Differential regulation of prostaglandin E2 and thromboxane A2 production in human monocytes: implications for the use of cyclooxygenase inhibitors

The immunomodulatory function of adenosine in sepsis

Sepsis is an unsolved clinical condition with a substantial mortality rate in the hospital. Despite decades of research, no effective treatments for sepsis exists. The role of adenosine in the pathogenesis of sepsis is discussed in this paper. Adenosine is an essential endogenous molecule that activates the A1, A2a, A2b, and A3 adenosine receptors to regulate tissue function. These receptors are found on a wide range of immune cells and bind adenosine, which helps to control the immune response to inflammation. The adenosine receptors have many regulatory activities that determine the onset and progression of the disease, which have been discovered via the use of animal models. A greater understanding of the role of adenosine in modulating the immune system has sparked hope that an adenosine receptor-targeted treatment may be used one day to treat sepsis.

The emergent phenomenon of aspirin resistance: insights from genetic association studies

Despite the clinical benefits of aspirin, the interindividual variation in response to this antiplatelet drug is considerable. The manifestation of aspirin resistance (AR) is frequently observed, although this complex process remains poorly understood. While AR etiology is likely to be multifactorial, genetic factors appear to be preponderant. According to several genetic association studies, both genome-wide and candidate gene studies, numerous SNPs in cyclooxygenase, thromboxane and platelet receptors-related genes have been identified as capable of negatively affecting aspirin action. Thus, it is essential to understand the clinical relevance of AR-related SNPs as potential predictive and prognostic biomarkers as they may be essential to defining the AR phenotype.

Plantain (Plantago L.) species as modulators of prostaglandin E2 and thromboxane A2 production in inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Worldwide distributed plantains (genus Plantago L.) are extensively used in the traditional, but some of them are also accepted in the modern medicine. Wide range of usages is mainly connected to the inflammation processes.

AIM OF THE STUDY

To support usage of renowned P. lanceolata L. and P. major L., underinvestigated P. altissima L., P. argentea Chaix, P. holosteum Scop. and P. media L. methanol extracts, and their typical constituents (aucubin, apigenin, apigenin-7-O-glucoside, luteolin, luteolin-7-O-glucoside, chlorogenic and ursolic acid) in treatment of inflammation disorders, we conducted study on plantain potential to inhibit production of inflammatory mediators, prostaglandin E₂ (PGE₂) and thromboxane A₂ (TXA₂).

MATERIALS AND METHODS

LPS-stimulated monocytes (U937 cell line) were used as a model-system to examine anti-inflammatory potential of plantains and their constituents. Produced PGE₂ and TXA₂ were quantified by LC-MS/MS; qPCR was applied to examine related gene (PLA₂, COX-1, COX-2, mPGES-1, mPGES-2, cPGES, TXAS) expression; LC-MS/MS and LC-UV/VIS techniques to analyze extracts composition.

RESULTS

In general, examined plantain extracts showed comparable inhibition activity of PGE₂ and TXA₂ production as aspirin at low-dose concentration. Underinvestigated P. altissima can be pointed out, since it exerted the strongest effect on both PGE₂ production and related gene expression. Notable suppression of TXA₂ production by P. lanceolata and P. major was observed. But, PCA analysis showed no obvious grouping, implicating that different mechanisms of action are responsible for each sample activity. In most cases, positive correlation was found between content of apigenin and ursolic acid and extracts suppression of PGE₂ and TXA₂ production and related genes expression.

CONCLUSIONS

P. altissima can be regarded as promising anti-inflammatory agent, while novel aspect of P. lanceolata and P. major application (anti-aggregation) can be suggested. P. argentea and P. media could be considered as a good source of ursolic acid.

The indirubin derivative 6-bromoindirubin-3'-glycerol-oxime ether (6BIGOE) potently modulates inflammatory cytokine and prostaglandin release from human monocytes through GSK-3 interference

Indirubin is a natural bis-indole alkaloid contained as active ingredient in the traditional Chinese remedy Danggui Longhui Wan. Indirubin and its 3'-oxime derivatives exhibit anti-cancer and anti-inflammatory properties and they inhibit glycogen synthase kinase (GSK)-3 in cell-free assays where 6-bromoindirubin-3'-oxime (6BIO) is among the most potent analogs. Here, we reveal 6-bromoindirubin-3'-glycerol-oxime ether (6BIGOE) as highly potent derivative able to inhibit pro-inflammatory cytokine, chemokine and prostaglandin (PG) release in human primary monocytes while increasing anti-inflammatory interleukin (IL)-10 levels. 6BIGOE suppressed lipopolysaccharide (LPS)-induced IL-1β and PGE₂ release with IC₅₀ of 0.008 and 0.02 µM, respectively, being ≥ 12-fold more potent than 6BIO. The effects of 6BIGOE are mediated via intracellular inhibition of GSK-3, where 6BIGOE again surpassed the effectiveness of 6BIO despite the higher potency of the latter in cell-free GSK-3 activity assays. Side-by-side comparison of 6BIGOE (0.1 µM) with the selective GSK-3 inhibitor SB216763 (5 µM) revealed congruent properties such as enrichment of β-catenin and suppression of cyclooxygenase (COX)-2 protein levels due to GSK-3 inhibition. Metabololipidomics using ultra-performance liquid chromatography-tandem mass spectrometry showed that 6BIGOE selectively decreases pro-inflammatory COX-derived product formation without marked modulation of other lipid mediators. In summary, 6BIGOE is a highly potent indirubin derivative in the cellular context that favorably modulates pro- and anti-inflammatory cytokines as well as COX-2-derived PG via interference with GSK-3.

A Lipidomic Perspective of the Action of Group IIA Secreted Phospholipase A2 on Human Monocytes: Lipid Droplet Biogenesis and Activation of Cytosolic Phospholipase A2α

Phospholipase A₂s constitute a wide group of lipid-modifying enzymes which display a variety of functions in innate immune responses. In this work, we utilized mass spectrometry-based lipidomic approaches to investigate the action of Asp-49 Ca²⁺-dependent secreted phospholipase A₂ (sPLA₂) (MT-III) and Lys-49 sPLA2 (MT-II), two group IIA phospholipase A₂s isolated from the venom of the snake Bothrops asper, on human peripheral blood monocytes. MT-III is catalytically active, whereas MT-II lacks enzyme activity. A large decrease in the fatty acid content of membrane phospholipids was detected in MT III-treated monocytes. The significant diminution of the cellular content of phospholipid-bound arachidonic acid seemed to be mediated, in part, by the activation of the endogenous group IVA cytosolic phospholipase A₂α. MT-III triggered the formation of triacylglycerol and cholesterol enriched in palmitic, stearic, and oleic acids, but not arachidonic acid, along with an increase in lipid droplet synthesis. Additionally, it was shown that the increased availability of arachidonic acid arising from phospholipid hydrolysis promoted abundant eicosanoid synthesis. The inactive form, MT-II, failed to produce any of the effects described above. These studies provide a complete lipidomic characterization of the monocyte response to snake venom group IIA phospholipase A₂, and reveal significant connections among lipid droplet biogenesis, cell signaling and biochemical pathways that contribute to initiating the inflammatory response.

Crotalus durissus ruruima Snake Venom and a Phospholipase A2 Isolated from This Venom Elicit Macrophages to Form Lipid Droplets and Synthesize Inflammatory Lipid Mediators

Viper snake Crotalus durissus ruruima (Cdr) is a subspecies found in northern area of Brazil. Among the snakes of Crotalus genus subspecies, the venom of Cdr presents highest level of crotoxin, which is the major component of Crotalus snake venoms, formed by two subunits (crotapotin and a phospholipase A₂ named CBr) and presents potent neurotoxic activity. Curiously, the venom of C. d. ruruima (CdrV) is better neutralized by antibothropic than by anticrotalic serum, strongly suggesting that this venom has similarities with venom of Bothrops genus snakes with regard to the ability to induce inflammation. Macrophages are cells with a central role in inflammatory and immunological responses. Upon inflammatory stimuli, these cells exhibit increased numbers of lipid droplets, which are key organelles in the synthesis and release of inflammatory mediators. However, the effects of CdrV and CBr in macrophage functions are unknown. We herein investigated the ability of CdrV and CBr to activate macrophages with focus on the formation of lipid droplets (LDs), synthesis of lipid mediators, and mechanisms involved in these effects. The involvement of LDs in PGE₂ biosynthesis was also assessed. Stimulation of murine macrophages with CdrV and CBr induced an increased number of LDs and release of prostanoids (PGE₂, PGD₂, and TXB₂). Neither CdrV nor CBr induced the expression of COX-1 and COX-2 by macrophages. LDs induced by both CdrV and CBr are associated to PLIN2 recruitment and expression and were shown to be dependent on COX-1, but not COX-2 activity. Moreover, PGE₂ colocalized to CdrV- and CBr-induced LDs, revealing the role of these organelles as sites for the synthesis of prostanoids. These results evidence, for the first time, the ability of a whole snake venom to induce formation of LDs and the potential role of these organelles for the production of inflammatory mediators during envenomation by Crotalus snakes.

