Secretory Phospholipase A2 Inhibitor Research Articles

Design, Synthesis, and Biological Evaluation of Novel Dual Inhibitors of Secretory Phospholipase A2 and Sphingomyelin Synthase

AbstractA novel series of eight SMS and sPLA2 dual inhibitors containing indole and α‐amino cyanide fragments of different length and substitution position was synthesized and evaluated by three different in vitro assays. Biological evaluation showed that all compounds provided inhibitory effects against SMS (about 50% inhibition at 100 µmol/L) and sPLA2 (14–32 µmol/L). All the compounds had the SMS activity better than the positive control compound D609 in SMS2 homogenate, with compounds 5b and 5e ideal for liver homogenate and SMS2 high expression cell homogenate, respectively.

MiR-203 Regulates Nociceptive Sensitization after Incision by Controlling Phospholipase A2 Activating Protein Expression

After incision keratinocytes in the epidermis become activated to produce a range of pain-related mediators. microRNA 203 (miR-203) is known to be involved in keratinocyte growth, differentiation, and skin inflammation. We hypothesized that one or more of these mediators might be under the control of miR-203. The expression of miR-203 and its target gene, phospholipase A2 activating protein (PLAA), were examined after hind paw incision in mice. We investigated the local effect of intraplantar PLAA peptide injection in normal mice and the effects of a selective secretory phospholipase A2 inhibitor (HK064) on PLAA or incision-induced mechanical allodynia. Last, we investigated the role of substance P signaling in regulating miR-203 and PLAA expression in vitro and in vivo. Levels of miR-203 were strongly down-regulated in keratinocytes after incision. Informatics-based approaches identified PLAA as a likely candidate for regulation by miR-203. PLAA caused mechanical allodynia and conditioned place aversion but not thermal sensitization. HK064 reduced mechanical allodynia after incision and after intraplantar injection of PLAA. Using preprotachykinin gene knockout mice or with neurokinin-1 selective antagonist LY303870 treatment, we observed that substance P-mediated signaling was also required for miR-203 and PLAA regulation after incision. Finally, using the rat epidermal keratinocyte cell line, we observed that a miR-203 mimic molecule could block the substance P-induced increase in PLAA expression observed under control conditions. miR-203 may regulate expression of the novel nociceptive mediator PLAA after incision. Furthermore, the regulation of miR-203 and PLAA levels is reliant upon intact substance P signaling.

Response to Letter Regarding Article, “The sPLA 2 Inhibition to Decrease Enzyme Release After Percutaneous Coronary Intervention (SPIDER-PCI) Trial”

We thank Dr Krijnen and colleagues for their interest in our sPLA2 Inhibition to Decrease Enzyme Release after Percutaneous Coronary Intervention (SPIDER-PCI) study, the results of which were not suggestive of any evidence of a protective benefit of varespladib, an inhibitor of secretory phospholipase A2 (sPLA2), in reducing myocardial injury sustained after elective percutaneous coronary intervention (PCI).1 The hypothesis that varespladib might reduce myocardial injury associated with PCI arose from observations that nonemergent PCI is associated with a marked increase in blood sPLA2 levels.2 Krijnen et al suggest that our patient cohort was unsuitable for the study of the hypothesis that sPLA2 is involved in PCI-related cardiac inflammatory injury. We agree, and this was not our hypothesis. Rather, we set out to study whether or not sPLA2 inhibition would reduce the myocardial injury frequently observed after PCI in a stable elective PCI population. The observational …

Comparative efficacy of a secretory phospholipase A2 inhibitor with conventional anti-inflammatory agents in a rat model of antigen-induced arthritis

