Systemic biosynthesis of prostacyclin by cyclooxygenase (COX)-2: the human pharmacology of a selective inhibitor of COX-2

Prostaglandin terminal synthases as novel therapeutic targets

Non-steroidal anti-inflammatory drugs (NSAIDs) exert their anti-inflammatory and anti-tumor effects by reducing prostaglandin (PG) production via the inhibition of cyclooxygenase (COX). However, the gastrointestinal, renal and cardiovascular side effects associated with the pharmacological inhibition of the COX enzymes have focused renewed attention onto other potential targets for NSAIDs. PGH₂, a COX metabolite, is converted to each PG species by species-specific PG terminal synthases. Because of their potential for more selective modulation of PG production, PG terminal synthases are now being investigated as a novel target for NSAIDs. In this review, I summarize the current understanding of PG terminal synthases, with a focus on microsomal PGE synthase-1 (mPGES-1) and PGI synthase (PGIS). mPGES-1 and PGIS cooperatively exacerbate inflammatory reactions but have opposing effects on carcinogenesis. mPGES-1 and PGIS are expected to be attractive alternatives to COX as therapeutic targets for several diseases, including inflammatory diseases and cancer.

Atherosclerosis revisited from a clinical perspective: still an inflammatory disease?

Compelling experimental results have substantiated the immune-driven inflammatory nature of atherosclerosis. Most of the scientific advances over the past decades have been achieved by relying on transgenic animal models that have been employed with increasing levels of sophistication. However, recent failures in translating various anti-inflammatory therapeutic strategies for use in humans might raise some skepticism with regards to an inflammatory causality underlying human atherosclerosis. By applying a dialectical approach, this Perspective aims to challenge and deduce the nature of atherosclerosis by reviewing results exclusively derived from human studies and recent clinical trials, as "things may not always be, what they appear".

Celecoxib increases lung cancer cell lysis by lymphokine-activated killer cells via upregulation of ICAM-1

The antitumorigenic mechanism of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib is still a matter of debate. Using lung cancer cell lines (A549, H460) and metastatic cells derived from a lung cancer patient, the present study investigates the impact of celecoxib on the expression of intercellular adhesion molecule 1 (ICAM-1) and cancer cell lysis by lymphokine-activated killer (LAK) cells. Celecoxib, but not other structurally related selective COX-2 inhibitors (i.e., etoricoxib, rofecoxib, valdecoxib), was found to cause a substantial upregulation of ICAM-1 protein levels. Likewise, ICAM-1 mRNA expression was increased by celecoxib. Celecoxib enhanced the susceptibility of cancer cells to be lysed by LAK cells with the respective effect being reversed by a neutralizing ICAM-1 antibody. In addition, enhanced killing of celecoxib-treated cancer cells was reversed by preincubation of LAK cells with an antibody to lymphocyte function associated antigen 1 (LFA-1), suggesting intercellular ICAM-1/LFA-1 crosslink as crucial event within this process. Finally, celecoxib elicited no significant increase of LAK cell-mediated lysis of non-tumor bronchial epithelial cells, BEAS-2B, associated with a far less ICAM-1 induction as compared to cancer cells. Altogether, our data demonstrate celecoxib-induced upregulation of ICAM-1 on lung cancer cells to be responsible for intercellular ICAM-1/LFA-1 crosslink that confers increased cancer cell lysis by LAK cells. These findings provide proof for a novel antitumorigenic mechanism of celecoxib.

Current controversies in the use of aspirin and ticagrelor for the treatment of thrombotic events

INTRODUCTION

A P2Y₁₂ inhibitor plus aspirin is the most widely used antiplatelet strategy to prevent adverse outcomes in the setting of atherothrombotic vascular disease. Areas covered: A paucity of robust evidence for an optimal dose, gastrointestinal toxicity, ineffectiveness in high-risk patients and interactions with other antiplatelet agents, are major controversies associated with aspirin therapy. Ticagrelor is a reversibly binding oral P2Y₁₂ receptor blocker that mediates potent inhibition of adenosine diphosphate-induced platelet function. It is more effective than clopidogrel in preventing thrombotic events in acute coronary syndrome patients. The absence of a beneficial effect for ticagrelor versus clopidogrel in ACS observed in the North American subgroup of the PLATelet inhibition and patient Outcomes (PLATO) trial has been attributed to a higher concomitant aspirin dose. Expert commentary: Ongoing studies are now investigating the plausibility of removing aspirin therapy in the setting of potent P2Y₁₂ receptor blockade via ticagrelor monotherapy or replacing aspirin with an oral anticoagulant.

Cardiovascular Effects of Nonsteroidal Anti-inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) include aspirin, other traditional NSAIDs, and coxibs. Evidence obtained during the past 10 years has focused attention on the cardiovascular hazard associated with coxibs and some traditional NSAIDs. The large randomized trials of prolonged coxib treatment added importantly to information provided by epidemiological studies that had previously associated regular use of NSAIDs with increased blood pressure and enhanced risk of congestive heart failure, and identified an increased risk of myocardial infarction as a class effect of cyclooxygenase-2 inhibitors. The aim of this article is to review the cardiovascular effects of aspirin, other traditional NSAIDs, and coxibs, to discuss the mechanisms underlying these effects, and to provide a clinical perspective on the cardiovascular hazard associated with their use.