Activity profiling of Serbian and some other European Merlot wines in inflammation and oxidation processes

Merlot are worldwide recognized red wines. Several studies show that red wines have health benefits, mainly due to their phenolic constituents. This study evaluates twelve Serbian and other five European (French, Italian, Macedonian, Slovenian, Spanish) Merlot wines in respect of their phenolic composition and biological activity. The latter was evaluated through a set of in vitro experiments related to common benefits of moderate red wine consumption in the prevention of cardiovascular diseases. Among the examined phenolics, the most abundant acid in all samples was the gallic acid (14.3-58.3 mg/L), catechin (9.1-49.3 mg/L) was the dominant flavonoid, malvidin-3-O-glucoside (2.63-66.5 mg/L) leading anthocyanin, whereas resveratrol was found in a usual concentration (0.18-4.67 mg/L). Differences determined in phenolic profiles, mainly in content of quercetin, rutin and p-coumaric acid, leaded to separation of Serbian from foreing Merlot wines. Results of standard antioxidant assays (DPPH^•, ABTS^•+ and ^•NO scavenger capacity reducing power (FRAP), lipid peroxidation) revealed French Merlot as the most potent, but also pointed out some Serbian samples. The correlation between the content of dominant phenolics and antioxidant activity was sporadic, but samples with the highest overall phenolic content, generally had higher antioxidant potential. Concentration of wines and number of cells in ant-inflammatory assay were chosen to mimic in vivo conditions. So, the potency of examined wines to decrease the production of macrophage-derived PGE₂ and TXA₂ (up to 65.5 and 47.9%, respectively), could be considered as in vitro evidence of positve health effect. Regarding the phenolic content and anti-inflammatory contribution of the most abundant compounds, no correlation was witnessed. In general, this study showed interesting potential of Serbian Merlot wines, comparable to health-promoting effects of renewed Eurepean ones.

Air particulate matter SRM 1648a primes macrophages to hyperinflammatory response after LPS stimulation

Objective

Exposure to air particulate matter (PM) is associated with chronic inflammatory and autoimmune diseases. Macrophages are responsible for the regulation of chronic inflammation. However, whether PM affects macrophage polarization remains unclear. The aim of this study was to evaluate whether nontoxic concentrations of urban PM are able to prime macrophages to altered inflammatory response upon LPS challenge.

Methods

We used two forms of the urban particulate matter SRM 1648a, intact PM and PM deprived of organic compounds (PM∆C). Peritoneal murine macrophages were exposed to different concentrations of PM for 24 h and then challenged with LPS. Production of inflammatory mediators by macrophages was measured to test immunostimulatory/priming capacity of PM.

Results

Particulate matter used at non-cytotoxic concentrations induced a dose-dependent production of proinflammatory cytokines (TNF-α, IL-6, IL-12p40). By contrast, PM∆C were not able to stimulate macrophages. However, macrophages primed with both forms of PM show proinflammatory response upon LPS challenge.

Conclusions

Our data indicate that exposure of macrophages to low concentrations of PM may prime the cells to hyperinflammatory response upon contact with LPS. Further studies are necessary to explain whether the exposure of patients suffering from chronic inflammatory diseases to particulate matter is responsible for the exacerbation of clinical symptoms during bacterial infections.

Differential Impact of Serial Measurement of Nonplatelet Thromboxane Generation on Long-Term Outcome After Cardiac Surgery

BACKGROUND

Systemic thromboxane generation, not suppressible by standard aspirin therapy and likely arising from nonplatelet sources, increases the risk of atherothrombosis and death in patients with cardiovascular disease. In the RIGOR (Reduction in Graft Occlusion Rates) study, greater nonplatelet thromboxane generation occurred early compared with late after coronary artery bypass graft surgery, although only the latter correlated with graft failure. We hypothesize that a similar differential association exists between nonplatelet thromboxane generation and long-term clinical outcome.

METHODS AND RESULTS

Five-year outcome data were analyzed for 290 RIGOR subjects taking aspirin with suppressed platelet thromboxane generation. Multivariable modeling was performed to define the relative predictive value of the urine thromboxane metabolite, 11-dehydrothromboxane B₂ (11-dhTXB₂), measured 3 days versus 6 months after surgery on the composite end point of death, myocardial infarction, revascularization or stroke, and death alone. 11-dhTXB₂ measured 3 days after surgery did not independently predict outcome, whereas 11-dhTXB₂ >450 pg/mg creatinine measured 6 months after surgery predicted the composite end point (adjusted hazard ratio, 1.79; P=0.02) and death (adjusted hazard ratio, 2.90; P=0.01) at 5 years compared with lower values. Additional modeling revealed 11-dhTXB₂ measured early after surgery associated with several markers of inflammation, in contrast to 11-dhTXB₂ measured 6 months later, which highly associated with oxidative stress.

CONCLUSIONS

Long-term nonplatelet thromboxane generation after coronary artery bypass graft surgery is a novel risk factor for 5-year adverse outcome, including death. In contrast, nonplatelet thromboxane generation in the early postoperative period appears to be driven predominantly by inflammation and did not independently predict long-term clinical outcome.

Deriving vascular smooth muscle cells from mesenchymal stromal cells: Evolving differentiation strategies and current understanding of their mechanisms

Vascular smooth muscle cells (VSMCs) play essential roles in regulating blood vessel form and function. Regeneration of functional vascular smooth muscle tissue to repair vascular diseases is an area of intense research in tissue engineering and regenerative medicine. For functional vascular smooth muscle tissue regeneration to become a practical therapy over the next decade, the field will need to have access to VSMC sources that are effective, robust and safe. While pluripotent stem cells hold good future promise to this end, more immediate translation is expected to come from approaches that generate functional VSMCs from adult sources of multipotent adipose-derived and bone marrow-derived mesenchymal stromal cells (ASCs and BMSCs). The research to this end is extensive and is dominated by studies relating to classical biochemical signalling molecules used to induce differentiation of ASCs and BMSCs. However, prolonged use of the biochemical induction factors is costly and can cause potential endotoxin contamination in the culture. Over recent years several non-traditional differentiation approaches have been devised to mimic defined aspects of the native micro-environment in which VSMCs reside to contribute to the differentiation of VSMC-like cells from ASCs and BMSCs. In this review, the promises and limitations of several non-traditional culture approaches (e.g., co-culture, biomechanical, and biomaterial stimuli) targeting VSMC differentiation are discussed. The extensive crosstalk between the underlying signalling cascades are delineated and put into a translational context. It is expected that this review will not only provide significant insight into VSMC differentiation strategies for vascular smooth muscle tissue engineering applications, but will also highlight the fundamental importance of engineering the cellular microenvironment on multiple scales (with consideration of different combinatorial pathways) in order to direct cell differentiation fate and obtain cells of a desired and stable phenotype. These strategies may ultimately be applied to different sources of stem cells in the future for a range of biomaterial and tissue engineering disciplines.

Lipid Mediators in Inflammation

Lipids are potent signaling molecules that regulate a multitude of cellular responses, including cell growth and death and inflammation/infection, via receptor-mediated pathways. Derived from polyunsaturated fatty acids (PUFAs), such as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), each lipid displays unique properties, thus making their role in inflammation distinct from that of other lipids derived from the same PUFA. This diversity arises from their synthesis, which occurs via discrete enzymatic pathways and because they elicit responses via different receptors. This review will collate the bioactive lipid research to date and summarize the major pathways involved in their biosynthesis and role in inflammation. Specifically, lipids derived from AA (prostanoids, leukotrienes, 5-oxo-6,8,11,14-eicosatetraenoic acid, lipoxins, and epoxyeicosatrienoic acids), EPA (E-series resolvins), and DHA (D-series resolvins, protectins, and maresins) will be discussed herein.

