Non-coding regulatory sRNAs from bacteria of the Burkholderia cepacia complex.

Small non-coding RNAs (sRNAs) are key regulators of post-transcriptional gene expression in bacteria. Hundreds of sRNAs have been found using in silico genome analysis and experimentally based approaches in bacteria of the Burkholderia cepacia complex (Bcc). However, and despite the hundreds of sRNAs identified so far, the number of functionally characterized sRNAs from these bacteria remains very limited. In this mini-review, we describe the general characteristics of sRNAs and the main mechanisms involved in their action as regulators of post-transcriptional gene expression, as well as the work done so far in the identification and characterization of sRNAs from Bcc. The number of functionally characterized sRNAs from Bcc is expected to increase and to add new knowledge on the biology of these bacteria, leading to novel therapeutic approaches to tackle the infections caused by these opportunistic pathogens, particularly severe among cystic fibrosis patients. KEY POINTS: •Hundreds of sRNAs have been identified in Burkholderia cepacia complex bacteria (Bcc). •A few sRNAs have been functionally characterized in Bcc. •Functionally characterized Bcc sRNAs play major roles in metabolism, biofilm formation, and virulence.

Advances in Human Pathogen Control-A 21st Century Challenge.

The emergence of new pathogens, coupled with the reemergence of old pathogens and the steep worldwide increase in multiple resistances to available antimicrobials, poses major challenges to human health at the global scale [...].

Identification of Burkholderia cenocepacia non-coding RNAs expressed during Caenorhabditis elegans infection.

Small non-coding RNAs (sRNAs) are key regulators of post-transcriptional gene expression in bacteria. Despite the identification of hundreds of bacterial sRNAs, their roles on bacterial physiology and virulence remain largely unknown, as is the case of bacteria of the Burkholderia cepacia complex (Bcc). Bcc is a group of opportunistic pathogens with relatively large genomes that can cause lethal lung infections amongst cystic fibrosis (CF) patients. To characterise sRNAs expressed by Bcc bacteria when infecting a host, the nematode Caenorhabditis elegans was used as an infection model by the epidemic CF strain B. cenocepacia J2315. A total of 108 new and 31 previously described sRNAs with a predicted Rho independent terminator were identified, most of them located on chromosome 1. RIT11b, a sRNA downregulated under C. elegans infection conditions, was shown to directly affect B. cenocepacia virulence, biofilm formation, and swimming motility. RIT11b overexpression reduced the expression of the direct targets dusA and pyrC, involved in biofilm formation, epithelial cell adherence, and chronic infections in other organisms. The in vitro direct interaction of RIT11b with the dusA and pyrC messengers was demonstrated by electrophoretic mobility shift assays. To the best of our knowledge this is the first report on the functional characterization of a sRNA directly involved in B. cenocepacia virulence. KEY POINTS: • 139 sRNAs expressed by B. cenocepacia during C. elegans infection were identified • The sRNA RIT11b affects B. cenocepacia virulence, biofilm formation, and motility • RIT11b directly binds to and regulates dusA and pyrC mRNAs.

Tuning the Biological Activity of Camphorimine Complexes through Metal Selection.

The cytotoxic activity of four sets of camphorimine complexes based on the Cu(I), Cu(II), Ag(I), and Au(I) metal sites were assessed against the cisplatin-sensitive A2780 and OVCAR3 ovarian cancer cells. The results showed that the gold complexes were ca. one order of magnitude more active than the silver complexes, which in turn were ca. one order of magnitude more active than the copper complexes. An important finding was that the cytotoxic activity of the Ag(I) and Au(I) camphorimine complexes was higher than that of cisplatin. Another relevant aspect was that the camphorimine complexes did not interact significantly with DNA, in contrast with cisplatin. The cytotoxic activity of the camphorimine complexes displayed a direct relationship with the cellular uptake by OVCAR3 cells, as ascertained by PIXE (particle-induced X-ray emission). The levels of ROS (reactive oxygen species) formation exhibited an inverse relationship with the reduction potentials for the complexes with the same metal, as assessed by cyclic voltammetry. In order to gain insight into the toxicity of the complexes, their cytotoxicity toward nontumoral cells (HDF and V79 fibroblasts) was evaluated. The in vivo cytotoxicity of complex 5 using the nematode Caenorhabditis elegans was also assessed. The silver camphorimine complexes displayed the highest selectivity coefficients (activity vs. toxicity).

A Polyclonal Antibody Raised against the Burkholderia cenocepacia OmpA-like Protein BCAL2645 Impairs the Bacterium Adhesion and Invasion of Human Epithelial Cells In Vitro.

