TMEM16F forms a Ca2+-activated cation channel required for lipid scrambling in platelets during blood coagulation.

Collapse of membrane lipid asymmetry is a hallmark of blood coagulation. TMEM16F of the TMEM16 family that includes TMEM16A/B Ca(2+)-activated Cl(-) channels (CaCCs) is linked to Scott syndrome with deficient Ca(2+)-dependent lipid scrambling. We generated TMEM16F knockout mice that exhibit bleeding defects and protection in an arterial thrombosis model associated with platelet deficiency in Ca(2+)-dependent phosphatidylserine exposure and procoagulant activity and lack a Ca(2+)-activated cation current in the platelet precursor megakaryocytes. Heterologous expression of TMEM16F generates a small-conductance Ca(2+)-activated nonselective cation (SCAN) current with subpicosiemens single-channel conductance rather than a CaCC. TMEM16F-SCAN channels permeate both monovalent and divalent cations, including Ca(2+), and exhibit synergistic gating by Ca(2+) and voltage. We further pinpointed a residue in the putative pore region important for the cation versus anion selectivity of TMEM16F-SCAN and TMEM16A-CaCC channels. This study thus identifies a Ca(2+)-activated channel permeable to Ca(2+) and critical for Ca(2+)-dependent scramblase activity during blood coagulation. PAPERFLICK:

Visualizing Dynamics of Cell Signaling In Vivo with a Phase Separation-Based Kinase Reporter.

Visualizing dynamics of kinase activity in living animals is essential for mechanistic understanding of cell and developmental biology. We describe GFP-based kinase reporters that phase-separate upon kinase activation via multivalent protein-protein interactions, forming intensively fluorescent droplets. Called SPARK (separation of phases-based activity reporter of kinase), these reporters have large dynamic range (fluorescence change), high brightness, fast kinetics, and are reversible. The SPARK-based protein kinase A (PKA) reporter reveals oscillatory dynamics of PKA activities upon G protein-coupled receptor activation. The SPARK-based extracellular signal-regulated kinase (ERK) reporter unveils transient dynamics of ERK activity during tracheal metamorphosis in live Drosophila. Because of intensive brightness and simple signal pattern, SPARKs allow easy examination of kinase signaling in living animals in a qualitative way. The modular design of SPARK will facilitate development of reporters of other kinases.

The sphingosine 1-phosphate receptor S1P2 maintains the homeostasis of germinal center B cells and promotes niche confinement.

Mice deficient in sphingosine 1-phosphate receptor type 2 (S1P(2)) develop diffuse large B cell lymphoma. However, the role of S1P(2) in normal germinal center (GC) physiology is unknown. Here we show that S1P(2)-deficient GC B cells outgrew their wild-type counterparts in chronically established GCs. We found that antagonism of the kinase Akt mediated by S1P(2) and its downstream mediators Gα(12), Gα(13) and p115RhoGEF regulated cell viability and was required for growth control in chronically proliferating GCs. Moreover, S1P(2) inhibited GC B cell responses to follicular chemoattractants and helped confine cells to the GC. In addition, S1P(2) overexpression promoted the centering of activated B cells in the follicle. We suggest that by inhibiting Akt activation and migration, S1P(2) helps restrict GC B cell survival and localization to an S1P-low niche at the follicle center.

Anatomical profiling of G protein-coupled receptor expression.

G protein-coupled receptors (GPCRs) comprise the largest family of transmembrane signaling molecules and regulate a host of physiological and disease processes. To better understand the functions of GPCRs in vivo, we quantified transcript levels of 353 nonodorant GPCRs in 41 adult mouse tissues. Cluster analysis placed many GPCRs into anticipated anatomical and functional groups and predicted previously unidentified roles for less-studied receptors. From one such prediction, we showed that the Gpr91 ligand succinate can regulate lipolysis in white adipose tissue, suggesting that signaling by this citric acid cycle intermediate may regulate energy homeostasis. We also showed that pairwise analysis of GPCR expression across tissues may help predict drug side effects. This resource will aid studies to understand GPCR function in vivo and may assist in the identification of therapeutic targets.

The lung is a site of platelet biogenesis and a reservoir for haematopoietic progenitors.