IntroductionPreviously, secretory phospholipase A2 (sPLA2) inhibition has been used as an adjunct to conventional rheumatoid arthritis therapy in human clinical trials without significant improvement of arthritic pathology. In this study, we compared the efficacy of a potent and orally active group IIa secretory phospholipase A2 inhibitor (sPLA2I) to conventional anti-arthritic agents; infliximab, leflunomide and prednisolone, in a rat model of antigen-induced arthritis.MethodsInitially, to establish efficacy and dose-response, rats were orally dosed with the sPLA2I (1 and 5 mg/kg) two days prior to arthritis induction, and then daily throughout the 14-day study period. In the second trial, rats were orally dosed with the sPLA2I (5 and 10 mg/kg/day) beginning two days after the induction of arthritis, at the peak of joint swelling. Separate groups of rats were also dosed with the tumour necrosis factor-alpha (TNF-α) inhibitor infliximab (single 3 mg/kg i.v. injection), leflunomide (10 mg/kg/day, oral) or prednisolone (1 mg/kg/day, oral) at this same time point and used as comparative treatments.ResultsIn the pathology prevention trial, both 1 and 5 mg/kg dose groups of sPLA2I demonstrated a significant reduction in joint swelling and gait disturbances; however, only the higher 5 mg/kg dose resulted in significantly reduced histopathology scores. In the post-induction trial, rats dosed with sPLA2I showed a significant improvement in joint swelling and gait scoring, whereas none of the conventional therapeutics achieved a significant decrease in both of these two disease markers. Histopathological scoring at the end-point of the study demonstrated significantly reduced median scores in rats treated with 10 mg/kg sPLA2I and leflunomide.ConclusionsThe results from this study suggest a pathogenic role for sPLA2 enzymes in this model of arthritis in rats, and the potential clinical utility of sPLA2 inhibition as a safer, and more effective, alternative to conventional anti-arthritic therapeutics.

Synthesis of N-(Trifluoromethyl-2-pyridinyl)arenesulfonamides as an Inhibitor of Secretory Phospholipase A2

A series of N-(trifluoromethyl-2-pyridinyl)alkane- and arenesulfonamides 2-5 have been synthesized by the substitution reaction of 2-chloro(trifluoromethyl)pyridines 6 with alkane- and arenesulfonamides 7. Their inhibitory activities against secretory phospholipase A₂ of porcine pancreas were examined and the analog N-[4,5-bis(trifluoromethyl)-2-pyridinyl]-4-trifluoromethylbenzenesulfonamide 4i was shown to have the highest inhibitory activity, with an IC(50) value of 0.58 mM.

Inhibition of Untransformed Prostaglandin H2 Production and Stretch-Induced Contraction of Rabbit Pulmonary Arteries by Indoxam, a Selective Secretory Phospholipase A2 Inhibitor

Involvement of secretory phospholipase A2 (sPLA2) in the stretch-induced production of untransformed prostaglandin H2 (PGH2) in the endothelium of rabbit pulmonary arteries was investigated. The stretch-induced contraction was significantly inhibited by indoxam, a selective inhibitor for sPLA2, and NS-398, a selective inhibitor for cyclooxygenase-2 (COX-2). Indoxam inhibited the RGD-sensitive-integrin–independent production of untransformed PGH2, but did not affect the RGD-sensitive-integrin–dependent production of thromboxane A2 (TXA2). These results suggest that the stretch-induced contraction and untransformed PGH2 production was mediated by sPLA2–COX-2 pathway, making it a new possible target for pharmacological intervention of pulmonary artery contractility.

Phospholipase A2 inhibition and atherosclerotic vascular disease: prospects for targeting secretory and lipoprotein-associated phospholipase A2 enzymes

Selective inhibitors of secretory phospholipase A2 and lipoprotein-associated phospholipase A2 are potential candidates for reducing recurrent cardiovascular events in patients with established coronary heart disease (CHD). With the active enrollment of CHD patients into phase III clinical trials with both classes of inhibitors, this article reviews the available experimental animal and human trial evidence that provides the rationale for the development of the phospholipase A2 inhibitors varespladib methyl and darapladib as preventive therapy. Recently completed experimental animal studies, human biomarker data, and vascular imaging studies provide support for proceeding with clinical outcome trials secretory phospholipase A2 and lipoprotein-associated phospholipase A2 inhibition. Both secretory phospholipase A2 and lipoprotein-associated phospholipase A2 inhibitors hold promise for the reduction of recurrent cardiovascular events in patients treated with current standards of care. The completion of the ongoing clinical event trials has the potential to provide a new dimension to secondary preventive therapy.