Respiratory infections by bacteria of the Burkholderia cepacia complex (Bcc) remain a life threat to cystic fibrosis (CF) patients, due to the faster lung function decline and the absence of effective eradication strategies. Immunotherapies are regarded as an attractive alternative to control and reduce the damages caused by these infections. In this work, we report the cloning and functional characterization of the OmpA-like BCAL2645 protein, previously identified and found to be immunoreactive against sera from CF patients with a record of Bcc infections. The BCAL2645 protein is shown to play a role in biofilm formation, adherence to mucins and invasion of human lung epithelial cells. The expression of the BCAL2645 protein was found to be increased in culture medium, mimicking the lungs of CF patients and microaerophilic conditions characteristic of the CF lung. Moreover, a polyclonal antibody raised against BCAL2645 was found to inhibit, by about 75 and 85%, the ability of B. cenocepacia K56-2 to bind and invade in vitro CFBE41o- human bronchial epithelial cells. These results highlight the potential of anti-BCAL2645 antibodies for the development of passive immunization therapies to protect CF patients against Bcc infections.

Bacterial Nosocomial Infections: Multidrug Resistance as a Trigger for the Development of Novel Antimicrobials.

Nosocomial bacterial infections are associated with high morbidity and mortality, posing a huge burden to healthcare systems worldwide. The ongoing COVID-19 pandemic, with the raised hospitalization of patients and the increased use of antimicrobial agents, boosted the emergence of difficult-to-treat multidrug-resistant (MDR) bacteria in hospital settings. Therefore, current available antibiotic treatments often have limited or no efficacy against nosocomial bacterial infections, and novel therapeutic approaches need to be considered. In this review, we analyze current antibacterial alternatives under investigation, focusing on metal-based complexes, antimicrobial peptides, and antisense antimicrobial therapeutics. The association of new compounds with older, commercially available antibiotics and the repurposing of existing drugs are also revised in this work.

Extracellular RNAs in Bacterial Infections: From Emerging Key Players on Host-Pathogen Interactions to Exploitable Biomarkers and Therapeutic Targets.

Non-coding RNAs (ncRNAs) are key regulators of post-transcriptional gene expression in prokaryotic and eukaryotic organisms. These molecules can interact with mRNAs or proteins, affecting a variety of cellular functions. Emerging evidence shows that intra/inter-species and trans-kingdom regulation can also be achieved with exogenous RNAs, which are exported to the extracellular medium, mainly through vesicles. In bacteria, membrane vesicles (MVs) seem to be the more common way of extracellular communication. In several bacterial pathogens, MVs have been described as a delivery system of ncRNAs that upon entry into the host cell, regulate their immune response. The aim of the present work is to review this recently described mode of host-pathogen communication and to foster further research on this topic envisaging their exploitation in the design of novel therapeutic and diagnostic strategies to fight bacterial infections.

Melhora no Consumo Máximo de Oxigênio e na Ventilação após Tratamento com Sacubitril-Valsartana / Maximal Oxygen Uptake and Ventilation Improvement Following Sacubitril-Valsartan Therapy