Platelets are critical for haemostasis, thrombosis, and inflammatory responses, but the events that lead to mature platelet production remain incompletely understood. The bone marrow has been proposed to be a major site of platelet production, although there is indirect evidence that the lungs might also contribute to platelet biogenesis. Here, by directly imaging the lung microcirculation in mice, we show that a large number of megakaryocytes circulate through the lungs, where they dynamically release platelets. Megakaryocytes that release platelets in the lungs originate from extrapulmonary sites such as the bone marrow; we observed large megakaryocytes migrating out of the bone marrow space. The contribution of the lungs to platelet biogenesis is substantial, accounting for approximately 50% of total platelet production or 10 million platelets per hour. Furthermore, we identified populations of mature and immature megakaryocytes along with haematopoietic progenitors in the extravascular spaces of the lungs. Under conditions of thrombocytopenia and relative stem cell deficiency in the bone marrow, these progenitors can migrate out of the lungs, repopulate the bone marrow, completely reconstitute blood platelet counts, and contribute to multiple haematopoietic lineages. These results identify the lungs as a primary site of terminal platelet production and an organ with considerable haematopoietic potential.

Designing a Green Fluorogenic Protease Reporter by Flipping a Beta Strand of GFP for Imaging Apoptosis in Animals.

A family of proteases called caspases mediate apoptosis signaling in animals. We report a GFP-based fluorogenic protease reporter, dubbed "FlipGFP", by flipping a beta strand of the GFP. Upon protease activation and cleavage, the beta strand is restored, leading to reconstitution of the GFP and fluorescence. FlipGFP-based TEV protease reporter achieves 100-fold fluorescence change. A FlipGFP-based executioner caspase reporter visualized apoptosis in live zebrafish embryos with spatiotemporal resolution. FlipGFP also visualized apoptotic cells in the midgut of Drosophila. Thus, the FlipGFP-based caspase reporter will be useful for monitoring apoptosis during animal development and for designing reporters of proteases beyond caspases. The design strategy can be further applied to a red fluorescent protein for engineering a red fluorogenic protease reporter.

Podoplanin maintains high endothelial venule integrity by interacting with platelet CLEC-2.

Circulating lymphocytes continuously enter lymph nodes for immune surveillance through specialized blood vessels named high endothelial venules, a process that increases markedly during immune responses. How high endothelial venules (HEVs) permit lymphocyte transmigration while maintaining vascular integrity is unknown. Here we report a role for the transmembrane O-glycoprotein podoplanin (PDPN, also known as gp38 and T1α) in maintaining HEV barrier function. Mice with postnatal deletion of Pdpn lost HEV integrity and exhibited spontaneous bleeding in mucosal lymph nodes, and bleeding in the draining peripheral lymph nodes after immunization. Blocking lymphocyte homing rescued bleeding, indicating that PDPN is required to protect the barrier function of HEVs during lymphocyte trafficking. Further analyses demonstrated that PDPN expressed on fibroblastic reticular cells, which surround HEVs, functions as an activating ligand for platelet C-type lectin-like receptor 2 (CLEC-2, also known as CLEC1B). Mice lacking fibroblastic reticular cell PDPN or platelet CLEC-2 exhibited significantly reduced levels of VE-cadherin (also known as CDH5), which is essential for overall vascular integrity, on HEVs. Infusion of wild-type platelets restored HEV integrity in Clec-2-deficient mice. Activation of CLEC-2 induced release of sphingosine-1-phosphate from platelets, which promoted expression of VE-cadherin on HEVs ex vivo. Furthermore, draining peripheral lymph nodes of immunized mice lacking sphingosine-1-phosphate had impaired HEV integrity similar to Pdpn- and Clec-2-deficient mice. These data demonstrate that local sphingosine-1-phosphate release after PDPN-CLEC-2-mediated platelet activation is critical for HEV integrity during immune responses.

Entry from the Lipid Bilayer: A Possible Pathway for Inhibition of a Peptide G Protein-Coupled Receptor by a Lipophilic Small Molecule.