Cardiovascular effects of cyclooxygenase-2 inhibitors: a mechanistic and clinical perspective

LINKED ARTICLES

This article is part of a joint Themed section with the British Journal of Pharmacology on Targeting Inflammation to Reduce Cardiovascular Disease Risk: a Realistic Clinical Prospect? The rest of the Themed section will appear in a future issue of BJP and will be available at http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1476-5381 Prostaglandin (PG) H synthase 2 [also referred to colloquially as cyclooxygenase (COX) 2] represents a key enzyme in arachidonic acid metabolism in health and disease. It is both constitutively expressed in several human tissues (e.g. kidney and brain) and induced in various cell types (including monocytes/macrophages, vascular endothelial cells and colorectal cancer cells) in response to inflammatory cytokines, laminar shear stress and growth factors. Products of COX-2 activity (e.g. PGE2 and prostacyclin) are involved in diverse physiological and pathophysiological processes, including renal haemodynamics and the control of blood pressure, endothelial thromboresistance, pain and inflammation, and colorectal tumorigenesis. Therefore, it is not surprising that COX-2 inhibitors display multifaceted clinical effects, ranging from reduced pain and inflammation to increased blood pressure, an increased risk of atherothrombotic events and a decreased risk of colorectal cancer. The aim of the present article was to review the cardiovascular effects of COX-2 inhibitors [traditional nonsteroidal anti-inflammatory drugs (tNSAIDs) and coxibs alike], with a focus on the mechanisms contributing to the clinical readouts of COX-2 inhibition.

Prostaglandin I2 upregulates the expression of anterior pharynx-defective-1α and anterior pharynx-defective-1β in amyloid precursor protein/presenilin 1 transgenic mice

Cyclooxygenase‐2 (COX‐2) has been recently identified to be involved in the pathogenesis of Alzheimer's disease (AD). Yet, the role of an important COX‐2 metabolic product, prostaglandin (PG) I₂, in the pathogenesis of AD remains unknown. Using human‐ and mouse‐derived neuronal cells as well as amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice as model systems, we elucidated the mechanism of anterior pharynx‐defective (APH)‐1α and pharynx‐defective‐1β induction. In particular, we found that PGI₂ production increased during the course of AD development. Then, PGI₂ accumulation in neuronal cells activates PKA/CREB and JNK/c‐Jun signaling pathways by phosphorylation, which results in APH‐1α/1β expression. As PGI₂ is an important metabolic by‐product of COX‐2, its suppression by NS398 treatment decreases the expression of APH‐1α/1β in neuronal cells and APP/PS1 mice. More importantly, β‐amyloid protein (Aβ) oligomers in the cerebrospinal fluid (CSF) of APP/PS1 mice are critical for stimulating the expression of APH‐1α/1β, which was blocked by NS398 incubation. Finally, the induction of APH‐1α/1β was confirmed in the brains of patients with AD. Thus, these findings not only provide novel insights into the mechanism of PGI₂‐induced AD progression but also are instrumental for improving clinical therapies to combat AD.

Evaluation of effects of various drugs on platelet functions using phorbol 12-myristate 13-acetate-induced megakaryocytic human erythroid leukemia cells

Background

The hyperfunction and activation of platelets have been strongly implicated in the development and recurrence of arterial occlusive disease, and various antiplatelet drugs are used to treat and prevent such diseases. New antiplatelet drugs and many other drugs have been developed, but some drugs may have adverse effects on platelet functions.

Objective

The aim of this study was to establish an evaluation method for evaluating the effect and adverse effect of various drugs on platelet functions.

Materials and methods

Human erythroid leukemia (HEL) cells were used after megakaryocytic differentiation with phorbol 12-myristate 13-acetate as an alternative to platelets. Drugs were evaluated by changes in intracellular Ca²⁺ concentration ([Ca²⁺]_i) mobilization in Fura2-loaded phorbol 12-myristate 13-acetate-induced HEL cells. Aspirin and cilostazol were selected as antiplatelet drugs and ibuprofen and sodium valproate as other drugs.

Results

There was a positive correlation between [Ca²⁺]_i and platelet aggregation induced by thrombin. Aspirin (5.6–560 µM) and cilostazol (5–10 µM) significantly inhibited thrombin-induced increases in [Ca²⁺]_i in a concentration-dependent manner. On the other hand, ibuprofen (8–200 µM) and sodium valproate (50–1,000 µg/mL) also significantly inhibited thrombin-induced increases in [Ca²⁺]_i in a concentration-dependent manner. Furthermore, the interaction effects of the simultaneous combined use of aspirin and ibuprofen or sodium valproate were evaluated. When the inhibitory effect of aspirin was higher than that of ibuprofen, the effect of aspirin was reduced, whereas when the inhibitory effect of aspirin was lower than that of ibuprofen, the effect of ibuprofen was reduced. The combination of aspirin and sodium valproate synergistically inhibited thrombin-induced [Ca²⁺]_i.

