Cell type-specific regulation of CFTR trafficking-on the verge of progress.

Trafficking of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein is a complex process that starts with its biosynthesis and folding in the endoplasmic reticulum. Exit from the endoplasmic reticulum (ER) is coupled with the acquisition of a compact structure that can be processed and traffic through the secretory pathway. Once reaching its final destination-the plasma membrane, CFTR stability is regulated through interaction with multiple protein partners that are involved in its post-translation modification, connecting the channel to several signaling pathways. The complexity of the process is further boosted when analyzed in the context of the airway epithelium. Recent advances have characterized in detail the different cell types that compose the surface epithelium and shifted the paradigm on which cells express CFTR and on their individual and combined contribution to the total expression (and function) of this chloride/bicarbonate channel. Here we review CFTR trafficking and its relationship with the knowledge on the different cell types of the airway epithelia. We explore the crosstalk between these two areas and discuss what is still to be clarified and how this can be used to develop more targeted therapies for CF.

Absence of EPAC1 Signaling to Stabilize CFTR in Intestinal Organoids.

The plasma membrane (PM) stability of the cystic fibrosis transmembrane conductance regulator (CFTR), the protein which when mutated causes Cystic Fibrosis (CF), relies on multiple interaction partners that connect CFTR to signaling pathways, including cAMP signaling. It was previously shown that activation of exchange protein directly activated by cAMP 1 (EPAC1) by cAMP promotes an increase in CFTR PM levels in airway epithelial cells. However, the relevance of this pathway in other tissues, particularly the intestinal tissue, remains uncharacterized. Here, we used Western blot and forskolin-induced swelling assay to demonstrate that the EPAC1 protein is not expressed in the intestinal organoid model, and consequently the EPAC1 stabilization pathway is not in place. On the other hand, using cell surface biotinylation, EPAC1-mediated stabilization of PM CFTR is observed in intestinal cell lines. These results indicate that the EPAC1 stabilization pathway also occurs in intestinal cells and is a potential target for the development of novel combinatorial therapies for treatment of CF.

A randomized clinical trial to evaluate the efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valve and atrial fibrillation or flutter: rationale and design of the RIVER trial

Background The efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valves and atrial fibrillation or flutter remain uncertain. Design RIVER was an academic-led, multicenter, open-label, randomized, non-inferiority trial with blinded outcome adjudication that enrolled 1005 patients from 49 sites in Brazil. Patients with a bioprosthetic mitral valve and atrial fibrillation or flutter were randomly assigned (1:1) to rivaroxaban 20 mg once daily (15 mg in those with creatinine clearance <50 mL/min) or dose-adjusted warfarin (target international normalized ratio 2.0-30.); the follow-up period was 12 months. The primary outcome was a composite of all-cause mortality, stroke, transient ischemic attack, major bleeding, valve thrombosis, systemic embolism, or hospitalization for heart failure. Secondary outcomes included individual components of the primary composite outcome, bleeding events, and venous thromboembolism. Summary RIVER represents the largest trial specifically designed to assess the efficacy and safety of a direct oral anticoagulant in patients with bioprosthetic mitral valves and atrial fibrillation or flutter. The results of this trial can inform clinical practice and international guidelines.

A randomized clinical trial to evaluate the efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valve and atrial fibrillation or flutter: Rationale and design of the RIVER trial.

The efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valves and atrial fibrillation or flutter remain uncertain. DESIGN: RIVER was an academic-led, multicenter, open-label, randomized, non-inferiority trial with blinded outcome adjudication that enrolled 1005 patients from 49 sites in Brazil. Patients with a bioprosthetic mitral valve and atrial fibrillation or flutter were randomly assigned (1:1) to rivaroxaban 20 mg once daily (15 mg in those with creatinine clearance <50 mL/min) or dose-adjusted warfarin (target international normalized ratio 2.0-30.); the follow-up period was 12 months. The primary outcome was a composite of all-cause mortality, stroke, transient ischemic attack, major bleeding, valve thrombosis, systemic embolism, or hospitalization for heart failure. Secondary outcomes included individual components of the primary composite outcome, bleeding events, and venous thromboembolism. SUMMARY: RIVER represents the largest trial specifically designed to assess the efficacy and safety of a direct oral anticoagulant in patients with bioprosthetic mitral valves and atrial fibrillation or flutter. The results of this trial can inform clinical practice and international guidelines.