The pathways that G protein-coupled receptor (GPCR) ligands follow as they bind to or dissociate from their receptors are largely unknown. Protease-activated receptor-1 (PAR1) is a GPCR activated by intramolecular binding of a tethered agonist peptide that is exposed by thrombin cleavage. By contrast, the PAR1 antagonist vorapaxar is a lipophilic drug that binds in a pocket almost entirely occluded from the extracellular solvent. The binding and dissociation pathway of vorapaxar is unknown. Starting with the crystal structure of vorapaxar bound to PAR1, we performed temperature-accelerated molecular dynamics simulations of ligand dissociation. In the majority of simulations, vorapaxar exited the receptor laterally into the lipid bilayer through openings in the transmembrane helix (TM) bundle. Prior to full dissociation, vorapaxar paused in metastable intermediates stabilized by interactions with the receptor and lipid headgroups. Derivatives of vorapaxar with alkyl chains predicted to extend between TM6 and TM7 into the lipid bilayer inhibited PAR1 with apparent on rates similar to that of the parent compound in cell signaling assays. These data are consistent with vorapaxar binding to PAR1 via a pathway that passes between TM6 and TM7 from the lipid bilayer, in agreement with the most consistent pathway observed by molecular dynamics. While there is some evidence of entry of the ligand into rhodopsin and lipid-activated GPCRs from the cell membrane, our study provides the first such evidence for a peptide-activated GPCR and suggests that metastable intermediates along drug binding and dissociation pathways can be stabilized by specific interactions between lipids and the ligand.

Imaging G protein-coupled receptors while quantifying their ligand-binding free-energy landscape.

Imaging native membrane receptors and testing how they interact with ligands is of fundamental interest in the life sciences but has proven remarkably difficult to accomplish. Here, we introduce an approach that uses force-distance curve-based atomic force microscopy to simultaneously image single native G protein-coupled receptors in membranes and quantify their dynamic binding strength to native and synthetic ligands. We measured kinetic and thermodynamic parameters for individual protease-activated receptor-1 (PAR1) molecules in the absence and presence of antagonists, and these measurements enabled us to describe PAR1's ligand-binding free-energy landscape with high accuracy. Our nanoscopic method opens an avenue to directly image and characterize ligand binding of native membrane receptors.

Platelet and Erythrocyte Sources of S1P Are Redundant for Vascular Development and Homeostasis, but Both Rendered Essential After Plasma S1P Depletion in Anaphylactic Shock.

RATIONALE: Sphingosine-1-phosphate (S1P) signaling is essential for vascular development and postnatal vascular homeostasis. The relative importance of S1P sources sustaining these processes remains unclear. OBJECTIVE: To address the level of redundancy in bioactive S1P provision to the developing and mature vasculature. METHODS AND RESULTS: S1P production was selectively impaired in mouse platelets, erythrocytes, endothelium, or smooth muscle cells by targeted deletion of genes encoding sphingosine kinases -1 and -2. S1P deficiency impaired aggregation and spreading of washed platelets and profoundly reduced their capacity to promote endothelial barrier function ex vivo. However, and in contrast to recent reports, neither platelets nor any other source of S1P was essential for vascular development, vascular integrity, or hemostasis/thrombosis. Yet rapid and profound depletion of plasma S1P during systemic anaphylaxis rendered both platelet- and erythrocyte-derived S1P essential for survival, with a contribution from blood endothelium observed only in the absence of circulating sources. Recovery was sensitive to aspirin in mice with but not without platelet S1P, suggesting that platelet activation and stimulus-response coupling is needed. S1P deficiency aggravated vasoplegia in this model, arguing a vital role for S1P in maintaining vascular resistance during recovery from circulatory shock. Accordingly, the S1P2 receptor mediated most of the survival benefit of S1P, whereas the endothelial S1P1 receptor was dispensable for survival despite its importance for maintaining vascular integrity. CONCLUSIONS: Although source redundancy normally secures essential S1P signaling in developing and mature blood vessels, profound depletion of plasma S1P renders both erythrocyte and platelet S1P pools necessary for recovery and high basal plasma S1P levels protective during anaphylactic shock.

High-resolution crystal structure of human protease-activated receptor 1.