Conclusion

It is possible to induce HEL cells to differentiate into megakaryocytes, which are a useful model for the study of platelet functions, and the quantification of the inhibition of thrombin-induced increases in [Ca²⁺]_i is applicable to the evaluation of the effects of various drugs on platelets.

A broad-spectrum lipidomics screen of antiinflammatory drug combinations in human blood

Current methods of drug screening in human blood focus on the immediate products of the affected pathway and mostly rely on approaches that lack sensitivity and the capacity for multiplex analysis. We have developed a sensitive and selective method based on ultra-performance liquid chromatography-tandem mass spectrometry to scan the effect of drugs on the bioactive eicosanoid lipidome in vitro and ex vivo. Using small sample sizes, we can reproducibly measure a broad spectrum of eicosanoids in human blood and capture drug-induced substrate rediversion and unexpected shifts in product formation. Microsomal prostaglandin E synthase-1 (mPGES-1) is an antiinflammatory drug target alternative to COX-1/-2. Contrasting effects of targeting mPGES-1 versus COX-1/-2, due to differential substrate shifts across the lipidome, were observed and can be used to rationalize and evaluate drug combinations. Finally, the in vitro results were extrapolated to ex vivo studies by administration of the COX-2 inhibitor, celecoxib, to volunteers, illustrating how this approach can be used to integrate preclinical and clinical studies during drug development.

[The problem of cardiac safety of nonsteroidal anti-inflammatory drugs]

The paper considers an update on the mechanisms for the development of adverse reactions of nonsteroidal anti-inflammatory drugs on the cardiovascular system.

Risk of perioperative bleeding related to highly selective cyclooxygenase-2 inhibitors: A systematic review and meta-analysis

BACKGROUND

Several literatures reported that highly selective cycloxygenase-2 inhibitors (COX-2 inhibitors) had no effect on platelet function. However, some experts suggested stopping all non-steroidal anti-inflammatory drugs (NSAIDs), including COX-2 inhibitors at least five elimination half-lives prior to surgery. We, therefore, systematically summarized the risk of clinical bleeding or platelet dysfunction in healthy or surgical subjects who received COX-2 inhibitors.

METHODS

Two electronic databases, MEDLINE and EMBASE, were searched for randomized, controlled studies published during 1980-December 2015. Additionally, manual search was performed to identify potential eligible studies. Intervention was perioperative use of any available COX-2 inhibitors in current practice (celecoxib, parecoxib, or etoricoxib), compared to non-selective NSAIDs, analgesics, or placebo. Two independent reviewers selected eligible studies, extracted the data, and assessed the quality of the included studies. The primary outcome was postoperative bleeding. All analyses were performed using RevMan-5.3.

RESULTS

Of 3900 abstracts reviewed, 35 studies met the inclusion criteria. The data from 16 out of 35 studies were used in this meta-analysis, and outcomes of other 19 remaining studies were descriptively summarized. COX-2 inhibitors did not significantly increase the risk of postoperative bleeding events (relative risk or RR = 0.92; 95% confidence interval or CI: 0.63-1.33; p = 0.65), intraoperative blood loss (mL) (weighted mean difference or WMD = -4.38; 95% CI: -14.69 to 5.92; p = 0.4), postoperative blood loss (mL) (WMD = -13.89; 95% CI: -30.24 to 2.47; p = 0.10), and 24-h postoperative hemoglobin loss (g/dL) (WMD = 0.47; 95% CI: -0.14 to 1.09; p = 0.13). Platelet function analyzer closure time (second) significantly decreased with the use of COX-2 inhibitors (WMD = -22.22; 95% CI: -44.03 to -0.41; p < 0.00001). In the 19 remaining studies, COX-2 inhibitors did not significantly increase risk of bleeding in both clinical and laboratory outcomes.

CONCLUSION

Highly selective COX-2 inhibitors did not significantly increase the risk of intraoperative, postoperative bleeding, or blood loss. They also had no significant effect on platelet function. Therefore, perioperative, single dose, or short course of COX-2 inhibitors can be safely used in individuals who are undergoing surgery.

Equivalent intraperitoneal doses of ibuprofen supplemented in drinking water or in diet: a behavioral and biochemical assay using antinociceptive and thromboxane inhibitory dose-response curves in mice

Background. Ibuprofen is used chronically in different animal models of inflammation by administration in drinking water or in diet due to its short half-life. Though this practice has been used for years, ibuprofen doses were never assayed against parenteral dose–response curves. This study aims at identifying the equivalent intraperitoneal (i.p.) doses of ibuprofen, when it is administered in drinking water or in diet.

Methods. Bioassays were performed using formalin test and incisional pain model for antinociceptive efficacy and serum TXB₂ for eicosanoid inhibitory activity. The dose–response curve of i.p. administered ibuprofen was constructed for each test using 50, 75, 100 and 200 mg/kg body weight (b.w.). The dose–response curves were constructed of phase 2a of the formalin test (the most sensitive phase to COX inhibitory agents), the area under the ‘change in mechanical threshold’-time curve in the incisional pain model and serum TXB₂ levels. The assayed ibuprofen concentrations administered in drinking water were 0.2, 0.35, 0.6 mg/ml and those administered in diet were 82, 263, 375 mg/kg diet.