Rivaroxaban in Patients with Atrial Fibrillation and a Bioprosthetic Mitral Valve.

BACKGROUND: The effects of rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve remain uncertain. METHODS: In this randomized trial, we compared rivaroxaban (20 mg once daily) with dose-adjusted warfarin (target international normalized ratio, 2.0 to 3.0) in patients with atrial fibrillation and a bioprosthetic mitral valve. The primary outcome was a composite of death, major cardiovascular events (stroke, transient ischemic attack, systemic embolism, valve thrombosis, or hospitalization for heart failure), or major bleeding at 12 months. RESULTS: A total of 1005 patients were enrolled at 49 sites in Brazil. A primary-outcome event occurred at a mean of 347.5 days in the rivaroxaban group and 340.1 days in the warfarin group (difference calculated as restricted mean survival time, 7.4 days; 95% confidence interval [CI], -1.4 to 16.3; P<0.001 for noninferiority). Death from cardiovascular causes or thromboembolic events occurred in 17 patients (3.4%) in the rivaroxaban group and in 26 (5.1%) in the warfarin group (hazard ratio, 0.65; 95% CI, 0.35 to 1.20). The incidence of stroke was 0.6% in the rivaroxaban group and 2.4% in the warfarin group (hazard ratio, 0.25; 95% CI, 0.07 to 0.88). Major bleeding occurred in 7 patients (1.4%) in the rivaroxaban group and in 13 (2.6%) in the warfarin group (hazard ratio, 0.54; 95% CI, 0.21 to 1.35). The frequency of other serious adverse events was similar in the two groups. CONCLUSIONS: In patients with atrial fibrillation and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin with respect to the mean time until the primary outcome of death, major cardiovascular events, or major bleeding at 12 months. (Funded by PROADI-SUS and Bayer; RIVER ClinicalTrials.gov number, NCT02303795.).

Rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve

BACKGROUND The effects of rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve remain uncertain. METHODS In this randomized trial, we compared rivaroxaban (20 mg once daily) with dose adjusted warfarin (target international normalized ratio, 2.0 to 3.0) in patients with atrial fibrillation and a bioprosthetic mitral valve. The primary outcome was a composite of death, major cardiovascular events (stroke, transient ischemic attack, systemic embolism, valve thrombosis, or hospitalization for heart failure), or major bleeding at 12 months. RESULTS A total of 1005 patients were enrolled at 49 sites in Brazil. A primary-outcome event occurred at a mean of 347.5 days in the rivaroxaban group and 340.1 days in the warfarin group (difference calculated as restricted mean survival time, 7.4 days; 95% confidence interval [CI], −1.4 to 16.3; P<0.001 for noninferiority). Death from cardiovascular causes or thromboembolic events occurred in 17 patients (3.4%) in the rivaroxaban group and in 26 (5.1%) in the warfarin group (hazard ratio, 0.65; 95% CI, 0.35 to 1.20). The incidence of stroke was 0.6% in the rivaroxaban group and 2.4% in the warfarin group (hazard ratio, 0.25; 95% CI, 0.07 to 0.88). Major bleeding occurred in 7 patients (1.4%) in the rivaroxaban group and in 13 (2.6%) in the warfarin group (hazard ratio, 0.54; 95% CI, 0.21 to 1.35). The frequency of other serious adverse events was similar in the two groups. CONCLUSIONS In patients with atrial fibrillation and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin with respect to the mean time until the primary outcome of death, major cardiovascular events, or major bleeding at 12 months.

Cytoskeleton regulators CAPZA2 and INF2 associate with CFTR to control its plasma membrane levels under EPAC1 activation.