Protease-activated receptor 1 (PAR1) is the prototypical member of a family of G-protein-coupled receptors that mediate cellular responses to thrombin and related proteases. Thrombin irreversibly activates PAR1 by cleaving the amino-terminal exodomain of the receptor, which exposes a tethered peptide ligand that binds the heptahelical bundle of the receptor to affect G-protein activation. Here we report the 2.2 Å resolution crystal structure of human PAR1 bound to vorapaxar, a PAR1 antagonist. The structure reveals an unusual mode of drug binding that explains how a small molecule binds virtually irreversibly to inhibit receptor activation by the tethered ligand of PAR1. In contrast to deep, solvent-exposed binding pockets observed in other peptide-activated G-protein-coupled receptors, the vorapaxar-binding pocket is superficial but has little surface exposed to the aqueous solvent. Protease-activated receptors are important targets for drug development. The structure reported here will aid the development of improved PAR1 antagonists and the discovery of antagonists to other members of this receptor family.

Gαi/o-coupled receptor signaling restricts pancreatic ß-cell expansion.

Gi-GPCRs, G protein-coupled receptors that signal via Gα proteins of the i/o class (Gαi/o), acutely regulate cellular behaviors widely in mammalian tissues, but their impact on the development and growth of these tissues is less clear. For example, Gi-GPCRs acutely regulate insulin release from pancreatic ß cells, and variants in genes encoding several Gi-GPCRs--including the α-2a adrenergic receptor, ADRA2A--increase the risk of type 2 diabetes mellitus. However, type 2 diabetes also is associated with reduced total ß-cell mass, and the role of Gi-GPCRs in establishing ß-cell mass is unknown. Therefore, we asked whether Gi-GPCR signaling regulates ß-cell mass. Here we show that Gi-GPCRs limit the proliferation of the insulin-producing pancreatic ß cells and especially their expansion during the critical perinatal period. Increased Gi-GPCR activity in perinatal ß cells decreased ß-cell proliferation, reduced adult ß-cell mass, and impaired glucose homeostasis. In contrast, Gi-GPCR inhibition enhanced perinatal ß-cell proliferation, increased adult ß-cell mass, and improved glucose homeostasis. Transcriptome analysis detected the expression of multiple Gi-GPCRs in developing and adult ß cells, and gene-deletion experiments identified ADRA2A as a key Gi-GPCR regulator of ß-cell replication. These studies link Gi-GPCR signaling to ß-cell mass and diabetes risk and identify it as a potential target for therapies to protect and increase ß-cell mass in patients with diabetes.

Sphingosine 1-phosphate receptor-1 in cardiomyocytes is required for normal cardiac development.

Sphingosine 1-phosphate (S1P) is a bioactive lipid that acts via G protein-coupled receptors. The S1P receptor S1P1, encoded by S1pr1, is expressed in developing heart but its roles there remain largely unexplored. Analysis of S1pr1 LacZ knockin embryos revealed ß-galactosidase staining in cardiomyocytes in the septum and in the trabecular layer of hearts collected at 12.5 days post coitus (dpc) and weak staining in the inner aspect of the compact layer at 15.5 dpc and later. Nkx2-5-Cre- and Mlc2a-Cre-mediated conditional knockout of S1pr1 led to ventricular noncompaction and ventricular septal defects at 18.5 dpc and to perinatal lethality in the majority of mutants. Further analysis of Mlc2a-Cre conditional mutants revealed no gross phenotype at 12.5 dpc but absence of the normal increase in the number of cardiomyocytes and the thickness of the compact layer at 13.5 dpc and after. Consistent with relative lack of a compact layer, in situ hybridization at 13.5 dpc revealed expression of trabecular markers extending almost to the epicardium in mutants. Mutant hearts also showed decreased myofibril organization in the compact but not trabecular myocardium at 12.5 dpc. These results suggest that S1P signaling via S1P1 in cardiomyocytes plays a previously unknown and necessary role in heart development in mice.

Mice expressing a mutant form of fibrinogen that cannot support fibrin formation exhibit compromised antimicrobial host defense.