Results. The 3 concentrations applied in drinking water lay between 73.6 and 85.5 mg/kg b.w., i.p., in case of the formalin test; between 58.9 and 77.8 mg/kg b.w., i.p., in case of the incisional pain model; and between 71.8 and 125.8 mg/kg b.w., i.p., in case of serum TXB₂ levels. The 3 concentrations administered in diet lay between 67.6 and 83.8 mg/kg b.w., i.p., in case of the formalin test; between 52.7 and 68.6 mg/kg b.w., i.p., in case of the incisional pain model; and between 63.6 and 92.5 mg/kg b.w., i.p., in case of serum TXB₂ levels.

Discussion. The increment in pharmacological effects of different doses of continuously administered ibuprofen in drinking water or diet do not parallel those of i.p. administered ibuprofen. It is therefore difficult to assume the equivalent parenteral daily doses based on mathematical calculations.

Assessing the negative impact of phenyl alkanoic acid derivative, a frequently prescribed drug for the suppression of pain and inflammation, on the differentiation and proliferation of chondrocytes

Background

Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently prescribed to relieve pain and inflammation. These NSAIDs have also analgesic effects and can be administered via oral, injectable, and topical routes. During inflammation, a number of synovial mediators and cytokines are released which decrease the pH level of the synovial fluid. Administration of acidic NSAIDs further decreases the pH levels and hence contributes to the destruction of the cartilage. To our knowledge, no cellular-based study regarding the chondrotoxicity of phenyl alkanoic acid derivatives on NSAIDs was conducted before. Thus, the aim of this pioneering study was to examine the effect of frequently prescribed NSAIDs, a phenyl alkanoic acid derivative, flurbiprofen, on the proliferation and differentiation of human primer chondrocyte cultures in vitro.

Methods

Primer chondrocyte cultures were prepared from osteochondral tissue obtained during surgery for gonarthrosis. Samples not exposed to the pharmacological agent were used as the control group. The samples were treated with 1, 10, 100, 250, 500, or 1000 μM of the agent for 24, 48, and 72 h. The cell viability, toxicity, and proliferation were assessed with MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) analysis and prechondrocytic precursor stage-specific embryonic antigen-1 (SSEA-1) expression using a commercial ELISA kit spectrophotometrically. The surface morphology of the samples in each group was compared using an inverted light microscope and an environmental scanning electron microscope (ESEM). An analysis of variance was used to compare between-group differences. Tukey’s honest significant difference (HSD) method (95 % confidence interval) was used to evaluate the differences and significance in averages. The alpha significance value was considered <0.01.

Results

Statistically significant cytotoxicity was observed in the treatment groups. NSAID had a significant negative effect on the proliferation and differentiation of chondrocytes as compared to the control group (p < 0.01).

Conclusion

Before administering phenyl alkanoic acid derivatives in the clinical setting, their role in suppressing the proliferation and differentiation of chondrocytes should be taken into account. Thus, caution should be given when prescribing these drugs.

Relationship Between Cyclooxygenase-2 Inhibition and Thrombogenesis

Recently there has been considerable interest in the role of cyclooxygenase-2 (COX-2) in thrombosis and myocardial infarction. A large number of clinical and basic studies have focused on whether COX-2 inhibitors can induce a prothrombotic disorder and increase the risk of cardiovascular thrombosis. This article reviews (1) the roles of COX-2 in the metabolism of prostaglandins; (2) the influence of COX-2 inhibition in the platelet aggregation and the antithrombotic function of vascular endothelium; (3) the roles of COX-2 inhibition in atherothrombosis; and (4) clinical trials that examine COX-2 inhibition in relationship to the risk of myocardial infarction. Based on the published data, this review suggests that COX-2 plays varying and sometimes conflicting roles in thrombogenesis, in prostaglandins' metabolism of endothelium in healthy or dysfunctional conditions, and in atherothrombosis. Future investigations under different pathologic conditions are needed to fully understand the net effect of COX-2 inhibition on thrombogenesis. The roles of COX-2 in the pathophysiologic process of cardiovascular thrombosis are diverse and controversial, and need to be further studied to guide clinical practice.

The endothelial cyclooxygenase pathway: Insights from mouse arteries

To date, cyclooxygenase-2 (COX-2) is commonly believed to be the major mediator of endothelial prostacyclin (prostaglandin I2; PGI2) synthesis that balances the effect of thromboxane (Tx) A2 synthesis mediated by the other COX isoform, COX-1 in platelets. Accordingly, selective inhibition of COX-2 is considered to cause vasoconstriction, platelet aggregation, and hence increase the incidence of cardiovascular events. This idea has been claimed to be substantiated by experiments on mouse models, some of which are deficient in one of the two COX isoforms. However, results from our studies and those of others using similar mouse models suggest that COX-1 is the major functional isoform in vascular endothelium. Also, although PGI2 is recognized as a potent vasodilator, in some arteries endothelial COX activation causes vasoconstrictor response. This has again been recognized by studies, especially those performed on mouse arteries, to result largely from endothelial PGI2 synthesis. Therefore, evidence that supports a role for COX-1 as the major mediator of PGI2 synthesis in mouse vascular endothelium, reasons for the inconsistency, and results that elucidate underlying mechanisms for divergent vasomotor reactions to endothelial COX activation will be discussed in this review. In addition, we address the possible pathological implications and limitations of findings obtained from studies performed on mouse arteries.