Impact of FDA-Approved Drugs on the Prostaglandin Transporter OATP2A1/SLCO2A1

To understand interaction of drugs with the prostaglandin transporter OATP2A1/SLCO2A1 that regulates disposition of prostaglandins, we explored the impact of 636 drugs in an FDA-approved drug library on 6-carboxyfluorescein (6-CF) uptake by OATP2A1-expressing HEK293 cells (HEK/2A1). Fifty-one and 10 drugs were found to inhibit and enhance 6-CF uptake by more than 50%, respectively. Effect of the 51 drugs on 6-CF uptake was positively correlated with that on PGE₂ uptake (r = 0.64, p < 0.001). Among those, 5 drugs not structurally related to prostaglandins, suramin, pranlukast, zafirlukast, olmesartan medoxomil, and losartan potassium, exhibited more than 90% PGE₂ uptake inhibition. Inhibitory affinity of suramin to OATP2A1 was the highest (IC_50,2A1 of 0.17 μM), and its IC₅₀ values to MRP4-mediated PGE₂ transport (IC_50,MRP4) and PGE₂ synthesis in human U-937 cells treated with phorbol 12-myristate 13-acetate (IC_50,Syn) were 73.6 and 336.7 times higher than IC_50,2A1, respectively. Moreover, structure-activity relationship study in 29 nonsteroidal anti-inflammatory drugs contained in the library displayed inhibitory activities of anthranilic acid derivatives, but enhancing effects of propionic acid derivatives. These results demonstrate that suramin is a potent selective inhibitor of OATP2A1, providing a comprehensive information about drugs in clinical use that interact with OATP2A1.

Olive oil compounds inhibit the paracrine regulation of TNF-α-induced endothelial cell migration through reduced glioblastoma cell cyclooxygenase-2 expression

The established causal relationship between the chronic inflammatory microenvironment, tumor development and cancer recurrence has provided leads for developing novel preventive strategies. Accumulating experimental, clinical and epidemiological data has provided support for the chemopreventive properties of olive oil compounds traditionally found within the Mediterranean diet. In this study, we investigated whether tyrosol (Tyr), hydroxytyrosol, oleuropein and oleic acid (OA), four compounds contained in extra virgin olive oil, can prevent tumor necrosis factor (TNF)-α-induced expression of cyclooxygenase (COX)-2 (an inflammation biomarker) in a human glioblastoma cell (U-87 MG) model. We found that Tyr and OA significantly inhibited TNF-α-induced COX-2 gene and protein expression, as well as PGE2 secretion. Both compounds also inhibited TNF-α-induced JNK and ERK phosphorylation, whereas only Tyr inhibited TNF-α-induced NF-κB phosphorylation. Paracrine-regulated migration of human brain microvascular endothelial cells (HBMECs) was assessed using growth factor-enriched conditioned media (CM) isolated from U-87 MG cells. We found that while PGE2 triggered HBMEC migration, the CM isolated from U-87 MG cells, where either COX-2 or NF-κB had been silenced or had been treated with Tyr or OA, exhibited decreased chemotactic properties. These observations demonstrate that olive oil compounds inhibit the effect of the chronic inflammatory microenvironment on glioblastoma progression through TNF-α actions and may be useful in cancer chemoprevention.

Flurbiprofen axetil increases arterial oxygen partial pressure by decreasing intrapulmonary shunt in patients undergoing one-lung ventilation

PURPOSES

In the present study, we investigated whether flurbiprofen axetil (FA) alleviates hypoxemia during one-lung ventilation (OLV) by reducing the pulmonary shunt/total perfusion (Q s/Q t) ratio, and examined the relationship between the Q s/Q t ratio and the thromboxane B2 (TXB2)/6-keto-prostaglandin F1α (6-K-PGF1α) ratio.

METHODS

Sixty patients undergoing esophageal resection for carcinoma were randomly assigned to groups F and C (n = 30 for each group). FA and placebo were administered i.v. 15 min before skin incision in groups F and C, respectively. The partial pressure of arterial oxygen (PaO2) was measured and the Q s/Q t ratio was calculated. Serum TXB2, 6-K-PGF1α, and endothelin (ET) were measured by radioimmunoassay. The relationship between TXB2/6-K-PGF1α and Q s/Q t was investigated.

RESULTS

Compared with group C, PaO2 was higher and the Q s/Q t ratio was lower during OLV in group F (P < 0.05). After treatment with FA, both serum TXB2 and 6-K-PGF1α decreased significantly (P < 0.05) but the TXB2/6-K-PGF1α ratio increased significantly (P < 0.01). Increases in the TXB2/6-K-PGF1α ratio were correlated with reductions in the Q s/Q t ratio during OLV in group F (r = -0.766, P < 0.01). There was no significant difference in serum ET between groups F and C.

CONCLUSIONS

Treatment with FA reduced the Q s/Q t ratio and further increased the PaO2 level during OLV, possibly due to upregulation of the vasoactive agent TXB2/6-K-PGF1α ratio.

Relationship of the Topological Distances and Activities between mPGES-1 and COX-2 versus COX-1: Implications of the Different Post-Translational Endoplasmic Reticulum Organizations of COX-1 and COX-2

In vascular inflammation, prostaglandin E2 (PGE₂) is largely biosynthesized by microsomal PGE₂ synthase-1 (mPGES-1), competing with other downstream eicosanoid-synthesizing enzymes, such as PGIS, a synthase of a vascular protector prostacyclin (PGI₂), to isomerize the cyclooxygenase (COX)-2-derived prostaglandin H2 (PGH₂). In this study, we found that a majority of the product from the cells co-expressing human COX-2, mPGES-1, and PGIS was PGE₂. We hypothesize that the molecular and cellular mechanisms are related to the post-translational endoplasmic reticulum (ER) arrangement of those enzymes. A set of fusion enzymes, COX-2-linker [10 amino acids (aa)]-PGIS and COX-2-linker (22 amino acids)-PGIS, were created as "The Bioruler", in which the 10 and 22 amino acids are defined linkers with known helical structures and distances (14.4 and 30.8 Å, respectively). Our experiments have shown that the efficiency of PGI₂ biosynthesis was reduced when the separation distance increased from 10 to 22 amino acids. When COX-2-10aa-PGIS (with a 14.4 Å separation) was co-expressed with mPGES-1 on the ER membrane, a major product was PGE₂, but not PGI₂. However, expression of COX-2-10aa-PGIS and mPGES-1 on a separated ER with a distance of ≫30.8 Å reduced the level of PGE₂ production. These data indicated that the mPGES-1 is "complex-likely" colocalized with COX-2 within a distance of 14.4 Å. In addition, the cells co-expressing COX-1-10aa-PGIS and mPGES-1 produced PGI₂ mainly, but not PGE₂. This indicates that mPGES-1 is expressed much farther from COX-1. These findings have led to proposed models showing the different post-translational ER organization between COX-2 and COX-1 with respect to the topological arrangement of the mPGES-1 during vascular inflammation.

Cytotoxicity evaluation of biodegradable Zn-3Mg alloy toward normal human osteoblast cells

The recent proposal of using Zn-based alloys for biodegradable implants was not supported with sufficient toxicity data. This work, for the first time, presents a thorough cytotoxicity evaluation of Zn-3Mg alloy for biodegradable bone implants. Normal human osteoblast cells were exposed to the alloy's extract and three main cell-material interaction parameters: cell health, functionality and inflammatory response, were evaluated. Results showed that at the concentration of 0.75mg/ml alloy extract, cell viability was reduced by ~50% through an induction of apoptosis at day 1; however, cells were able to recover at days 3 and 7. Cytoskeletal changes were observed but without any significant DNA damage. The downregulation of alkaline phosphatase protein levels did not significantly affect the mineralization process of the cells. Significant differences of cyclooxygenase-2 and prostaglandin E2 inflammatory biomarkers were noticed, but not interleukin 1-beta, indicating that the cells underwent a healing process after exposure to the alloy. Detailed analysis on the cell-material interaction is further discussed in this paper.

Methanolic Extract of Asterina pectinifera inhibits LPS-Induced Inflammatory Mediators in Murine Macrophage

This study aimed to elucidate anti-inflammatory activities from extracts of Asterina pectinifera on nitric oxide (NO) production, TNF-α and IL-6 release in lipopolysaccharide (LPS) -stimulated murine macrophage cell, RAW264.7. We prepared the methanolic extracts (60-MAP, 70-MAP, 80-MAP and 90-MAP) , aqueous extract (W-AP) and functional bioactive compound fraction (He-AP and EA-AP) from Asterina pectinifera according to extract method. The 60-MAP, 70-MAP, 80-MAP, 90-MAP and W-AP were significantly suppressed LPS-induced production NO, TNF-α and IL-6 secretion in a concentration-dependent manner (P < 0.05) . Especially, 80-MAP by extracted 80% methanol had the strongest activity in reduction of inflammatory mediators among these extracts. Indeed, to identify active fraction, which contained potential bioactive compounds, from 80-MAP of Asterina pectinifera, we tested anti-inflammatory activity of the He-AP or the EA-AP. The He-AP was next extracted from 80-MAP and the EA-AP were extracted from the other methanol layer except the He-AP. The EA-AP demonstrated a strong anti-inflammatory effect through its ability to reduce NO production and it also inhibited the production of proinflammatory cytokines such as IL-6 and TNF-α at low concentration. These results suggested that the methanolic extract from Asterina pectinifera had the potential inhibitory effects on the production of these inflammatory mediators.

