk in patients, the actual level of evidence demonstrating that the risk is indeed increased is weak. Because of the importance of the issue, additional studies must be conducted with this class of agents. Meanwhile, it is crucial to emphasise that neither selective COX-2 inhibitors nor conventional NSAIDs replace aspirin in patients with a high cardiovascular risk.