Antinociceptive Effects of Prim-O-Glucosylcimifugin in Inflammatory Nociception via Reducing Spinal COX-2

We measured anti-nociceptive activity of prim-o-glucosylcimifugin (POG), a molecule from Saposhnikovia divaricate (Turcz) Schischk. Anti-nociceptive or anti-inflammatory effects of POG on a formalin-induced tonic nociceptive response and a complete Freund’s adjuvant (CFA) inoculation-induced rat arthritis pain model were studied. Single subcutaneous injections of POG produced potent anti-nociception in both models that was comparable to indomethacin analgesia. Anti-nociceptive activity of POG was dose-dependent, maximally reducing pain 56.6% with an ED₅₀ of 1.6 mg. Rats given POG over time did not develop tolerance. POG also time-dependently reduced serum TNFα, IL-1β and IL-6 in arthritic rats and both POG and indomethacin reduced spinal prostaglandin E2 (PGE₂). Like indomethacin which inhibits cyclooxygenase-2 (COX-2) activity, POG dose-dependently decreased spinal COX-2 content in arthritic rats. Additionally, POG, and its metabolite cimifugin, downregulated COX-2 expression in vitro. Thus, POG produced potent anti-nociception by downregulating spinal COX-2 expression.

Fabrication and evaluation of lipid nanoparticulates for ocular delivery of a COX-2 inhibitor

CONTEXT

The unique physiological limitations of the eye have been assigned as reason of low bioavailability by conventional drug delivery systems. There is need of such drug carriers, which ensure improved bioavailability as well as patient compliance upon instillation into the eye.

OBJECTIVE

The present investigation deals with development of solid lipid nanoparticles (SLNs) containing celecoxib (CXB) for treatment of ophthalmic inflammations.

MATERIALS AND METHODS

The SLNs were formulated by melt-emulsion sonication and low temperature-solidification process and evaluated for particle size, surface morphology, physicochemical properties, percentage drug incorporation efficiency, in vitro drug release, in vitro trans-corneal permeation, in vivo efficacy in ocular inflammation, stability study and gamma scintigraphy study to assess the residence of solid lipid nanoparticles over ocular surfaces.

RESULTS

The SLNs were spherical and the optimized formulation had particle size of 198.77 ± 7.5 nm, which is quite suitable for ocular applications. The maximum entrapment efficiency of 92.46 ± 0.07% was achieved for formulation SLN 20. The permeation across the cornea was also significantly better than aqueous suspension (8.21 ± 0.67 versus 4.61 ± 0.71) at p < 0.05.

DISCUSSION AND CONCLUSION

The SLN formulations demonstrated improved performance of entrapped CXB while mitigating the key parameters of ocular inflammation in rabbits. The particulate formulations have exhibited prolonged retention over ocular surfaces as evident from results of gamma scintigraphy using ^99mTc labeled SLNs.

Inhibition of prostacyclin and thromboxane biosynthesis in healthy volunteers by single and multiple doses of acetaminophen and indomethacin

This double-blind, randomized crossover study assessed the effect of acetaminophen (1000 mg every 8 hours) versus indomethacin (50 mg every 8 hours) versus placebo on cyclooxygenase enzymes (COX-1 and COX-2). Urinary excretion of 2,3-dinor-6-keto-PGF1α, (prostacyclin metabolite, PGI-M; COX-2 inhibition) and 11-dehydro thromboxane B2 (thromboxane metabolite, Tx-M; COX-1 inhibition) were measured after 1 dose and 5 days of dosing. Peak inhibition of urinary metabolite excretion across 8 hours following dosing was the primary end point. Mean PGI-M excretion was 33.7%, 55.9%, and 64.6% on day 1 and 49.4%, 65.1%, and 80.3% on day 5 (placebo, acetaminophen, and indomethacin, respectively). Acetaminophen and indomethacin inhibited PGI-M excretion following single and multiple doses (P = .004 vs placebo). PGI-M excretion inhibition after 1 dose was similar for indomethacin and acetaminophen, but significantly greater with indomethacin after multiple doses (P = .006). Mean Tx-M excretion was 16.2%, 45.2%, and 86.6% on day 1 and 46.2%, 58.4%, and 92.6% on day 5 (placebo, acetaminophen, and indomethacin, respectively). Tx-M excretion inhibition following 1 dose was reduced by acetaminophen (P ≤ .003). Indomethacin reduced Tx-M excretion significantly more than acetaminophen and placebo after single and multiple doses (P ≤ .001). Acetaminophen and indomethacin inhibited COX-1 and COX-2 following a single dose, but acetaminophen was a less potent COX-1 inhibitor than indomethacin.