Varespladib: targeting the inflammatory face of atherosclerosis

This editorial refers to ‘Randomized trial of an inhibitor of secretory phospholipase A2 on atherogenic lipoprotein subclasses in statin-treated patients with coronary heart disease’, by R.S. Rosenson et al., doi:10.1093/eurheartj/ehq374 Atherosclerosis is a complex disease and in its pathogenesis depends on the interaction between lipoproteins and inflammatory mediators.1 This interaction orchestrates the progression of atherosclerosis from its earliest stage when oxidized lipoproteins and leucocytes penetrate dysfunctional endothelium and enter the subendothelial space, right until the end of the process when the plaque becomes unstable and ruptures, leading to a clinical event. Whereas our pharmacological armatorium that targets the lipid component of the risk factor spectrum has been tremendously succesful with the clinical introduction of statins in the middle of the 1990s, drugs that target the inflammatory face of atherosclerosis have thus far been scarce. Among the wide range of chemokines, adhesion molecules, and pro-oxidative substances that affect macrophage recruitment into the arterial wall, members of the phospholipase A2 (PLA2) family have received considerable attention since their purification from human plasma lipoproteins in 1987.2 PLA2s are small and relatively stable ubiquitous enzymes that hydrolyse the sn -2-acyl bond of phospholipids in cell membranes as well as in lipoproteins. This enzymatic activity yields non-esterified fatty acids and lysophospholipids, which are precursors of various proinflammatory mediators including leukotrienes, eicosanoids, prostaglandins, and platelet-activating factors ( Figure 1A ).3 In addition, both circulating and lipoprotein-bound PLA2s play a role in lipoprotein remodelling by high-affinity binding to specific domains on LDLs and apolipoprotein B. Such modified or oxidized LDL particles bind with higher affinity to endothelial proteoglycans, facilitating the penetration of these atherogenic particles into the subendothelial matrix where they accumulate and trigger additional proinflammatory cascades. The recent large-scale meta-analysis of genome-wide association studies for plasma lipids …

Randomized trial of an inhibitor of secretory phospholipase A2 on atherogenic lipoprotein subclasses in statin-treated patients with coronary heart disease

To investigate the effects of secretory phospholipase A2 (sPLA(2)) inhibition on plasma lipoproteins. Secretory phospholipase A2 isoenzymes promote atherosclerosis by mechanisms that include lipoprotein modification, retention, and oxidation. Phospholipase Levels And Serological Markers of Atherosclerosis II (PLASMA II) is a Phase II, randomized, double-blind, placebo-controlled parallel-arm study of two once-daily doses of the novel sPLA(2) inhibitor, 1-H-indole-3-glyoxamide or varespladib methyl (Anthera Pharmaceuticals, Hayward, CA, USA). One hundred and thirty-five stable coronary heart disease patients were treated with either varespladib methyl 250 mg once daily, varespladib methyl 500 mg once daily, or placebo for 8 weeks. Varespladib methyl treatment resulted in statistically significant dose-dependent reductions that were different from placebo in sPLA(2) concentration, low-density lipoprotein (LDL) cholesterol, and non-high-density lipoprotein (HDL) cholesterol. When compared with placebo, varespladib methyl 500 mg once daily reduced LDL cholesterol by 15% (P < 0.001), non-HDL cholesterol by 15% (P < 0.001), total very LDL (VLDL) particle concentration by 14% (P = 0.022), and small VLDL particle concentration by 24% (P = 0.030). Relative to baseline, varespladib methyl 500 mg once daily reduced total LDL particle concentration (7%, P = 0.002) and small LDL particle concentration (11%, P = 0.014). Reductions in atherogenic lipoproteins suggest that varespladib methyl 500 mg once daily may be an effective anti-atherosclerotic agent. Trial registered at ClinicalTrials.gov, identifier: NCT00525954.