Resumo Fundamento O tratamento com sacubitril-valsartana teve seu benefício prognóstico confirmado no ensaio PARADIGM-HF. No entanto, dados sobre alterações no teste de esforço cardiopulmonar (TECP) com o uso de sacubitril-valsartana são escassos. Objetivo O objetivo deste estudo foi comparar os parâmetros do TECP antes e depois do tratamento com sacubitril-valsartana. Métodos Avaliação prospectiva de pacientes com insuficiência cardíaca (IC) crônica e fração de ejeção do ventrículo esquerdo ≤40%, mesmo sob terapia padrão otimizada, que iniciaram tratamento com sacubitril-valsartana, sem expectativa de tratamentos adicionais para a IC. Os dados do TECP foram coletados na semana anterior e 6 meses depois do tratamento com sacubitril-valsartana. Diferenças estatísticas com valor p <0,05 foram consideradas significativas. Resultados De 42 pacientes, 35 (83,3%) completaram o seguimento de 6 meses, uma vez que 2 (4,8%) morreram e 5 (11,9%) interromperam o tratamento devido a eventos adversos. A média de idade foi de 58,6±11,1 anos. A classe NYHA (classificação da New York Heart Association) melhorou em 26 (74,3%) pacientes. O consumo máximo de oxigênio (VO2max) (14,4 vs. 18,3 ml/kg/min, p<0,001), a inclinação VE/VCO2 (36,7 vs. 31,1, p<0,001) e a duração do exercício (487,8 vs. 640,3 s, p<0,001) também melhoraram com o uso de sacubitril-valsartana. O benefício foi mantido mesmo com a dose de 24/26 mg (13,5 vs. 19,2 ml/kg/min, p=0,018) de sacubitril-valsartana, desde que esta tenha sido a maior dose tolerada. Conclusões O tratamento com sacubitril-valsartana está associado a uma melhora acentuada do VO2max, da inclinação VE/VCO2 e da duração do exercício no TECP. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Abstract Background Sacubitril/valsartan had its prognosis benefit confirmed in the PARADIGM-HF trial. However, data on cardiopulmonary exercise testing (CPET) changes with sacubitril-valsartan therapy are scarce. Objective This study aimed to compare CPET parameters before and after sacubitril-valsartan therapy. Methods Prospective evaluation of chronic heart failure (HF) patients with left ventricular ejection fraction ≤40% despite optimized standard of care therapy, who started sacubitril-valsartan therapy, expecting no additional HF treatment. CPET data were gathered in the week before and 6 months after sacubitril-valsartan therapy. Statistical differences with a p-value <0.05 were considered significant. Results Out of 42 patients, 35 (83.3%) completed the 6-month follow-up, since 2 (4.8%) patients died and 5 (11.9%) discontinued treatment for adverse events. Mean age was 58.6±11.1 years. New York Heart Association class improved in 26 (74.3%) patients. Maximal oxygen uptake (VO2max) (14.4 vs. 18.3 ml/kg/min, p<0.001), VE/VCO2slope (36.7 vs. 31.1, p<0.001), and exercise duration (487.8 vs. 640.3 sec, p<0.001) also improved with sacubitril-valsartan. Benefit was maintained even with the 24/26 mg dose (13.5 vs. 19.2 ml/kg/min, p=0.018) of sacubitril-valsartan, as long as this was the highest tolerated dose. Conclusions Sacubitril-valsartan therapy is associated with marked CPET improvement in VO2max, VE/VCO2slope, and exercise duration. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Maximal Oxygen Uptake and Ventilation Improvement Following Sacubitril-Valsartan Therapy. / Melhora no Consumo Máximo de Oxigênio e na Ventilação após Tratamento com Sacubitril-Valsartana.

BACKGROUND: Sacubitril/valsartan had its prognosis benefit confirmed in the PARADIGM-HF trial. However, data on cardiopulmonary exercise testing (CPET) changes with sacubitril-valsartan therapy are scarce. OBJECTIVE: This study aimed to compare CPET parameters before and after sacubitril-valsartan therapy. METHODS: Prospective evaluation of chronic heart failure (HF) patients with left ventricular ejection fraction ≤40% despite optimized standard of care therapy, who started sacubitril-valsartan therapy, expecting no additional HF treatment. CPET data were gathered in the week before and 6 months after sacubitril-valsartan therapy. Statistical differences with a p-value <0.05 were considered significant. RESULTS: Out of 42 patients, 35 (83.3%) completed the 6-month follow-up, since 2 (4.8%) patients died and 5 (11.9%) discontinued treatment for adverse events. Mean age was 58.6±11.1 years. New York Heart Association class improved in 26 (74.3%) patients. Maximal oxygen uptake (VO2max) (14.4 vs. 18.3 ml/kg/min, p<0.001), VE/VCO2slope (36.7 vs. 31.1, p<0.001), and exercise duration (487.8 vs. 640.3 sec, p<0.001) also improved with sacubitril-valsartan. Benefit was maintained even with the 24/26 mg dose (13.5 vs. 19.2 ml/kg/min, p=0.018) of sacubitril-valsartan, as long as this was the highest tolerated dose. CONCLUSIONS: Sacubitril-valsartan therapy is associated with marked CPET improvement in VO2max, VE/VCO2slope, and exercise duration. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).