Fibrin(ogen) is central to hemostasis and thrombosis and also contributes to multiple physiologic and pathologic processes beyond coagulation. However, the precise contribution of soluble fibrinogen vs insoluble fibrin matrices to vascular integrity, tissue repair, inflammation, and disease has been undefined and unapproachable. To establish the means to distinguish fibrinogen- and fibrin-dependent processes in vivo, Fib(AEK) mice were generated that carry normal levels of circulating fibrinogen but lack the capacity for fibrin polymer formation due to a germ-line mutation in the Aα chain thrombin cleavage site. Homozygous Fib(AEK) mice developed to term and exhibited postnatal survival superior to that of fibrinogen-deficient mice. Unlike fibrinogen-deficient mice, platelet-rich plasma from Fib(AEK) mice supported normal platelet aggregation in vitro, highlighting that fibrinogen(AEK) retains the functional capacity to support interactions with platelets. Thrombin failed to release fibrinopeptide-A from fibrinogen(AEK) and failed to induce polymer formation with Fib(AEK) plasma or purified fibrinogen(AEK) in 37°C mixtures regardless of incubation time. Fib(AEK) mice displayed both an absence of fibrin polymer formation following liver injury, as assessed by electron microscopy, and a failure to generate stable occlusive thrombi following FeCl3 injury of carotid arteries. Fib(AEK) mice exhibited a profound impediment in Staphylococcus aureus clearance following intraperitoneal infection similar to fibrinogen-deficient mice, yet Fib(AEK) mice displayed a significant infection dose-dependent survival advantage over fibrinogen-deficient mice following peritonitis challenge. Collectively, these findings establish for the first time that fibrin polymer is the molecular form critical for antimicrobial mechanisms while simultaneously highlighting biologically meaningful contributions and functions of the soluble molecule.

Systemic Metronidazole May Not Reduce Posthemorrhoidectomy Pain: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Hemorrhoidectomy is associated with significant postoperative pain. Oral metronidazole has been recommended as an adjunct to improve posthemorrhoidectomy analgesia. OBJECTIVE: This study aimed to evaluate the impact of oral metronidazole on patient-reported pain following hemorrhoidectomy. DATA SOURCES: We conducted a systematic search in the MEDLINE, EMBASE, ISI Web of Science, and Cochrane Central Register of Controlled Trials databases. STUDY SELECTION: Randomized controlled trials examining adults who underwent surgical hemorrhoidectomy were included. Participants in an active intervention group received oral metronidazole postoperatively, and those in a control group received placebo or usual care. Postoperative pain was assessed for at least 3 days postoperatively. INTERVENTION: A random-effects model was used. MAIN OUTCOMES MEASURES: The primary outcome was pain during the first 2 postoperative weeks, measured on a visual analogue scale. The secondary outcome was time to return to normal activities. RESULTS: Patients who received oral metronidazole had significantly lower reported pain scores on postoperative day 1 (standardized mean difference, -0.87 ± 0.44; 95% CI, -1.73 to -0.015; p = 0.046; n = 4) and day 4 (standardized mean difference, -1.43 ± 0.71; 95% CI, -2.83 to -0.037; p = 0.044; n = 3). Metronidazole use was associated with a significantly shorter time to return to normal activities (standardized mean difference, -0.76 ± 0.34; 95% CI, -1.43 to -0.088, p = 0.027). The improvements disappeared in a sensitivity analysis excluding the largest trial with a high risk of bias, and no significance was observed during the remaining postoperative days. LIMITATIONS: The meta-analysis was limited by lack of double blinding, absence of a placebo, and unclear or high risk of bias in a proportion of the included trials. CONCLUSIONS: Although a favorable adverse effect profile supports consideration of oral metronidazole to reduce posthemorrhoidectomy pain, pooled analysis reveals inconsistent results with no pain reduction on most postoperative days. The current recommendation for routine prescription of oral metronidazole should be reevaluated in the absence of additional well-designed trials.

Common variants in the human platelet PAR4 thrombin receptor alter platelet function and differ by race.