An overview of treatment approaches for chronic pain management

Pain which persists after healing is expected to have taken place, or which exists in the absence of tissue damage, is termed chronic pain. By definition chronic pain cannot be treated and cured in the conventional biomedical sense; rather, the patient who is suffering from the pain must be given the tools with which their long-term pain can be managed to an acceptable level. This article will provide an overview of treatment approaches available for the management of persistent non-malignant pain. As well as attempting to provide relief from the physical aspects of pain through the judicious use of analgesics, interventions, stimulations, and irritations, it is important to pay equal attention to the psychosocial complaints which almost always accompany long-term pain. The pain clinic offers a biopsychosocial approach to treatment with the multidisciplinary pain management programme; encouraging patients to take control of their pain problem and lead a fulfilling life in spite of the pain.

Bidirectional interactions between indomethacin and the murine intestinal microbiota

The vertebrate gut microbiota have been implicated in the metabolism of xenobiotic compounds, motivating studies of microbe-driven metabolism of clinically important drugs. Here, we studied interactions between the microbiota and indomethacin, a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenases (COX) -1 and -2. Indomethacin was tested in both acute and chronic exposure models in mice at clinically relevant doses, which suppressed production of COX-1- and COX-2-derived prostaglandins and caused small intestinal (SI) damage. Deep sequencing analysis showed that indomethacin exposure was associated with alterations in the structure of the intestinal microbiota in both dosing models. Perturbation of the intestinal microbiome by antibiotic treatment altered indomethacin pharmacokinetics and pharmacodynamics, which is probably the result of reduced bacterial β-glucuronidase activity. Humans show considerable inter-individual differences in their microbiota and their responses to indomethacin - thus, the drug-microbe interactions described here provide candidate mediators of individualized drug responses.

COX inhibitors: a patent review (2011 - 2014)

INTRODUCTION

The COX enzymes play a central role in the biosynthetic pathway of important biological mediators called prostanoids. Differences in regulation of gene expression, stability of transcripts and proteins determine the different biological functions of COX-1 and COX-2. While the COX-1 gene has been considered to be a 'housekeeping' gene expressed in many tissues and cells, COX-2 gene is upregulated during inflammation, hypoxia and in many cancers.

AREAS COVERED

The first part of this review provides a survey of the development of both modified traditional NSAIDs (tNSAIDs) and COX inhibitors (coxibs) with reduced side effects for the treatment of inflammation and cancer. The second part deals with patents reporting several dual inhibitors characterized by the conjugation of a COX-inhibitor scaffold to a molecule able to modulate a different target. Finally, two patents on novel COX inhibitor scaffolds are reported.

EXPERT OPINION

The most interesting branch of research concerns the conjugation of a COX-inhibitor scaffold to a molecule able to modulate a different target, in order to either enhance anti-inflammatory activity or to act as a dual inhibitor. Among the described compounds, selenium-containing coxibs inhibiting COX-2 and Akt, in addition to the multi-target biphenyl derivatives as dual inhibitors of COX and fatty acid amide hydrolase, are the most promising ones.

Discovery of substituted-2,4-dimethyl-(naphthalene-4-carbonyl)amino-benzoic acid as potent and selective EP4 antagonists

A novel series of EP4 antagonists, based on a quinoline scaffold, has been discovered. Medicinal chemistry efforts to optimize the potency of the initial hit are described. A highly potent compound in a clinically relevant human whole blood assay was identified. Selectivity and pharmacokinetic profiles of this compound are discussed.

Cyclo-oxygenase-2 inhibition and endothelium-dependent vasodilation in younger vs. older healthy adults

AIM

A major feature of endothelial dysfunction is reduced endothelium-dependent vasodilation, which in ageing may be due to decreased production of endothelial prostacyclin, or nitric oxide (NO), or both.

METHOD

We tested this hypothesis in 12 younger (age 18-38 years, six women) and 12 older healthy adults (age 55-73 years, six post-menopausal women). Endothelium-dependent vasodilation was assessed by the forearm vascular conductance (FVC) response to intra-arterial acetylcholine (ACh) (0.5, 1.0, 2.0, 4.0 μg dl(-1) forearm tissue min(-1) ) before and 90 min after inhibition of the enzyme cyclo-oxygenase-2 (COX-2) with oral celecoxib (400 mg), followed by the addition of endothelial NO synthase inhibition with intra-arterial N(G) -monomethyl-l arginine acetate (L-NMMA).

RESULTS

Ageing was associated with a significantly reduced FVC response to ACh (P = 0.009, age-by-dose interaction; highest dose FVC ± SEM in ageing: 11.2 ± 1.4 vs. younger: 17.7 ± 2.4 units, P = 0.02). Celecoxib did not reduce resting FVC or the responses to ACh in any group. L-NMMA significantly reduced resting FVC and the responses to ACh in all groups, and absolute FVC values following L-NMMA were similar between groups.

CONCLUSION

In healthy normotensive younger and older adults, there is minimal contribution of prostacyclin to ACh-mediated vasodilation, yet the NO component of vasodilation is reduced with ageing. In the clinical context, these findings suggest that acute administration of medications that inhibit prostacyclin (i.e. COX-2 inhibitors) evoke modest vascular consequences in healthy persons. Additional studies are necessary to test whether chronic use of COX-2 medications reduces endothelium dependent vasodilation in older persons with or without cardiovascular risk factors.