Quercetin as an inhibitor of snake venom secretory phospholipase A2

As polyphenolic compounds isolated from plants extracts, flavonoids have been applied to various pharmaceutical uses in recent decades due to their anti-inflammatory, cancer preventive, and cardiovascular protective activities. In this study, we evaluated the effects of the flavonoid quercetin on Crotalus durissus terrificus secretory phospholipase A2 (sPLA2), an important protein involved in the release of arachidonic acid from phospholipid membranes. The protein was chemically modified by treatment with quercetin, which resulted in modifications in the secondary structure as evidenced through circular dichroism. In addition, quercetin was able to inhibit the enzymatic activity and some pharmacological activities of sPLA2, including its antibacterial activity, its ability to induce platelet aggregation, and its myotoxicity by approximately 40%, but was not able to reduce the inflammatory and neurotoxic activities of sPLA2. These results suggest the existence of two pharmacological sites in the protein, one that is correlated with the enzymatic site and another that is distinct from it. We also performed molecular docking to better understand the possible interactions between quercetin and sPLA2. Our docking data showed the existence of hydrogen-bonded, polar interactions and hydrophobic interactions, suggesting that other flavonoids with similar structures could bind to sPLA2. Further research is warranted to investigate the potential use of flavonoids as sPLA2 inhibitors.

Chemical modification of ascorbic acid and evaluation of its lipophilic derivatives as inhibitors of secretory phospholipase A2 with anti-inflammatory activity

The halo 6-fatty acid esters of L-ascorbic acid 3a, 3b and 6-fatty acid esters of L-ascorbic acid 5a-g were achieved from L-ascorbic acid 1. Compounds 3a, 3b and 5a-g were evaluated for anti-oxidant, anti-lipid peroxidation, and secretory phospholipase A(2) (sPLA(2)) inhibition in vitro, and sPLA(2) induced mouse paw edema. All the derivatives retained their anti-oxidant property compared to ascorbic acid at 6 × 10(-4)M and are good inhibitors of lipid peroxidation at 1 mg ml(-1) as evaluated by 2, 2-Diphenyl-1-picrylhydrazyl radical and thio-barbituric acid methods, respectively. Compounds 5e and 5f significantly inhibited purified group I sPLA(2) from Naja naja and group II sPLA(2) from Vipera russelli, human synovial fluid and human pleural fluid with IC(50) value ranging from 64 ± 1.95 to 82 ± 1.3 and 48 ± 2.27 to 61 ± 2.23 μM, respectively. The compounds 5e and 5f also showed varying degree of potency in neutralizing indirect hemolytic activity of sPLA(2) at 50 μM concentration, and sPLA(2) induced mouse paw edema at the dose 3 mg/kg. Further docking studies also confirmed that compounds 5e and 5f have maximum interaction with increasing negative energy value. Single molecule possessing both anti-oxidant and anti-inflammatory activities is of great therapeutic significance in inflammatory disorders.

Inhibition of secretory phospholipase A2 activity attenuates lipopolysaccharide-induced acute lung injury in a mouse model

ABSTRACTThis study evaluated the hypothesis that LY374388, an inhibitor of secretory phospholipase A2 (sPLA2) activity, may exert a protective effect on lipopolysaccharide (LPS)-induced acute lung injury in male C57BL/6J mice. Intratracheal administration of LPS increased histopathological changes in lung tissue, lung wet to dry ratios, and the bronchoalveolar lavage fluid levels of neutrophil numbers, sPLA2 activity, leukotriene B4, and thromboxane B2. However, a simultaneous intraperitoneal treatment with LY374388 significantly attenuated these LPS-induced changes. Thus, inhibition of sPLA2 activity significantly attenuated the acute lung injury induced by LPS. sPLA2 played an important role in the pathogenesis of LPS-induced acute lung injury in mice.