Human platelets express 2 thrombin receptors: protease-activated receptor (PAR)-1 and PAR4. Recently, we reported 3.7-fold increased PAR4-mediated aggregation kinetics in platelets from black subjects compared with white subjects. We now show that platelets from blacks (n = 70) express 14% more PAR4 protein than those from whites (n = 84), but this difference is not associated with platelet PAR4 function. Quantitative trait locus analysis identified 3 common single nucleotide polymorphisms in the PAR4 gene (F2RL3) associated with PAR4-induced platelet aggregation. Among these single nucleotide polymorphisms, rs773902 determines whether residue 120 in transmembrane domain 2 is an alanine (Ala) or threonine (Thr). Compared with the Ala120 variant, Thr120 was more common in black subjects than in white subjects (63% vs 19%), was associated with higher PAR4-induced human platelet aggregation and Ca2+ flux, and generated greater inositol 1,4,5-triphosphate in transfected cells. A second, less frequent F2RL3 variant, Phe296Val, was only observed in blacks and abolished the enhanced PAR4-induced platelet aggregation and 1,4,5-triphosphate generation associated with PAR4-Thr120. PAR4 genotype did not affect vorapaxar inhibition of platelet PAR1 function, but a strong pharmacogenetic effect was observed with the PAR4-specific antagonist YD-3 [1-benzyl-3(ethoxycarbonylphenyl)-indazole]. These findings may have an important pharmacogenetic effect on the development of new PAR antagonists.

Redundancy and interaction of thrombin- and collagen-mediated platelet activation in tail bleeding and carotid thrombosis in mice.

OBJECTIVE: Current antiplatelet strategies to prevent myocardial infarction and stroke are limited by bleeding risk. A better understanding of the roles of distinct platelet-activating pathways is needed. We determined whether platelet activation by 2 key primary activators, thrombin and collagen, plays distinct, redundant, or interacting roles in tail bleeding and carotid thrombosis in mice. APPROACH AND RESULTS: Platelets from mice deficient for the thrombin receptor protease-activated receptor-4 (Par4) and the collagen receptor glycoprotein VI protein (GPVI) lack responses to thrombin and collagen, respectively. We examined tail bleeding and FeCl3-induced carotid artery occlusion in mice lacking Par4, GPVI, or both. We also examined a series of Par mutants with increasing impairment of thrombin signaling in platelets. Ablation of thrombin signaling alone by Par4 deficiency increased blood loss in the tail bleeding assay and impaired occlusive thrombus formation in the carotid occlusion assay. GPVI deficiency alone had no effect. Superimposing GPVI deficiency on Par4 deficiency markedly increased effect size in both assays. In contrast to complete ablation of thrombin signaling, 9- and 19-fold increases in EC50 for thrombin-induced platelet activation had only modest effects. CONCLUSIONS: The observation that loss of Par4 uncovered large effects of GPVI deficiency implies that Par4 and GPVI made independent, partially redundant contributions to occlusive thrombus formation in the carotid and to hemostatic clot formation in the tail under the experimental conditions examined. At face value, these results suggest that thrombin- and collagen-induced platelet activation can play partially redundant roles, despite important differences in how these agonists are made available to platelets.

Preoperative chemotherapy for resectable thoracic esophageal cancer.

BACKGROUND: Surgery has been the treatment of choice for patients with localized esophageal cancer. Several studies have investigated whether preoperative chemotherapy followed by surgery leads to improvement in cure rates, but individual reports have provided conflicting results. An explicit systematic update of the role of preoperative chemotherapy in the treatment of patients with resectable thoracic esophageal cancer is, therefore, warranted. OBJECTIVES: The objective of this review is to determine the role of preoperative chemotherapy in the treatment of patients with resectable thoracic esophageal carcinoma. SEARCH METHODS: We identified trials by searching the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 to 2013), EMBASE (1988 to 2013), and CANCERLIT (1993 to 2013). We did not confine our search to English language publications. We updated searches in CENTRAL, MEDLINE, and EMBASE in October 2013. SELECTION CRITERIA: All trials of patients with potentially resectable carcinoma of the esophagus (of any histologic type) who were randomly assigned to chemotherapy or no chemotherapy before surgery. DATA COLLECTION AND ANALYSIS: The primary outcome was survival, which was assessed with the use of hazard ratios. This is an amendment to the original review, which used risk ratios to assess survival at yearly intervals. Hazard ratios (HRs) have now been introduced to summarize the complete survival experience in a single analysis. Risk ratios (RRs) were used to compare rates of resection, tumor recurrences, and treatment morbidity and mortality. MAIN RESULTS: We identified a total of 13 randomized trials involving 2362 participants. Ten trials (2122 participants) reported sufficient detail on survival to be included in a meta-analysis for the primary outcome. Preoperative chemotherapy improves overall survival (HR 0.88, 95% confidence interval (CI) 0.80 to 0.96) and is associated with a significantly higher rate of complete (R0) resection (RR 1.11, 95% CI 1.03 to 1.19).No evidence suggests that the overall rate of resection (RR 0.96, 95% CI 0.92 to 1.01), tumor recurrence (RR 0.81, 95% CI 0.54 to 1.22) or nonfatal complications (RR 0.90; 95% CI 0.76 to 1.06) was different for preoperative chemotherapy compared with surgery alone. Trials reported risks of toxicity with chemotherapy that ranged from 11% to 90%. AUTHORS' CONCLUSIONS: In summary, preoperative chemotherapy plus surgery offers a survival advantage compared with surgery alone for patients with resectable thoracic esophageal cancer, but the evidence is of moderate quality. Some evidence of toxicity and preoperative mortality have been associated with chemotherapy.