An anti-inflammatory role for C/EBPδ in human brain pericytes

Neuroinflammation contributes to the pathogenesis of several neurological disorders and pericytes are implicated in brain inflammatory processes. Cellular inflammatory responses are orchestrated by transcription factors but information on transcriptional control in pericytes is lacking. Because the transcription factor CCAAT/enhancer binding protein delta (C/EBPδ) is induced in a number of inflammatory brain disorders, we sought to investigate its role in regulating pericyte immune responses. Our results reveal that C/EBPδ is induced in a concentration- and time-dependent fashion in human brain pericytes by interleukin-1β (IL-1β). To investigate the function of the induced C/EBPδ in pericytes we used siRNA to knockdown IL-1β-induced C/EBPδ expression. C/EBPδ knockdown enhanced IL-1β-induced production of intracellular adhesion molecule-1 (ICAM-1), interleukin-8, monocyte chemoattractant protein-1 (MCP-1) and IL-1β, whilst attenuating cyclooxygenase-2 and superoxide dismutase-2 gene expression. Altered ICAM-1 and MCP-1 protein expression were confirmed by cytometric bead array and immunocytochemistry. Our results show that knock-down of C/EBPδ expression in pericytes following immune stimulation increased chemokine and adhesion molecule expression, thus modifying the human brain pericyte inflammatory response. The induction of C/EBPδ following immune stimulation may act to limit infiltration of peripheral immune cells, thereby preventing further inflammatory responses in the brain.

Oxytocin evokes a pulsatile PGE2 release from ileum mucosa and is required for repair of intestinal epithelium after injury

We measured the short-circuit current (I_sc) in rat ileum mucosa to identify the effect of oxytocin (OT) on mucosal secretion in small intestine. We identified a COX-2-derived pulsatile PGE2 release triggered by OT in rat ileum mucosa. OT receptors (OTR) are expressed in intestine crypt epithelial cells. Notably, OT evoked a dynamic change of [Ca²⁺]_i in ileum crypts, which was responsible for this pulsatile release of PGE2. OT ameliorated 5-FU-, radiation- or DSS- induced injury in vivo, including the improvement of weight loss, reduced villus height and impaired survival of crypt transit-amplifying cells as well as crypt. Moreover, these protective effects of OT against intestinal injury were eliminated by coadministration of a selective inhibitor of PGE2, AH6809. Our findings strongly suggest that OT, a novel and important regulator of intestine mucosa barrier, is required for repair of intestinal epithelium after injury. Considering that OT is an FDA-approved drug, this work reveals a potential novel and safe way to combat or prevent chemo-radiotherapy induced intestine injury or to treat IBD.

Esterase-activated release of naproxen from supramolecular nanofibres

Nanofibre forming peptide amphiphiles were conjugated to naproxen through an esterase-sensitive linker. The amount of naproxen released, in the presence of enzymes, was influenced by the linker conjugating the drug to the supramolecular assembly. In vitro studies showed the anti-inflammatory activity of the released drug was maintained.

Loss of Nrf2 in bone marrow-derived macrophages impairs antigen-driven CD8(+) T cell function by limiting GSH and Cys availability

NF-E2-related factor 2 (Nrf2), known to protect against reactive oxygen species, has recently been reported to resolve acute inflammatory responses in activated macrophages. Consequently, disruption of Nrf2 promotes a proinflammatory macrophage phenotype. In the current study, we addressed the impact of this macrophage phenotype on CD8(+) T cell activation by using an antigen-driven coculture model consisting of Nrf2(-/-) and Nrf2(+/+) bone marrow-derived macrophages (BMDMΦ) and transgenic OT-1 CD8(+) T cells. OT-1 CD8(+) T cells encode a T cell receptor that specifically recognizes MHC class I-presented ovalbumin OVA(257-264) peptide, thereby causing a downstream T cell activation. Interestingly, coculture of OVA(257-264)-pulsed Nrf2(-/-) BMDMΦ with transgenic OT-1 CD8(+) T cells attenuated CD8(+) T cell activation, proliferation, and cytotoxic function. Since the provision of low-molecular-weight thiols such as glutathione (GSH) or cysteine (Cys) by macrophages limits antigen-driven CD8(+) T cell activation, we quantified the amounts of intracellular and extracellular GSH and Cys in both cocultures. Indeed, GSH levels were strongly decreased in Nrf2(-/-) cocultures compared to wild-type counterparts. Supplementation of thiols in Nrf2(-/-) cocultures via addition of glutathione ester, N-acetylcysteine, β-mercaptoethanol, or cysteine itself restored T cell proliferation as well as cytotoxicity by increasing intracellular GSH. Mechanistically, we identified two potential Nrf2-regulated genes involved in thiol synthesis in BMDMΦ: the cystine transporter subunit xCT and the modulatory subunit of the GSH-synthesizing enzyme γ-GCS (GCLM). Pharmacological inhibition of γ-GCS-dependent GSH synthesis as well as knockdown of the cystine antiporter xCT in Nrf2(+/+) BMDMΦ mimicked the effect of Nrf2(-/-) BMDMΦ on CD8(+) T cell function. Our findings demonstrate that reduced levels of GCLM as well as xCT in Nrf2(-/-) BMDMΦ limit GSH availability, thereby inhibiting antigen-induced CD8(+) T cell function.