Nonantibiotic Properties of Tetracyclines: Structural Basis for Inhibition of Secretory Phospholipase A2

Secretory phospholipase A2 is involved in inflammatory processes and was previously shown to be inhibited by lipophilic tetracyclines such as minocycline (minoTc) and doxycycline. Lipophilic tetracyclines might be a new lead compound for the design of specific inhibitors of secretory phospholipase A2, which play a crucial role in inflammatory processes. Our X-ray crystal structure analysis at 1.65 Å resolution of the minoTc complex of phospholipase A2 (PLA2) of the Indian cobra (Naja naja naja) is the first example of nonantibiotic tetracycline interactions with a protein. MinoTc interferes with the conformation of the active-site Ca2+-binding loop, preventing Ca2+ binding, and shields the active site from substrate entrance, resulting in inhibition of the enzyme. MinoTc binding to PLA2 is dominated by hydrophobic interactions quite different from antibiotic recognition of tetracyclines by proteins or the ribosome. The affinity of minoTc for PLA2 was determined by surface plasmon resonance, resulting in a dissociation constant Kd=1.8×10−4 M.

Genistein, a potent inhibitor of secretory phospholipase A2: a new insight in down regulation of inflammation

Some of the legumes, spices and medicinal herbs rich in genistein are known for their anti-inflammatory properties. Anti-inflammatory property of these herbs is determined by subjecting secretory phospholipase A(2) (sPLA(2)) inhibition, a key enzyme in the inflammatory reactions by genistein. Genistein was assessed for inhibition of sPLA(2) activity using (14)C-oleate radiolabelled Escherichia coli membrane as substrate. The enzyme-inhibitor interaction was established by intrinsic fluorescence and circular dichroism studies. The in vivo anti-inflammatory activity was tested by injecting sPLA(2), Vipera russelli venom phospholipase-V (VRV-PL-V) with different concentrations of genistein in the range of 3-21 muM into intra plantar surface of right hind footpad of mice. Systemic effect was tested by administering the genistein (21 muM) i.p. 30 min before and immediately after sPLA(2) injection. Genistein inhibited sPLA(2) enzymes of inflammatory exudates (human synovial fluid and human pleural fluid) and snake venoms (VRV-PL-V and Naja naja phospholipase-I) in a concentration dependent manner with IC(50) values ranging from 5.75 to 11.75 muM. Increasing the calcium (Ca(2+)) concentration from 2.5 to 15 mM and substrate concentration up to 120 nM did not alter the level of inhibition. Genistein alters the intrinsic fluorescence intensity and shown apparent shift in far ultra violet-circular dichroism spectra of VRV-PL-V, indicating the direct interaction with enzyme. Genistein also inhibited the VRV-PL-V induced mouse paw oedema in a concentration dependent manner. The genistein at 21 muM concentration administered immediately after the VRV-PL-V injection, effectively neutralized the oedema inducing activity. Genistein inhibited sPLA(2) activity of both inflammatory exudates and snake venoms in a concentration dependent manner and sPLA(2) induced mouse paw oedema. The study partially explains the observed anti-inflammatory property of several medicinal herbs which containing genistein.

The use of live‐animal micro‐computed tomography to determine the effect of a novel phospholipase A2 inhibitor on alveolar bone loss in an in vivo mouse model of periodontitis