Is it safe to wait? The effect of surgical wait time on survival in patients with non-small cell lung cancer.

BACKGROUND: The effect of surgical wait times on survival in patients with non-small cell lung cancer (NSCLC) remains largely unknown. Our objective was to determine the effect of surgical wait time on survival and incidence of upstaging in patients with stage I and II NSCLC. METHODS: All patients with clinical stage I and II NSCLC who underwent surgical resection in a single centre between January 2010 and December 2011 were reviewed. Analysis was stratified based on preoperative clinical stage. We assessed the effect of wait time on survival using a Cox proportional hazard model with wait time in months as a categorical variable. Incidence of upstaging at least 1 stage was assessed using logistic regression. RESULTS: We identified 222 patients: 180 were stage I and 42 were stage II. For stage I, wait times up to 4 months had no significant effect on survival or incidence of upstaging. For stage II, patients waiting between 2 and 3 months had significantly decreased survival (hazard ratio 3.6, p = 0.036) and increased incidence of upstaging (odds ratio 2.0, p = 0.020) than those waiting 0 to 1 month. For those waiting between 1 and 2 months, there was no significant difference in survival or upstaging. CONCLUSION: We did not identify an effect of wait time up to 4 months on survival or upstaging for patients with stage I NSCLC. For patients with stage II disease, wait times greater than 2 months adversely affected survival and upstaging.

CONTEXTE: En chirurgie, l'effet des temps d'attente sur la survie des patients atteints d'un cancer du poumon non à petites cellules (CPNPC) demeure pour une bonne part inconnu. Notre objectif était de déterminer l'effet des temps d'attente sur la survie et sur l'incidence de la restadification à un niveau plus élevé chez les patients atteints d'un CPNPC de stade I et II. MÉTHODES: Tous les patients présentant un CPNPC clinique de stade I et II ayant subi une résection chirurgicale dans un seul centre entre janvier 2010 et décembre 2011 ont été passés en revue. L'analyse a été stratifiée selon le stade clinique préopératoire. Nous avons évalué l'effet des temps d'attente sur la survie à l'aide d'un modèle de risques proportionnels de Cox, les temps d'attente en mois ayant servi de variable catégorielle. L'incidence de la restadification à la hausse d'au moins un stade a été évaluée par régression logistique. RÉSULTATS: Nous avons recensé 222 patients : 180 de stade I et 42 de stade II. Pour le stade I, les temps d'attente allant jusqu'à 4 mois n'ont eu aucun effet significatif sur la survie ou sur l'incidence de la restadification. Pour les stades II, les patients ayant attendu de 2 à trois 3 mois ont présenté une réduction significative de la survie (risque relatif 3,6, p = 0,036) et une incidence accrue de restadification (rapport des cotes 2,0, p = 0,02) comparativement à ceux qui avaient attendu 1 mois et moins. Chez les patients ayant attendu 1 ou 2 mois, on n'a noté aucune différence significative sur la survie ou la restadification. CONCLUSION: Nous n'avons observé aucun effet d'une attente allant jusqu'à 4 mois sur la survie ou la restadification chez les patients atteints d'un CPNPC de stade I. Pour les patients atteints d'une maladie de stade II, les temps d'attente de plus de 2 mois ont eu un impact négatif sur la survie et la restadification.