Hormones in Dairy Foods and Their Impact on Public Health - A Narrative Review Article

BACKGROUND

The presence of hormones in milk and dairy foods was discussed decades ago but rather more concerns attended to that with respect to finding hormones as biomarkers in milk for diseases and pregnancy diagnosis. Moreover, considerable amount of studies demonstrated that existing of hormones in humans and animals milk are essential for infants growing and immunity. During the last couple of years, increasing body of evidence are indicating another property of hormones in dairy products as possible impact on human health including the role of some estrogens and insulin-like growth factor-1 in initiation and provoking of breast, prostate and endometrial tumours.

METHODS

Data was gathered from the published articles in database such as MEDLINE, science direct, Google scholar and web of science. We put no limitation on date of published date. Moreover, our own published and conducted methods and results also are presented. In this review we concentrated on several aspects of presence of hormones in dairy foods with especial emphasize on cow's milk as a major source of consuming milk for humans especially for children.

RESULTS

The collected data from other researchers and our own data are indicating that the presence of steroid hormones in dairy products could be counted as an important risk factor for various cancers in humans.

CONCLUSION

Our gathered data in this review paper may suggest more sophisticate analytical detection methods for oestrogens determination and also could be considered as a remarkable concern for consumers, producers and public health authorities.

Elevation of cardiovascular risk by non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently used medications. NSAIDs profoundly modify prostaglandin homeostasis through inhibition of the enzyme, cyclooxygenase (COX), especially COX-2. COX-2 inhibition is associated with adverse cardiovascular outcomes as demonstrated by recent trials using this type of drug. This review explores the latest available data, including recent, randomized, clinical trials, controversies, and pathophysiology of the adverse effects of COX-inhibition.

Circulating Prostaglandin Biosynthesis in Colorectal Cancer and Potential Clinical Significance

BACKGROUND

Colorectal cancer (CRC) represents the third leading cause of cancer-related death in the United States. Lack of reliable biomarkers remains a critical issue for early detection of CRC. In this study, we investigated the potential predictive values of circulating prostaglandin (PG) biosynthesis in CRC risk.

METHODS

Profiles of circulating PG biosynthesis and platelet counts were determined in healthy subjects (n = 16), familial adenomatous polyposis (FAP) patients who were classified as regular aspirin users (n = 14) or nonusers (n = 24), and CRC patients with (n = 18) or without FAP history (n = 20). Immunohistochemistry staining was performed on biopsy samples.

RESULTS

Analysis of circulating PG biosynthesis unexpectedly revealed that CRC progression is accompanied by a pronounced elevation of circulating thromboxane A2 (TXA₂) levels. When a circulating TXA₂ level of 1000 pg/mL was selected as a practical cutoff point, 95% of CRC patients were successfully identified. Further study suggested that the TXA₂ pathway is constitutively activated during colorectal tumorigenesis and required for anchorage-independent growth of colon cancer cells.

CONCLUSIONS

This study established the importance of the TXA₂ pathway in CRC pathophysiology, and laid the groundwork for introducing a TXA₂-targeting strategy to CRC prevention, early detection and management.

Prostacyclin regulates bone growth via the Epac/Rap1 pathway

Prostaglandins, particularly PGE2, are important to adult bone and joint health, but how prostaglandins act on growth plate cartilage to affect bone growth is unclear. We show that growth plate cartilage is distinct from articular cartilage with respect to cyclooxygenase (COX)-2 mRNA expression; although articular chondrocytes express very little COX-2, COX-2 expression is high in growth plate chondrocytes and is increased by IGF-I. In bovine primary growth plate chondrocytes, ATDC5 cells, and human metatarsal explants, inhibition of COX activity with nonsteroidal antiinflammatory drugs (NSAIDs) inhibits chondrocyte proliferation and ERK activation by IGF-I. This inhibition is reversed by prostaglandin E2 and prostacyclin (PGI2) but not by prostaglandin D2 or thromboxane B2. Inhibition of COX activity in young mice by ip injections of NSAIDs causes dwarfism. In growth plate chondrocytes, inhibition of proliferation and ERK activation by NSAIDs is reversed by forskolin, 8-bromoadenosine, 3',5'-cAMP and a prostacyclin analog, iloprost. The inhibition of proliferation and ERK activation by celecoxib is also reversed by 8CPT-2Me-cAMP, an activator of Epac, implicating the small G protein Rap1 in the pathway activated by iloprost. These results imply that prostacyclin is required for proper growth plate development and bone growth.

Unraveling the mechanisms of action of lactoferrin-derived antihypertensive peptides: ACE inhibition and beyond

The characterization of lactoferrin-derived antihypertensive peptides shows that they might act on several molecular targets.