Live-animal micro-computed tomography is a new and promising technique that can be used to quantify changes in bone volume for periodontal disease models. The major aim of this study was to develop the methodology of live-animal micro-computed tomography and to determine the effect of a novel secretory phospholipase A2 inhibitor on alveolar bone loss. Periodontitis was induced in mice by oral infection with Porphyromonas gingivalis over a period of 13 wk, and live-animal micro-computed tomography scans were taken at different time-points to determine bone volume changes with disease progression. This enabled conclusions to be made as to when treatment was most likely to be effective. In addition, the model was used to investigate a novel drug, the secretory phospholipase A2 inhibitor, KHO64, and its potential ability to inhibit osteoclast bone resorption and treat periodontitis. The results from live-animal micro-computed tomography scans revealed greater, statistically significant, bone volume loss in diseased mice compared with normal mice (p < 0.05). This corresponded to a larger area from the cemento-enamel junction to the alveolar bone crest, as assessed by stereo imaging (p < 0.001). These techniques can therefore detect and quantify alveolar bone loss. Both methods revealed that KHO64 had no significant effect on the volume of bone resorption. Live-animal micro-computed tomography is a robust, reproducible technique that clearly demonstrates significant time-dependent changes in alveolar bone volume in a small-animal model of periodontitis.

Synthesis and Evaluation of Benzophenone Oximes Derivatized with Sydnone as Inhibitors of Secretory Phospholipase A2 with Anti-inflammatory Activity

A series of benzophenone oximes appended with sydnone (3a--h) bearing different substituents on aroyl moiety were synthesized to evaluate in vivo and in vitro for their inhibitory activity against purified phospholipase A2 (PLA2) enzymes from snake venom and human inflammatory pleural and ascites fluid. In vivo and in vitro inhibition studies were carried out against PLA2 with respect to the modification of the pharmacophore (substituent) to analyze the specificity for PLA2. The substituent at the aroyl ring was responsible for enhancing the inhibition towards PLA2 enzymes. Most of the newly synthesized compounds inhibit the purified PLA2 enzyme, and the inhibition was more in hydrophobic and aromatic substituents and less when no such substituents were present. The inhibitory effect of the compounds appeared to be due to the direct interaction of compounds with the enzyme. Inhibition is substrate dependent, and the inhibition competes with the substrate for the same binding site of the enzyme. The most active interacting compound 3h from in vitro inhibition of PLA2 activity showed similar potency in the in vivo neutralization of PLA2 induced mouse paw edema and hemolytic activity. Thus, the in vitro inhibition correlated well with the in vivo inhibition and hence the reported derivatives are therapeutically important anti-inflammatory drugs.

P.192 Impacted third molar extraction: methylprednisolone or nimesulide

The pharmacological nature of nicotine-induced contraction in the rat basilar artery is poorly understood. The purpose of this study was to investigate the endothelium dependency and involvement of arachidonic acid metabolites in nicotine-induced contraction in the rat basilar artery. The rat basilar artery was removed from the brain and cut into a spiral preparation. Nicotine (3 × 10− 5 to 10− 2 M) induced the concentration-dependent contraction in the rat basilar artery, and the maximal contraction was obtained at 3 × 10− 3 M. The contraction induced by nicotine (3 × 10− 3 M) was significantly attenuated by the presence of saponin (0.05 mg/ml, 15 min). Phospholipase C (PLC) inhibitors (NCDC and U-73122), calcium-independent phospholipase A2 (iPLA2) inhibitor (BEL), cyclooxygenase-2 (COX-2) inhibitors (nimesulide, L-745,337 and celecoxib), and a 5-lipoxygenase (5-LOX) inhibitor (ZM-230487) concentration-dependently attenuated the nicotine-induced contraction. A cytosolic phospholipase A2 (cPLA2) inhibitor (AACOCF3), secretory phospholipase A2 (sPLA2) inhibitor (indoxam), and cyclooxygenase-1 (COX-1) inhibitors (flurbiprofen and ketoprofen) did not affect the nicotine-induced contraction. From these results, it was suggested that nicotine-induced contraction in the rat basilar artery is endothelium-dependent and is due to arachidonic acid metabolites.