Aspirate from human stented native coronary arteries vs. saphenous vein grafts: more endothelin but less particulate debris

Stent implantation into atherosclerotic coronary arteries releases particulate debris and soluble substances that contribute to impaired microvascular perfusion. Here we addressed the potential for microvascular obstruction in patients with stenotic native right coronary arteries (nRCA) compared with saphenous vein grafts on right coronary arteries (SVG-RCA). We enrolled symptomatic, male patients with stable angina pectoris and a flow-limiting stenosis in their nRCA or SVG-RCA ( n = 18/18). Plaque volume and composition were analyzed using intravascular ultrasound before stent implantation. Coronary aspirate was retrieved during stent implantation under protection with a distal occlusion/aspiration device and divided into particulate debris and plasma. The release of catecholamines, endothelin, serotonin, thromboxane B2, and tumor necrosis factor-α was measured. The response of rat mesenteric arteries with intact (+E) and denuded (−E) endothelium to aspirate plasma (without and with selective endothelin receptor blockade) was normalized to that by potassium chloride (KClmax = 100%). Plaque volume and composition were not different between nRCA and SVG-RCA. There was less particulate debris (65 ± 8 vs. 146 ± 23 mg; P < 0.05) and more endothelin release (5.8 ± 0.8 vs. 1.3 ± 0.7 pg/ml; P < 0.05) in nRCA than in SVG-RCA, whereas the release of the other mediators was not different. Aspirate from nRCA induced stronger vasoconstriction than that from SVG-RCA [nRCA, 78 ± 6% (+E)/84 ± 5% (−E); SVG-RCA, 59 ± 6% (+E)/68 ± 3% (−E); P < 0.05 nRCA vs. SVG-RCA], which was attenuated by a nonspecific endothelin and a specific endothelin receptor A antagonist. Thus coronary aspirate from stented nRCA is characterized by less debris but more endothelin and stronger vasoconstrictor response than that from SVG-RCA.

HPLC-PDA Analysis and Anti-inflammatory Effects of Mori Cortex Radicis

Mori Cortex Radicis (MCR, Moraceae) is used traditionally in the treatment of jaundice, hematemesis, edema, and pollakisuria in Korea. In this study, the anti-inflammatory effects of MCR extract were investigated using RAW 264.7 cells. The simultaneous analysis of five components present (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, caffeic acid, and p-coumaric acid) in the MCR extract was performed using high-performance liquid chromatography (HPLC) coupled with photodiode array (PDA) detection. We determined the effects of MCR extract and its components on the production of nitric oxide (NO), prostaglandin E2 (PGE2), and mRNA expression of cyclooxygenase-2 (COX-2) in RAW 264.7 cells. MCR extract suppressed the production of NO and PGE2 in RAW 264.7 cells in a dose-dependent manner. None of the five components of the MCR extract had any influence on the production of NO. However, caffeic acid and p-coumaric acid inhibited the production of PGE2 and mRNA expression of COX-2 in RAW 264.7 cells. Our results suggest that MCR extract may offer potential as a therapeutic agent for the treatment of inflammation. The method we have established will help to improve the quality control of MCR extracts.

Mechanisms of aspirin resistance

Aspirin is integral to the secondary prevention of cardiovascular disease and acts to impair the development of platelet-mediated atherothromboembolic events by irreversible inhibition of platelet cyclooxygenase-1 (COX-1). Inhibition of this enzyme prevents the synthesis of the potent pro-aggregatory prostanoid thromboxane A2. A large number of patients continue to experience atherothromboembolic events despite aspirin therapy, so-called 'aspirin treatment failure', and this is multifactorial in aetiology. Approximately 10% however do not respond appropriately to aspirin in a phenomenon known as 'aspirin resistance', which is defined by various laboratory techniques. In this review we discuss the reasons for aspirin resistance in a systematic manner, starting from prescription of the drug and ending at the level of the platelet. Poor medication adherence has been shown to be a cause of apparent aspirin resistance, and may in fact be the largest contributory factor. Also important is high platelet turnover due to underlying inflammatory processes, such as atherosclerosis and its complications, leading to faster regeneration of platelets, and hence of COX-1, at a rate that diminishes the efficacy of once daily dosing. Recent developments include the identification of platelet glycoprotein IIIa as a potential biomarker (as well as possible underlying mechanism) for aspirin resistance and the discovery of an anion efflux pump that expels intracellular aspirin from platelets. The absolute as well as relative contributions of such factors to the phenomenon of aspirin resistance are the subject of continuing research.

Coronary aspirate TNFα reflects saphenous vein bypass graft restenosis risk in diabetic patients

BACKGROUND

Patients with diabetes mellitus (DM) have an increased risk for periprocedural complications and adverse cardiac events after percutaneous coronary intervention. We addressed the potential for coronary microvascular obstruction and restenosis in patients with and without DM undergoing stenting for saphenous vein bypass graft (SVG) stenosis under protection with a distal occlusion/aspiration device.

METHODS

SVG plaque volume and composition were analyzed using intravascular ultrasound before stent implantation. Percent diameter stenosis was determined from quantitative coronary angiography before, immediately after and 6 months after stent implantation. Coronary aspirate was retrieved during stent implantation and divided into particulate debris and plasma. Total calcium, several vasoconstrictors, and tumor necrosis factor (TNF)α in particulate debris and coronary aspirate plasma were determined.

RESULTS

Patients with and without DM had similar plaque volume, but larger necrotic core and greater particulate debris release in patients with than without DM (20.3±2.7 vs. 12.7±2.6% and 143.9±19.3 vs. 75.1±10.4 mg, P<0.05). The TNFα concentration in particulate debris and coronary aspirate plasma was higher in patients with than without DM (15.9±6.6 vs. 5.1±2.4 pmol/mg and 2.2±0.7 vs. 1.1±0.2 pmol/L, P<0.05), whereas total calcium and vasoconstrictors were not different. Patients with DM had a greater percent diameter stenosis 6 months after stent implantation than those without DM (22.17±5.22 vs. 6.34±1.11%, P<0.05). The increase in TNFα immediately after stent implantation correlated with restenosis 6 months later (r=0.69, P<0.05).

CONCLUSION

In diabetics, particulate debris and coronary aspirate plasma contained more TNFα, which might reflect the activity of the underlying atherosclerotic process.

TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov/ct2/results?term=NCT01430884; unique identifier: NCT01430884.

Saphenous vein aorto-coronary graft atherosclerosis in patients with chronic kidney disease: more plaque calcification and necrosis, but less vasoconstrictor potential

Atherosclerotic coronary arteries are more calcified in patients with than without chronic kidney disease (CKD). We addressed the potential for coronary microvascular obstruction in patients with and without CKD during stenting for saphenous vein aorto-coronary graft (SVG) stenosis under protection with a distal occlusion/aspiration device. In patients with and without CKD (n = 20/20), SVG plaque composition was analyzed from virtual histology using intravascular ultrasound analysis before stent implantation. There was more dense calcium and more necrotic core in patients with than without CKD (14 ± 3 vs. 3 ± 1 % and 21 ± 3 vs. 12 ± 2 % of plaque volume, respectively). Coronary aspirate was retrieved during stent implantation and divided into particulate debris and plasma. Patients with CKD had more particulate debris and calcium release than patients without CKD. In contrast, the release of serotonin was less in patients with than without CKD (0.4 ± 0.1 vs. 1.2 ± 0.3 μmol/L), whereas that of catecholamines, endothelin, tissue factor, thromboxane, tumor necrosis factor α, and C reactive protein was not significantly different. Confirming the biochemical results, aspirate plasma from patients with CKD induced less vasoconstriction of rat mesenteric arteries than that from patients without CKD (with endothelium (+E), 26 ± 7 %; without endothelium (-E): 28 ± 7 % vs. +E, 68 ± 12 %; -E: 95 ± 16 % of maximum KCl-induced vasoconstriction). Graft atherosclerosis of patients with CKD is more degenerated and releases more particulate debris and calcium, but the aspirate has surprisingly less serotonin and vasoconstrictor potential.

Prostaglandin E2 and the suppression of phagocyte innate immune responses in different organs

The local and systemic production of prostaglandin E₂ (PGE₂) and its actions in phagocytes lead to immunosuppressive conditions. PGE₂ is produced at high levels during inflammation, and its suppressive effects are caused by the ligation of the E prostanoid receptors EP₂ and EP₄, which results in the production of cyclic AMP. However, PGE₂ also exhibits immunostimulatory properties due to binding to EP₃, which results in decreased cAMP levels. The various guanine nucleotide-binding proteins (G proteins) that are coupled to the different EP receptors account for the pleiotropic roles of PGE₂ in different disease states. Here, we discuss the production of PGE₂ and the actions of this prostanoid in phagocytes from different tissues, the relative contribution of PGE₂ to the modulation of innate immune responses, and the novel therapeutic opportunities that can be used to control inflammatory responses.