Cystic Fibrosis (CF), the most common lethal autosomic recessive disorder among Caucasians, is caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) protein, a cAMP-regulated chloride channel expressed at the apical surface of epithelial cells. Cyclic AMP regulates both CFTR channel gating through a protein kinase A (PKA)-dependent process and plasma membane (PM) stability through activation of the exchange protein directly activated by cAMP1 (EPAC1). This cAMP effector, when activated promotes the NHERF1:CFTR interaction leading to an increase in CFTR at the PM by decreasing its endocytosis. Here, we used protein interaction profiling and bioinformatic analysis to identify proteins that interact with CFTR under EPAC1 activation as possible regulators of this CFTR PM anchoring. We identified an enrichment in cytoskeleton related proteins among which we characterized CAPZA2 and INF2 as regulators of CFTR trafficking to the PM. We found that CAPZA2 promotes wt-CFTR trafficking under EPAC1 activation at the PM whereas reduction of INF2 levels leads to a similar trafficking promotion effect. These results suggest that CAPZA2 is a positive regulator and INF2 a negative one for the increase of CFTR at the PM after an increase of cAMP and concomitant EPAC1 activation. Identifying the specific interactions involving CFTR and elicited by EPAC1 activation provides novel insights into late CFTR trafficking, insertion and/or stabilization at the PM and highlighs new potential therapeutic targets to tackle CF disease.

5-Nitroimidazole-derived Schiff bases and their copper(II) complexes exhibit potent antimicrobial activity against pathogenic anaerobic bacteria.

In the present work a family of novel secnidazole-derived Schiff base compounds and their copper(II) complexes were synthesized. The antimicrobial activities of the compounds were evaluated against clinically important anaerobic bacterial strains. The compounds exhibited in vitro antibacterial activity against Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides vulgatus, Bacteroides ovatus, Parabacteroides distasonis and Fusubacterium nucleatum pathogenic anaerobic bacteria. Upon coordination to copper(II) the antibacterial activity significantly increased in several cases. Some derivatives were even more active than the antimicrobial drugs secnidazole and metronidazole. Therefore, the compounds under study are suitable for in vivo evaluation and the microorganisms should be classified as susceptible to them. Electrochemical studies on the reduction of the nitro group revealed that the compounds show comparable reduction potentials, which are in the same range of the bio-reducible drugs secnidazole and benznidazole. The nitro group reduction potential is more favorable for the copper(II) complexes than for the starting ligands. Hence, the antimicrobial activities of the compounds under study might in part be related to intracellular bio-reduction activation. Considering the increasing resistance rates of anaerobic bacteria against a wide range of antimicrobial drugs, the present work constitutes an important contribution to the development of new antibacterial drug candidates.

An adapted double threshold protocol for spastic muscles.

The onset of muscle contraction has been an important element in the understanding of human motor control system as well as in the development of medical devices. This task is problematic in the study of spasticity using surface Electromyography (sEMG). In fact, spasticity is characterized by involuntary muscle contractions that can be seen as both, a non-stationary background if they are weak or a severe non-stationary EMG signal if they are strong. In other hand, these sEMG signals present a very low signal to noise ratio, beyond the added noise that contaminates this signal. The double threshold protocol presumes non-stationary muscle activation under a stationary environment which does not accommodate non-stationary background conditions. Apart from that the Shewhart protocol which makes part of the Double Threshold Protocol (DTP) presumes an initial segment containing only noise which can't be guaranteed under spastic conditions. These are the main causes of failures of state of the art approaches when applied to sEMG spastic muscles. This paper proposes dealing with these constraints by adapting the first threshold to the noise conditions via Signal to Noise Ratio (SNR) estimation, which depends on the severity of the disease. The main idea is tuning the first threshold to low SNR conditions since it is where the DTP most degrades. This tuning is done in sEMG artificially contaminated at different SNRs where the multiple of standard deviation is heuristically determined based on experimentation. Noise is estimated in low energy segments instead of in an initial segment that can be contaminated by involuntary muscle contractions. The proposed algorithm was tested in sEMG signals from the Biceps Braquialis of 13 healthy individuals and in 9315 signals recorded in 23 subjects with spasticity. Improvements of more than 23% were obtained when compared with the classical DTP in moderate to severe spasticity.

Impact of metabolic syndrome on the outcome of patients with stable coronary artery disease: 2-year follow-up of the MASS II study.