A‐002, a secretory phospholipase A2 inhibitor, reduces cholesterol accumulation in aorta and aortic cytokines in guinea pigs

Secretory phospholipase A2 enzymes (sPLA2) are involved with the generation of proinflammatory molecules such as leukotrienes and prostaglandins and are associated with atherosclerotic plaques. In this study we tested the effects of an sPLA2 inhibitor (A‐002) on aortic inflammatory cytokines and aortic lipid accumulation in a guinea pig atherosclerosis model. For this purpose, 24 male Hartley guinea pigs (12 per group) were fed a diet containing 0.25% dietary cholesterol to induce atherosclerosis, for 3 months. Animals were randomized into placebo (PL) or treated (A‐002) group, and gavaged daily either with vehicle (10% acacia, PL) or A‐002 (150 mg/kg/d, A‐002). At the end of 12 weeks, guinea pigs were sacrificed and blood was collected to measure plasma lipids and lipoprotein subfractions. The aorta was harvested for histological evaluation, measurement of inflammatory cytokines and lipid accumulation. Aortic cytokines including Interleukin (IL)‐2, IL‐10, IL‐12 and GMSCF measured by use of antibodies and Luminex technique were significantly lower (p &lt; 0.05) in the A‐002 group. In addition, the A‐002 group had 26.5% lower cholesterol accumulation in the aorta (p &lt; 0.05), but not in plasma, in association with a reduction in atherosclerotic lesion content in the aortic sinus. From these studies we conclude that A‐002 was effective in reducing atherosclerosis, as indicated by reductions in aortic cholesterol content, inflammatory cytokines and lesion content. [Study supported by Anthera Pharmaceuticals, Inc., San Mateo, CA].

Venous and arterial thromboembolism in severe sepsis

The burden of thromboembolism (TE) in severe sepsis is largely unknown. We assessed the prevalence of venous and arterial TE in patients with severe sepsis over a four-week period. We performed a retrospective analysis of a pooled database of three randomized, placebo-controlled trials of two novel pharmacological agents for the treatment of severe sepsis, drotrecogin alfa (activated) (DrotAA) and secretory phospholipase A2 inhibitor (sPLA(2)I). The study was conducted at intensive care units of the participating institutions. A total of 2,649 patients with known or suspected infection and sepsis-associated acute organ dysfunction were enrolled in the three trials and were assigned to treatment groups (DrotAA=850; sPLA2I=578; placebo=1221). The database was queried for venous and arterial TE, using investigator reports of serious adverse events. Eighty-four of 2,649 patients (3.2%; 95% confidence interval, 2.5% to 3.9%) developed at least one thromboembolic event over 28 days. Nearly three-quarters of episodes were atheroembolic (n=62); 25% involved the deep venous system (n=25). Ischemic stroke (n=30) and venous thromboembolism (n=25) each occurred in about 1% of patients. Ischemic stroke and acute coronary syndrome had a higher peak incidence during the first five days compared to venous TE onset, which was more constant over the 28-day period. Subgroup analysis by pooled treatment groups yielded TE rates of 2.0% (DrotAA), 3.5% (placebo), and 4.0% (sPLA2I), respectively. Clinically manifest TE occurred in about 3% of severe sepsis patients treated in the intensive care unit over a 28-day period. Arterial TE may be more common than previously recognized. More accurate estimates of TE prevalence and relationship to sepsis await future studies.