Thromboxane receptor signaling is required for fibronectin-induced matrix metalloproteinase 9 production by human and murine macrophages and is attenuated by the Arhgef1 molecule

During an inflammatory response, resident and newly recruited tissue macrophages adhere to extracellular matrix and cell-bound integrin ligands. This interaction induces the expression of pro-inflammatory mediators that include matrix metalloproteinases (MMPs). Arhgef1 is an intracellular signaling molecule expressed by myeloid cells that normally attenuates murine macrophage MMP production in vivo and in vitro after cell culture on the extracellular matrix protein, fibronectin. In this study, we have extended the characterization of this fibronectin-induced Arhgef1-regulated signaling pathway in both human and murine myeloid cells. Our results show that MMP9 production by fibronectin-stimulated monocytes and macrophages depends on autocrine thromboxane receptor signaling and that under normal conditions, this signaling pathway is attenuated by Arhgef1. Finally, we show that the expression of ARHGEF1 by human peripheral blood monocytes varies between individuals and inversely correlates with fibronectin-mediated MMP9 production.

Monocyte-platelet interaction induces a pro-inflammatory phenotype in circulating monocytes

Background

Activated platelets exert a pro-inflammatory action that can be largely ascribed to their ability to interact with leukocytes and modulate their activity. We hypothesized that platelet activation and consequent formation of monocyte-platelet aggregates (MPA) induces a pro-inflammatory phenotype in circulating monocytes.

Methodology/Principal Findings

CD62P⁺ platelets and MPA were measured, and monocytes characterized, by whole blood flow cytometry in healthy subjects, before and two days after receiving influenza immunization. Three monocytic subsets were identified: CD14⁺CD16⁻, CD14^highCD16⁺and CD14^lowCD16⁺. The increase in high sensitivity C-reactive protein post-immunization was accompanied by increased platelet activation and MPA formation (25.02±12.57 vs 41.48±16.81; p = 0.01), along with enhancement of circulating CD14^highCD16⁺ cells (4.7±3.6 vs 10.4±4.8; p = 0.003), their percentage being linearly related to levels of CD62P⁺-platelets (r² = 0.4347; p = 0.0008). In separate in vitro experiments, co-incubation of CD14⁺CD16⁻ cells, isolated from healthy donor subjects, with autologous platelets gave rise to up-regulation of CD16 on monocytes as compared with those maintained in medium alone (% change in CD14⁺CD16⁺ cells following 48 h co-incubation of monocytes with platelets was +106±51% vs monocytes in medium alone; p<0.001). This effect correlated directly with degree of MPA formation (r² = 0.7731; p<0.0001) and was associated with increased monocyte adhesion to endothelial cells. P-selectin glycoprotein ligand-1 (PSGL-1) blocking antibody, which abrogates MPA formation, abolished these effects, as did the cyclooxygenase (COX)-2 selective inhibitor NS-398, aspirin and the EP1/EP2-selective antagonist AH6809.

Conclusions/Significance

These data suggest that MPA formation, as occurs in the blood under pro-inflammatory conditions, expands the pool of circulating CD14^highCD16⁺ monocytes in a COX-2 dependent manner, and these monocytes exhibit increased adhesion to endothelium. Our findings delineate a novel mechanism underlying the pro-inflammatory effect of platelet activation.

Lessons from human coronary aspirate

The interventional implantation of a stent into an atherosclerotic coronary artery is a unique and paradigmatic scenario of plaque rupture in humans. The use of protection devices not only prevents the released plaque particles and the superimposed thrombotic material from being washed and embolized into the coronary microcirculation of the individual patient, but permits also the retrieval and ex vivo analysis of particulate plaque debris and soluble substances. The particulate debris comprises typical cholesterol crystals, foam cells, hyalin material and calcium deposits from the atheroma as well as platelets and coagulation material; soluble substances include vasoconstrictors, such as serotonin and thromboxane, as well as inflammatory mediators, such as TNFα which amplifies vasoconstriction by inducing endothelial dysfunction. The vasoconstriction observed in a bioassay ex vivo correlates to clinical symptoms, angiographic stenosis and plaque burden, as assessed by intravascular ultrasound. The release of TNFα into the aspirate correlates to restenosis. Detailed analysis of the human coronary aspirate may promote a better understanding of the pathophysiology of the vulnerable atherosclerotic plaque and help to better antagonize the microvascular consequences of coronary microembolization, including the no reflow phenomenon. This article is part of a Special Issue entitled "Coronary Blood Flow."

Specificity of eicosanoid production depends on the TLR-4-stimulated macrophage phenotype

Eicosanoid metabolism differs in profile and quantity between macrophages of different tissue origin and method of elicitation, as well as between primary and immortalized macrophages after activation with inflammatory stimuli. Using a lipidomic approach, we comprehensively analyzed the eicosanoids made by murine RPMs, TGEMs, BMDM, and the macrophage-like cell line RAW after stimulation with the TLR-4-specific agonist KLA. Direct correlation among total COX metabolites, COX side-products (11-HETE, 15-HETE), COX-2 mRNA, and protein at 8 h was found when comparing each cell type. Comprehensive qPCR analysis was used to compare relative transcript levels between the terminal prostanoid synthases themselves as well as between each cell type. Levels of PGE(2), PGD(2), and TxB(2) generally correlated with enzyme transcript expression of PGES, PGDS, and TBXS, providing evidence of comparable enzyme activities. PGIS transcript was expressed only in RPM and TGEM macrophages and at an exceptionally low level, despite high metabolite production compared with other synthases. Presence of PGIS in RPM and TGEM also lowered the production of PGE(2) versus PGD(2) by approximately tenfold relative to BMDM and RAW cells, which lacked this enzyme. Our results demonstrate that delayed PG production depends on the maximal level of COX-2 expression in different macrophages after TLR-4 stimulation. Also, the same enzymes in each cell largely dictate the profile of eicosanoids produced depending on the ratios of expression between them, with the exception of PGIS, which appears to have much greater synthetic capacity and competes selectively with mPGES-1.

Long-term use of aspirin and the risk of gastrointestinal bleeding

BACKGROUND

In short-term trials, aspirin is associated with gastrointestinal bleeding. However, the effect of dose and duration of aspirin use on risk remains unclear.

METHODS

We conducted a prospective study of 87,680 women enrolled in the Nurses' Health Study in 1990 who provided biennial data on aspirin use. We examined the relative risk (RR) of major gastrointestinal bleeding requiring hospitalization or blood transfusion.

RESULTS

During a 24-year follow-up, 1537 women reported a major gastrointestinal bleeding. Among women who used aspirin regularly (≥2 standard [325 mg] tablets/week), the multivariate RR of gastrointestinal bleeding was 1.43 (95% confidence interval [CI], 1.29-1.59) when compared with nonregular users. Compared with women who denied any aspirin use, the multivariate RRs of gastrointestinal bleeding were 1.03 (95% CI, 0.85-1.24) for women who used 0.5 to 1.5 standard aspirin tablets/week, 1.30 (95% CI, 1.07-1.58) for women who used 2 to 5 tablets/week, 1.77 (95% CI, 1.44-2.18) for women who used 6 to 14 tablets/week, and 2.24 (95% CI, 1.66-3.03) for women who used more than 14 tablets/week (P(trend)<.001). Similar dose-response relationships were observed among short-term users (≤5 years; P(trend)<.001) and long-term users (>5 years; P(trend)<.001). In contrast, after adjustments were made for dose, increasing duration of use did not confer a greater risk of bleeding (P(trend) = .28).

CONCLUSION

Regular aspirin use is associated with gastrointestinal bleeding. Risk seems more strongly related to dose than duration of aspirin use. Efforts to minimize adverse effects of aspirin therapy should emphasize using the lowest effective dose among both short- and long-term users.

Vasoconstrictor Potential of Coronary Aspirate From Patients Undergoing Stenting of Saphenous Vein Aortocoronary Bypass Grafts and Its Pharmacological Attenuation

Rationale:

Stent implantation into atherosclerotic plaques releases, apart from particulate debris, soluble substances that contribute to impaired microvascular perfusion.

Objective:

To quantify the release of vasoconstrictors and to determine the efficacy of coronary dilators to attenuate their action.