OBJECTIVE: We characterized the impact of the metabolic syndrome (MetS) and its components on cardiovascular adverse events in patients with symptomatic chronic multivessel coronary artery disease, which have been followed prospectively for 2 years. METHODS: Patients enrolled in the MASS II study were evaluated for each component of the MetS, as well as the full syndrome. RESULTS: The criteria for MetS were fulfilled in 52% of patients. The presence of MetS (P<0.05), glucose intolerance (P=0.007), and diabetes (P=0.04) was associated with an increased mortality in our studied population. Moreover, despite a clear tendency for each of its components to increase the mortality risk, only the presence of the MetS significantly increased the risk of mortality among nondiabetic study participants in a multivariate model (P=0.03, relative risk 3.5, 95% confidence interval 1.1-6). Finally, MetS was still associated with increased mortality even after adjustment for diabetes status. These results indicate a strong and consistent relationship of the MetS with mortality in patients with stable coronary artery disease. CONCLUSION: Although glucose homeostasis seems to be the major force driving the increased risk of MetS, the operational diagnosis of MetS still has information for stratifying patients when diabetes information is taken into account.

Monophasic versus biphasic waveform shocks for atrial fibrillation cardioversion in patients with concomitant amiodarone therapy.

AIMS: With transthoracic cardioversion of atrial fibrillation (AF), biphasic are more effective than monophasic waveforms. We sought to determine the ideal energy levels for biphasic waveforms. Methods We compared biphasic truncated exponential waveforms with monophasic damped sine waveform defibrillators, in a prospective, single-centre, randomized (1:1 ratio) study. The study included 154 patients receiving concomitant amiodarone; 77 received serial biphasic (50, 100, 150, up to 175 J) and 77 monophasic shocks (100, 200, 300, up to 360 J), as necessary. Results First-shock efficacy was similar in the two groups (57 vs. 55%, P = 0.871, respectively), as were serial-shocks (90 vs. 92%, P = 0.780). Both groups received equal numbers of shocks (1.8 +/- 1.1 vs. 1.7 +/- 1.0, P = 0.921). In both groups, serum creatine kinase levels showed a small but significant increase. The increase was, however, higher in the monophasic group. CONCLUSION: In patients with concomitant amiodarone therapy, biphasic truncated exponential shocks, using half the energy, were as effective as monophasic damped sine shocks. The biphasic scheme was not more efficacious for cardioverting AF. In our population, a first shock of at least 100 J seemed advisable with either waveform. If necessary, escalating shocks must be performed, but ideal levels of increase per shock are still uncertain for biphasic waveforms.

Fibrilação atrial aguda na unidade de emergência: qual a droga ideal para rápida reversäo ao ritmo sinusal? / Acute Atrial Fibrillation. Which is the Best Drug for Sinus Rhythm Conversion in the Emergency Room ?

Objetivo - Comparar o tempo e o índice de sucesso para reversäo da fibrilaçäo atrial (FA) aguda, com o uso de amiodarona, procainamida ou quinidina. Métodos - Aleatoriamente, 60 pacientes com FA aguda foram divididos em três grupos, recebendo o grupo quinidina (GQ), constituído de 21 pacientes, digital EV + quinidina até 600mg VO; o grupo procainamida (GP) com 23 pacientes, digital EV + 10mg/kg de procainamida EV e o grupo amiodarona (GA), com 16 pacientes 5mg/kg de amiodarona EV. O período de observaçäo foi de no máximo 4h, através de Holter. Na análise estatíca foi utilizado o teste de x2 com o método de Kruskall-Wallis, considerando-se significativo p<0,05. Resultados - Os três grupos foram similares quanto a idade, sexo e tempo de instalaçäo da FA. A reversäo ocorreu em 71,4 por cento dos casos no GQ, em 47,8 por cento no GP e em 50 por cento no GA, (p>0,05). O tempo para reversäo em minutos foi de 112 + ou - 43 no G!, de 44,1 + ou - 28 no GP, de 20 + ou - 13 no GA, sendo menor e estatisticamente significante no GP e, principalmente, no GA (p= 0,001) em relaçäo ao GQ. Os efeitos colaterais foram mais freqüentes no GP, embora sem significância estatística. Conclusäo - A amiodarona, especialmente na ausência de cardiopatia de base, é uma boa opçäo para maior rapidez na reversäo da FA, enquanto a quinidina propicia maior taxa de reversäo, com menos efeitos colaterais