EDITORIAL

We are delighted to welcome five new members to our team of Associate Editors. Dr David Armstrong from Melbourne, Australia is an expert in cystic fibrosis, paediatric lung diseases and sleep. Dr Andreas Diacon works in Cape Town, South Africa and his interests are tuberculosis, pleural disease and bronchoscopy. Professor Martin Kolb is a chest physician specializing in pulmonary fibrosis research and works at McMaster University in Hamilton (Ontario), Canada. Professor Helen Reddel from Sydney, Australia conducts research focused on a better understanding of the mechanisms and outcomes of asthma treatment. Professor Jeff Swigris from Denver (Colorado), USA specializes in pulmonary fibrosis and lung disease, with a particular interest in connective tissue disease-related interstitial lung disease. We look forward to their contribution to the Journal. We are also very pleased to announce that Professor Michael Abramson has recently joined the Journal as Honorary Epidemiologist-Statistician. Professor Abramson works at Monash University in Melbourne, Australia and has specialized in the clinical epidemiology of asthma and COPD, including genetic and environmental risk factors such as air pollution and occupation, and the role of spirometry in managing these conditions. Professor Abramson's role will be to assist Associate Editors in assessing the validity of specific study designs and/or the statistical methods used. We look forward to his contribution to the Journal which will ensure a higher standard for manuscripts accepted for publication in Respirology. This issue marks the second of our review articles inspired by lectures presented by the presidents of five major respiratory societies (APSR, ERS, ACCP, ALAT and ATS) at the last APSR conference in Kyoto, Japan. This second review entitled ‘Nosocomial Acinetobacter Pneumonia’ has been written by Professor Carlos Luna, President of the ALAT, and his colleague Dr Patricia Aruj (pp. 787–791). In their review, Professor Luna and Dr Aruj discuss the microbiology and epidemiology of Acinetobacter, the risk factors involved with Acinetobacter infections and treatment options. I am sure this review will be of great interest to our readers. A highlight of this issue is the article by Dr Ning and Professor Wang entitled ‘Role of Rel A and IkappaB of nuclear factor κB in the release of interleukin-8 by cyclic mechanical strain in human alveolar type II epithelial cells A549’ (pp. 792–798). These authors report that cyclic mechanical stretch, such as mechanical ventilation, can activate Rel A translocation and IkBα degradation, inducing the secretion of pro-inflammatory cytokines such as IL-8, which may ultimately lead to ventilator-associated lung injury. This study provides insights into the potential for new preventative therapies for ARDS and ventilator-associated lung injury. The article by Dr Trejo and colleagues ‘Beneficial effects of hydrocortisone and papaverine on a model of pulmonary embolism induced by autologous blood-clots in isolated and perfused rabbit lungs’ (pp. 799–806) investigates the effect of an anti-inflammatory drug (hydrocortisone) and a vasodilator (papaverine) on a model of pulmonary embolism induced by autologous blood-clots in isolated and perfused rabbit lungs, and suggests that vasodilatation and anti-inflammatory therapies may be useful in treating pulmonary embolism. If reproducible in humans this could be an important new direction for treating pulmonary embolism. Another highlight in this issue is the article by Dr Aoki-Nagase and colleagues entitled ‘Calcitonin gene-related peptide mediates acid-induced lung injury in mice’ (pp. 807–813). These authors observed attenuated acid-induced injury, oedema and respiratory failure in mice with disrupted calcitonin gene-related peptide genes, suggesting a role for these peptides in the pathogenesis of acute lung injury caused by acid aspiration. In the article entitled ‘Surfactant degradation activity in bronchoalveolar lavage fluid from guinea pigs challenged with antigen’ (pp. 828–833), Dr Abo and colleagues confirmed the degradation of surfactant in bronchoalveolar lavage fluid from guinea pigs challenged with inhaled antigen. They also showed that this degradation can be partially suppressed by a secretory phospholipase A2 inhibitor, suggesting potential new treatment options for bronchial asthma. The case–control study by Professor Fei Xu and colleagues ‘Better understanding the influence of cigarette smoking and indoor air pollution on COPD: A case–control study in mainland China’ (pp. 891–897) investigates to what extent cigarette smoking and exposure to indoor air pollution is associated with COPD in a mainland Chinese population. Their findings support the need for public health initiatives that discourage cigarette smoking, especially among women. Finally, a technical report by Dr Schmid and colleagues ‘Design and validation of interpretative strategy for cardiopulmonary exercise tests’ (pp. 916–923) describes the development of a strategy for the interpretation of cardiopulmonary exercise tests with a diagnostic precision that approaches the consensus of two experts in the field. This strategy can improve the consistency of interpretation of cardiopulmonary exercise tests in a pulmonary centre with physicians who have varying degrees of expertise. I hope you enjoy this issue of Respirology.