Methods and Results:

Using a distal protection/aspiration device, coronary arterial blood was retrieved before and during stenting in 22 patients with severe saphenous vein aorto-coronary bypass stenoses. The release of catecholamines, endothelin, serotonin, thromboxane B 2 , and tumor necrosis factor (TNF)α was measured. The response of rat mesenteric arteries with intact (+E) and denuded (−E) endothelium to aspirate plasma was normalized to that by KCl. Responses to selective receptor blockade, adenosine, nitroprusside, and verapamil against the aspirate-induced constriction were determined. The coronary arterial plasma withdrawn before stenting induced 21±5% and the aspirate plasma after stenting induced 95±8% of maximum KCl-induced vasoconstriction. Serotonin, thromboxane B 2 , and TNFα release into aspirate plasma increased by 1.9±0.2 μmol/L, 25.6±3.1 pg/mL, and 19.7±6.1 pg/mL, respectively, during stenting. The aspirate-induced vasoconstriction was largely antagonized by selective serotonin receptor blockade, with little further antagonism by additional thromboxane receptor blockade. TNFα did not induce constriction per se but potentiated the constriction with serotonin and the thromboxane-analog U-46619 in arteries +E. The concentrations to induce half-maximal vasodilation were comparable for nitroprusside (+E, 3.3×10 −8 ; −E, 1.9×10 −8 mol/L) and verapamil (+E, 8.3×10 −8 ; −E, 7.8×10 −8 mol/L), and the vasoconstriction was eventually eliminated. The vasodilator response to adenosine was dependent on functional endothelium and weaker.

Conclusion:

Serotonin is the main coronary vasoconstrictor after stenting, and thromboxane and TNFα somewhat potentiate the serotonin response. Nitroprusside and verapamil are more potent than adenosine to attenuate the aspirate plasma-induced vasoconstriction, and they are not dependent on functional endothelium.

A prospective study of aspirin use and the risk of gastrointestinal bleeding in men

BACKGROUND AND AIMS

Data regarding the influence of dose and duration of aspirin use on risk of gastrointestinal bleeding are conflicting.

METHODS

We conducted a prospective cohort study of 32,989 men enrolled in the Health Professionals Follow-up Study (HPFS) in 1994 who provided biennial aspirin data. We estimated relative risk of major gastrointestinal bleeding requiring hospitalization or a blood transfusion.

RESULTS

During 14 years of follow-up, 707 men reported an episode of major gastrointestinal bleeding over 377,231 person-years. After adjusting for risk factors, regular aspirin use (≥2 times/week) had a multivariate relative risk (RR) of gastrointestinal bleeding of 1.32 (95% confidence interval [CI], 1.12-1.55) compared to non-regular use. The association was particularly evident for upper gastrointestinal bleeding (multivariate RR, 1.49; 95% CI, 1.16-1.92). Compared to men who denied any aspirin use, multivariate RRs of upper gastrointestinal bleeding were 1.05 (95% CI 0.71-1.52) for men who used 0.5-1.5 standard tablets/week, 1.31 (95% CI 0.88-1.95) for 2-5 aspirin/week, 1.63 (95% CI, 1.15-2.32) for 6-14 aspirin/week and 2.40 (95% CI, 1.10-5.22) for >14 aspirin/week (P(trend)<0.001). The relative risk also appeared to be dose-dependent among short-term users <5 years; P(trend)<.001) and long-term users (≥5 years; P(trend) = 0.015). In contrast, after controlling for dose, increasing duration of use did not appear to be associated with risk (P(trend) = 0.749).

CONCLUSIONS

Regular aspirin use increases the risk of gastrointestinal bleeding, especially from the upper tract. However, risk of bleeding appears to be more strongly related to dose than to duration of use. Risk of bleeding should be minimized by using the lowest effective dose among short-term and long-term aspirin users.

Old and new generation lipid mediators in acute inflammation and resolution

Originally regarded as just membrane constituents and energy storing molecules, lipids are now recognised as potent signalling molecules that regulate a multitude of cellular responses via receptor-mediated pathways, including cell growth and death, and inflammation/infection. Derived from polyunsaturated fatty acids (PUFAs), such as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), each lipid displays unique properties, thus making their role in inflammation distinct from that of other lipids derived from the same PUFA. The diversity of their actions arises because such metabolites are synthesised via discrete enzymatic pathways and because they elicit their response via different receptors. This review will collate the bioactive lipid research to date and summarise the findings in terms of the major pathways involved in their biosynthesis and their role in inflammation and its resolution. It will include lipids derived from AA (prostanoids, leukotrienes, 5-oxo-6,8,11,14-eicosatetraenoic acid, lipoxins and epoxyeicosatrienoic acids), EPA (E-series resolvins), and DHA (D-series resolvins, protectins and maresins).

The Anti-inflammatory Effects of Water Extract from Cordyceps militaris in Murine Macrophage

The aim of this study was to determine the in vitro anti-inflammatory effect of hot water extract from Cordyceps militaris fruiting bodies (CMWE) on lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release in RAW 264.7 cells. The treatment of macrophages with various concentrations of hot CMWE significantly reduced LPS-induced production as well as NO, TNF-α and IL-6 secretion in a concentration-dependent manner. These results suggest that CMWE have potent inhibitory effects on the production of these inflammatory mediators.

Elevated ratio of urinary metabolites of thromboxane and prostacyclin is associated with adverse cardiovascular events in ADAPT

Results from prevention trials, including the Alzheimer's Disease Anti-inflammatory Prevention Trial (ADAPT), have fueled discussion about the cardiovascular (CV) risks associated with non-steroidal anti-inflammatory drugs (NSAIDs). We tested the hypotheses that (i) adverse CV events reported among ADAPT participants (aged 70 years and older) are associated with increased ratio of urine 11-dehydrothromboxane B₂ (Tx-M) to 2′3-donor–6-keto-PGF1 (PGI-M) attributable to NSAID treatments; (ii) coincident use of aspirin (ASA) would attenuate NSAID-induced changes in Tx-M/PGI-M ratio; and (iii) use of NSAIDs and/or ASA would not alter urine or plasma concentrations of F₂-isoprostanes (IsoPs), in vivo biomarkers of free radical damage. We quantified urine Tx-M and PGI-M, and urine and plasma F₂-IsoPs from 315 ADAPT participants using stable isotope dilution assays with gas chromatography/mass spectrometry, and analyzed these data by randomized drug assignment and self-report compliance as well as ASA use. Adverse CV events were significantly associated with higher urine Tx-M/PGI-M ratio, which seemed to derive mainly from lowered PGI-M. Participants taking ASA alone had reduced urine Tx-M/PGI-M compared to no ASA or NSAID; however, participants taking NSAIDs plus ASA did not have reduced urine Tx-M/PGI-M ratio compared to NSAIDs alone. Neither NSAID nor ASA use altered plasma or urine F₂-IsoPs. These data suggest a possible mechanism for the increased risk of CV events reported in ADAPT participants assigned to NSAIDs, and suggest that the changes in the Tx-M/PGI-M ratio was not substantively mitigated by coincident use of ASA in individuals 70 years or older.

Suppressive effect of secretory phospholipase A2 inhibitory peptide on interleukin-1beta-induced matrix metalloproteinase production in rheumatoid synovial fibroblasts, and its antiarthritic activity in hTNFtg mice

INTRODUCTION

Secretory phospholipase A2 (sPLA2) and matrix metalloproteinase (MMP) inhibitors are potent modulators of inflammation with therapeutic potential, but have limited efficacy in rheumatoid arthritis (RA). The objective of this study was to understand the inhibitory mechanism of phospholipase inhibitor from python (PIP)-18 peptide in cultured synovial fibroblasts (SF), and to evaluate its therapeutic potential in a human tumor necrosis factor (hTNF)-driven transgenic mouse (Tg197) model of arthritis.

METHODS

Gene and protein expression of sPLA2-IIA, MMP-1, MMP-2, MMP-3, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, and TIMP-2 were analyzed by real time PCR and ELISA respectively, in interleukin (IL)-1beta stimulated rheumatoid arthritis (RA) and osteoarthritis (OA) synovial fibroblasts cells treated with or without inhibitors of sPLA2 (PIP-18, LY315920) or MMPs (MMP Inhibitor II). Phosphorylation status of mitogen-activated protein kinase (MAPK) proteins was examined by cell-based ELISA. The effect of PIP-18 was compared with that of celecoxib, methotrexate, infliximab and antiflamin-2 in Tg197 mice after ip administration (thrice weekly for 5 weeks) at two doses (10, 30 mg/kg), and histologic analysis of ankle joints. Serum sPLA2 and cytokines (tumor necrosis factor (TNF)alpha, IL-6) were measured by Escherichia coli (E coli) assay and ELISA, respectively.

RESULTS

PIP-18 inhibited sPLA2-IIA production and enzymatic activity, and suppressed production of MMPs in IL-1beta-induced RA and OA SF cells. Treatment with PIP-18 blocked IL-1beta-induced p38 MAPK phosphorylation and resulted in attenuation of sPLA2-IIA and MMP mRNA transcription in RA SF cells. The disease modifying effect of PIP-18 was evidenced by significant abrogation of synovitis, cartilage degradation and bone erosion in hTNF Tg197 mice.

CONCLUSIONS

Our results demonstrate the benefit that can be gained from using sPLA2 inhibitory peptide for RA treatment, and validate PIP-18 as a potential therapeutic in a clinically relevant animal model of human arthritis.

Prostaglandin E2 inhibits advanced glycation end product-induced adhesion molecule expression, cytokine production, and lymphocyte proliferation in human peripheral blood mononuclear cells

Advanced glycation end product (AGE) subtypes, proteins or lipids that become glycated after exposure to sugars, induce complications in diabetes. Among the various AGE subtypes, glyceraldehyde-derived AGE (AGE-2) and glycolaldehyde-derived AGE (AGE-3) have been indicated to play roles in inflammation in diabetic patients. The engagement of AGEs and receptor for AGEs activates monocytes. Because the engagement of intercellular adhesion molecule-1 (ICAM-1), B7.1, B7.2, and CD40 on monocytes with their ligands on T cells plays roles in cytokine production, we investigated the effects of AGE-2 and AGE-3 on the expressions of ICAM-1, B7.1, B7.2, and CD40 on monocytes, the production of interferon gamma and tumor necrosis factor alpha, and the lymphocyte proliferation in human peripheral blood mononuclear cells and their modulation by prostaglandin E(2) (PGE(2)). AGE-2 and AGE-3 induced the expressions of adhesion molecule, the cytokine production, and the lymphocyte proliferation. PGE(2) concentration-dependently inhibited the actions of AGE-2 and AGE-3. The effects of PGE(2) were mimicked by an E-prostanoid (EP)(2)-receptor agonist, 11,15-O-dimethyl prostaglandin E(2) (ONO-AE1-259-01), and an EP(4) receptor agonist, 16-(3-methoxymethyl)phenyl-omega-tetranor-3,7-dithia prostaglandin E(1) (ONO-AE1-329). An EP(2)-receptor antagonist, 6-isopropoxy-9-oxaxanthene-2-carboxylic acid (AH6809), and an EP(4)-receptor antagonist, (4Z)-7-[(rel-1S,2S,5R)-5-(1,1'-biphenyl-4-yl)methoxy)-2-(4-morpholinyl)-3-oxocyclopentyl]-4-heptenoic acid (AH23848), inhibited the actions of PGE(2). The stimulation of EP(2) and EP(4) receptors is reported to increase cAMP levels. The effects of PGE(2) were reversed by a protein kinase A (PKA) inhibitor, H89, and mimicked by a dibutyryl cAMP and an adenylate cyclase activator, forskolin. These results as a whole indicated that PGE(2) inhibited the actions of AGE-2 and AGE-3 via EP(2)/EP(4) receptors and the cAMP/PKA pathway.

Propofol inhibits cyclo-oxygenase activity in human monocytic THP-1 cells

PURPOSE

Monocytes/macrophages are key players in innate and adaptive immunity. Upon stimulation, they secrete prostanoids, which are produced by cyclooxygenase from arachidonic acid. Prostanoids influence inflammation and immune responses. We investigated the effect of propofol on prostaglandin E(2) and thromboxane B(2) production by the human monocytic cell line THP-1.

METHODS

The THP-1 cells were cultured with lipopolysaccharide (1 microg ml(-1)) in the presence of clinically relevant sedative/anesthetic concentrations of propofol (0-30 microM) for 18 h, and the concentration of prostaglandin E(2) and thromboxane B(2) in culture supernatants was measured using an enzyme immunoassay. Intracellular cyclooxygenase protein expression was measured by flow cytometry. Cyclooxygenase activity was assessed by measuring production of prostaglandin E(2) and thromboxane B(2) by THP-1 cells after arachidonic acid (10 microM) substrate provision.

RESULTS

Propofol decreased the production of prostaglandin E(2) (75.4 +/- 6.4 pg ml(-1) at 0 microM vs. 28.5 +/- 11.2 pg ml(-1) at 30 microM; P < 0.001) and thromboxane B(2) (282.4 +/- 79.2 pg ml(-1) at 0 microM vs. 40.4 +/- 21.7 pg ml(-1) at 30 microM; P < 0.001). The inhibition was not due to the decreased cyclooxygenase protein expression because intracellular staining of this enzyme was not affected by propofol. After arachidonic acid provision, prostaglandin E(2) and thromboxane B(2) production from activated THP-1 cells was significantly (P < 0.001) decreased with propofol, indicating direct suppression of cyclooxygenase activity with propofol.

CONCLUSIONS

Propofol may modulate inflammation via the suppression of cyclooxygenase activity. Through the inhibition of prostanoid production, propofol may enhance immune responses.

NV-52

NV-52, a synthetic flavonoid derivative, is a selective thromboxane synthase (TXS) inhibitor that is being developed as a treatment for inflammatory bowel disease. NV-52 selectively inhibits TXS in vitro in physiological relevant concentrations, causing a reduction in thromboxane B(2) of </= 40% in association with an increase in prostaglandin E(2). NV-52 is effective in suppressing colonic inflammation in a murine model of inflammatory bowel disease. NV-52 has not demonstrated any toxicity in in vitro and animal toxicological studies, and has been administered to normal volunteers in a Phase I clinical trial without detectable adverse effects. NV-52 is well absorbed and a single dose of 400 mg p.o. produced a plasma concentration that is comparable with the concentrations that have been shown to produce significant TXS inhibition in vitro.

Selective COX-2 inhibitors, eicosanoid synthesis and clinical outcomes: a case study of system failure

Elucidation of differences between the active sites of COX-1 and COX-2 allowed the targeted design of the selective COX-2 inhibitors known as coxibs. They were marketed as non-steroidal anti-inflammatory drugs (NSAIDs) that had improved upper gastrointestinal (GI) safety compared with older non-selective NSAIDs such as diclofenac and naproxen. Two GI safety studies conducted with arthritis patients demonstrated that in terms of upper GI safety, celecoxib was not superior to diclofenac (CLASS study) but rofecoxib was superior to naproxen (VIGOR study). However, the VIGOR study revealed also that rofecoxib had increased cardiovascular (CV) risk compared with naproxen. This clinical outcome was supported by the existence of plausible eicosanoid-based biological mechanisms whereby selective COX-2 inhibition could increase CV risk. Nevertheless, the existence of CV risk with rofecoxib was successfully discounted by its pharmaceutical company owner, Merck & Co, with the assistance of specialist opinion leaders and rofecoxib achieved widespread clinical use for 4-5 years. Rofecoxib was withdrawn from the market when several clinical trials in colorectal cancer and post-operative pain revealed increased CV risk with not only rofecoxib, but also coxibs. The commercial success of rofecoxib provides a case-study of failure of the medical journal literature to guide drug usage. Attention to ethical issues may have provided a more useful guide for prescribers.

Modulation of COX-2 expression by statins in human monocytic cells

Macrophage cyclooxygenase-2 (COX-2) plays an important role in prostaglandin E2 and thromboxane A2 production. Statins are inhibitors of HMG CoA (3-Hydroxy-3-methylglutaryl coenzyme A) reductases and cholesterol synthesis, which block the expression of several inflammatory proteins independent of their capacity to lower endogenous cholesterol. In the present study, we investigated the effect of simvastatin and mevastatin on COX-2 induction in human monocytic cell line U937 and analyzed the underlying mechanisms. Pretreatment of U937 cells with simvastatin or mevastatin for 24 h resulted in a significant reduction in the lipopolysaccharide (LPS)-dependent induction of prostaglandin E2, thromboxane A2 synthesis, and COX-2 expression. Mevalonate, the direct metabolite of HMG CoA reductase, and farnesyl pyrophosphate and geranylgeranyl-pyrophosphate, intermediates of the mevalonate pathway, significantly reversed the inhibitory effect of statins on COX-2. An inhibitor of geranylgeranyl transferases, GGTI-286 mimicked the effect of statins on COX-2 expression. Cytonecrotic factor-1 increased LPS-dependent expression of COX-2. Treatment of cells with NSC 23766, an inhibitor of Rac, which we demonstrated to block Rac 2 activation, resulted in an inhibition of the LPS-dependent expression of COX-2. Whereas no effect was obtained with RhoA/C blocker, C3 exoenzyme. Gel retardation experiments and NFkappaB-p65 transcription factor assay showed that simvastatin and NSC 23766 decrease significantly NF-kappaB complex formation. In macrophages, the antiinflammatory effects of statins are mediated in part through the inhibition of COX-2 and prostanoids. Rac GTPase protein is identified as one of the targets of statins in this regulation.

Cyclooxygenase-2 inhibitors and coronary occlusion--exploring dose-response relationships

AIMS

To investigate the relationship between acute coronary syndrome (ACS) and ingested doses of selective cyclooxygenase-2 (COX-2) inhibitors and other nonsteroidal anti-inflammatory drugs (NSAIDs).

METHODS

Case-control study, commenced August 2003. Cases were patients admitted to hospital with ACS (myocardial infarction/unstable angina). Controls were hospital patients admitted for reasons other than acute vascular ischaemia or conditions that are believed to be complications of treatment with COX-2 inhibitors or NSAIDs. Structured interviews were undertaken within 7 days of admission, collecting information on cardiovascular events and risk factors and all ingested drugs, including the doses of COX-2 inhibitors and NSAID consumed in the previous week and month.

RESULTS

An interim analysis of the data was conducted in late 2004 to inform a review of the COX-2 inhibitors by the Australian drug regulatory agency. Between August 2003 and October 2004, we recruited 328 ACS cases and 478 controls. With non-use of COX-2 inhibitors or NSAIDs as the reference the adjusted odds ratios (OR) for ACS were: celecoxib 1.11 (95% confidence interval 0.59, 2.11), rofecoxib 0.63 (0.31, 1.28) and other NSAIDs 0.67 (0.41, 1.09). Among control subjects, median daily ingested doses of celecoxib and rofecoxib were 200 mg and 13.4 mg, respectively. Using these to stratify risk, adjusted ORs for ACS were: 'low' dose (< median) 0.44 (0.19, 1.03); 'high' dose (>/= median) 1.22 (0.67, 2.21). A test for interaction across doses was statistically significant, OR 2.8 (1.0, 7.7), suggesting that at low doses, COX-2 inhibitors may be protective, becoming risk-inducing only at higher doses.

CONCLUSION

The possibility that the gradient of cardiovascular risk with COX-2 inhibitors runs from protective to risk-inducing has biological plausibility and merits further investigation.

Endothelial cell COX-2 expression and activity in hypoxia

The clinical experience with selective cyclooxygenase (COX)-2 inhibitors reveals there are important protective roles for COX-2 in the cardiovascular system. This study examined the response to hypoxia of endothelial cell eicosanoid synthesis with respect to the role of COX-2 and its molecular regulation in hypoxia. Human umbilical vein endothelial cells (HUVEC) were exposed to hypoxia and the effects on COX-2, prostacyclin (PGI(2)) and thromboxane (TXA(2)) synthesis were examined. COX-2 promoter constructs were used to examine the role of Hypoxia Inducible Factors (HIFs) in COX-2 responses to hypoxia. Hypoxia caused an increase in PGI(2) synthesis, but not TXA(2) synthesis. PGI(2), but not TXA(2) synthesis, was absolutely dependent on upregulation of COX-2 by hypoxia. Mutations of transcription factor binding sites in the promoter showed a lack of involvement of NFkappaB in the response to hypoxia, but suggested involvement of HIFs. Transfection of HUVEC with HIF expression vectors increased activity of the promoter construct and increased native COX-2 expression in normoxia. EMSA showed HIF binding in nuclear extracts of hypoxic HUVEC to a region of the COX-2 promoter. The endothelial cell response to hypoxia involves increased production of the anti-thrombotic eicosanoid, PGI(2), which is dependent on COX-2 upregulation by a HIF-mediated process.

Cyclooxygenase inhibitors not inhibit resting lung cancer A549 cell proliferation

Cyclooxygenase (COX) inhibitors were regarded as anticarcinogenic agents for lung cancer at least partly via PGE2; but these were based on cytokin stimulation experiment on A549 cell. In order to clarify whether COX inhibitors directly inhibit A549 cell, three COX inhibitors, NS398 (selective COX-2 inhibitor), SC560 (selective COX-1 inhibitor), and acetyl salicylic acid (ASA, non-selective COX inhibitor), were studied. NS398, and ASA, can inhibit PGE2 generation via COX-2 inhibition. The viability of A549 cell was assayed by MTT. However, without cytokin stimulation, all the three inhibitors (NS398 0.2-20 microM; SC560 1.0-100 nM; ASA 0.01-1.0 mM) were not able to inhibit A549 cell proliferation, in the other way round, NS398 promoted cell growth. And arachidonic acid (AA) and lipopolysaccharide (LPS) did not disturb the property of its growth. These data suggested that without cytokin stimulation, COX and PGE2 may not be the kernel molecules involved in A549 cell proliferation, and COX inhibitors could not inhibit A549 cell growth directly.

Intense Vasoconstriction in Response to Aspirate From Stented Saphenous Vein Aortocoronary Bypass Grafts

OBJECTIVES

We sought to identify soluble vasoconstrictor substances that are released during stent implantation into saphenous vein aortocoronary bypass grafts.

BACKGROUND

Atherosclerotic saphenous vein aortocoronary bypass grafts are particularly vulnerable to plaque rupture. Protection devices prevent particulate debris from being embolized. Additional soluble vasoconstrictor substances possibly also contribute to impaired microvascular perfusion.

METHODS

Peripheral venous blood (VB) and aspirate (AS) were obtained from 14 patients with a significant stenosis in a saphenous vein graft during stent implantation under protection with a distal balloon occlusion device. In five additional patients, arterial blood (AB) was also taken distal to the stented lesion before intervention. Vasomotor substances in VB, AB, and AS plasma were identified in a bioassay of rat mesenteric arteries with intact (+E) and denuded endothelium (-E). Vasoconstriction was normalized to that induced by potassium chloride depolarization (100%).

RESULTS

Venous blood, AB, and AS plasma induced maximum vasoconstriction within six minutes. The AS plasma induced a vasoconstriction of 138 +/- 13% (-E) and 87 +/- 14% (+E); VB, of 70 +/- 14% (-E) and 23 +/- 4% (+E); and AB plasma obtained before intervention, of 49 +/- 9% (-E) and 36 +/- 8% (+E). The vasoconstrictor potency of AS plasma in endothelium-denuded vessels was related to the severity of anginal symptoms, angiographic stenosis severity, plaque volume, and plaque burden as determined by intravascular ultrasound. The AS plasma-induced vasoconstriction was largely attenuated by combined serotonin/5-hydroxytryptamine (5-HT)(2A/2C)- and 5-HT(1A/1B)-receptor blockade and eliminated by additional thromboxane A2 thromboxane-prostanoid (TP)-receptor blockade.

CONCLUSIONS

Stent implantation releases, apart from and in addition to particulate debris, soluble vasoconstrictor substances that possibly contribute to impaired microvascular perfusion.

Diet and rheumatoid arthritis: a review of the literature

INTRODUCTION

Rheumatoid arthritis is a common inflammatory condition. A large number of patients seek alternative or complementary therapies of which diet is an important component. This article reviews the evidence for diet in rheumatoid arthritis along with the associated concept of oral tolerization.

METHODS

References were taken from Medline from 1966 to September 2004. The keywords, rheumatoid arthritis, diet, n-3 fatty acids, vitamins, and oral tolerization, were used.

RESULTS

Randomized controlled trials (RCTs) indicate that dietary supplementation with n-3 fatty acids provides modest symptomatic benefit in groups of patients with rheumatoid arthritis. Epidemiological studies and RCTs show cardiovascular benefits in the broader population and patients with ischemic heart disease. A number of mechanisms through which n-3 fats may reduce inflammation have been identified. In a small number of patients with rheumatoid arthritis, other dietary manipulation such as fasting, vegan, and elimination diets may have some benefit. However, many of these diets are impractical or difficult to sustain long term.

CONCLUSIONS

Dietary manipulation provides a means by which patients can a regain a sense of control over their disease. Dietary n-3 supplementation is practical and can be easily achieved with encapsulated or, less expensively, bottled fish oil.

COX-2 inhibitors as adjunctive therapy in schizophrenia: rationale for use and evidence to date

A better understanding of the human immune system and its complex interactions has resulted in new insights into the pathoaetiological mechanisms of psychiatric disorders. As a result, new treatment options are being explored. Several findings suggest that an imbalanced immune response is involved in the pathophysiology of schizophrenia. COX-2 inhibitors are known to influence the immune system in a way that may redirect this imbalance. Based on these suggestions, the COX-2 inhibitor celecoxib has been tested as a possible adjunctive therapeutic approach in the treatment of schizophrenia. While the first trial using celecoxib as add-on therapy to an atypical antipsychotic showed a significant beneficial effect, recent studies demonstrated that this effect may be limited to patients with recent-onset schizophrenia.