FUNDAMENTO: O tratamento com sacubitril-valsartana teve seu benefício prognóstico confirmado no ensaio PARADIGM-HF. No entanto, dados sobre alterações no teste de esforço cardiopulmonar (TECP) com o uso de sacubitril-valsartana são escassos. OBJETIVO: O objetivo deste estudo foi comparar os parâmetros do TECP antes e depois do tratamento com sacubitril-valsartana. MÉTODOS: Avaliação prospectiva de pacientes com insuficiência cardíaca (IC) crônica e fração de ejeção do ventrículo esquerdo ≤40%, mesmo sob terapia padrão otimizada, que iniciaram tratamento com sacubitril-valsartana, sem expectativa de tratamentos adicionais para a IC. Os dados do TECP foram coletados na semana anterior e 6 meses depois do tratamento com sacubitril-valsartana. Diferenças estatísticas com valor p <0,05 foram consideradas significativas. RESULTADOS: De 42 pacientes, 35 (83,3%) completaram o seguimento de 6 meses, uma vez que 2 (4,8%) morreram e 5 (11,9%) interromperam o tratamento devido a eventos adversos. A média de idade foi de 58,6±11,1 anos. A classe NYHA (classificação da New York Heart Association) melhorou em 26 (74,3%) pacientes. O consumo máximo de oxigênio (VO2max) (14,4 vs. 18,3 ml/kg/min, p<0,001), a inclinação VE/VCO2 (36,7 vs. 31,1, p<0,001) e a duração do exercício (487,8 vs. 640,3 s, p<0,001) também melhoraram com o uso de sacubitril-valsartana. O benefício foi mantido mesmo com a dose de 24/26 mg (13,5 vs. 19,2 ml/kg/min, p=0,018) de sacubitril-valsartana, desde que esta tenha sido a maior dose tolerada. CONCLUSÕES: O tratamento com sacubitril-valsartana está associado a uma melhora acentuada do VO2max, da inclinação VE/VCO2 e da duração do exercício no TECP. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).

Impact of Cardiorespiratory Fitness on the Obesity Paradox in Heart Failure with Reduced Ejection Fraction. / O Impacto da Aptidão Cardiorrespiratória no Paradoxo da Obesidade em Insuficiência Cardíaca com Fração de Ejeção Reduzida.

BACKGROUND: Higher body mass index (BMI) has been associated with improved outcomes in heart failure with reduced ejection fraction. This finding has led to the concept of the obesity paradox. OBJECTIVE: To investigate the impact of exercise tolerance and cardiorespiratory capacity on the obesity paradox. METHODS: Outpatients with symptomatic heart failure and left ventricular ejection fraction (LVEF) ≤ 40%, followed up in our center, prospectively underwent baseline comprehensive evaluation including clinical, laboratorial, electrocardiographic, echocardiographic, and cardiopulmonary exercise testing parameters. The study population was divided according to BMI (< 25, 25 - 29.9, and ≥ 30 kg/m2). All patients were followed for 60 months. The combined endpoint was defined as cardiac death, urgent heart transplantation, or need for mechanical circulatory support. P value < 0.05 was considered significant. RESULTS: In the 282 enrolled patients (75% male, 54 ± 12 years, BMI 27 ± 4 kg/m2, LVEF 27% ± 7%), the composite endpoint occurred in 24.4% during follow-up. Patients with higher BMI were older, and they had higher LVEF and serum sodium levels, as well as lower ventilatory efficiency (VE/VCO2) slope. VE/VCO2 and peak oxygen consumption (pVO2) were strong predictors of prognosis (p < 0.001). In univariable Cox regression analysis, higher BMI was associated with better outcomes (HR 0.940, CI 0.886 - 0.998, p 0.042). However, after adjusting for either VE/VCO2 slope or pVO2, the protective role of BMI disappeared. Survival benefit of BMI was not evident when patients were grouped according to cardiorespiratory fitness class (VE/VCO2, cut-off value 35, and pVO2, cut-off value 14 mL/kg/min). CONCLUSION: These results suggest that cardiorespiratory fitness outweighs the relationship between BMI and survival in patients with heart failure.

FUNDAMENTO: Índice de massa corporal (IMC) elevado tem sido associado a desfechos melhores em pacientes com insuficiência cardíaca com fração de ejeção reduzida. Este achado tem levado ao conceito do paradoxo da obesidade. OBJETIVO: Investigar o impacto de tolerância ao exercício e capacidade cardiorrespiratória no paradoxo da obesidade. MÉTODO: Pacientes ambulatoriais com insuficiência cardíaca sintomática e fração de ejeção ventricular esquerda (FEVE) ≤ 40%, acompanhados no nosso centro, foram prospectivamente submetidos à avaliação abrangente de linha de base incluindo parâmetros clínicos, laboratoriais, eletrocardiográficos, ecocardiográficos e de exercício cardiopulmonar. A população do estudo foi dividida de acordo com o IMC (< 25, 25 ­ 29,9 e ≥ 30 kg/m2). Todos os pacientes foram acompanhados durante 60 meses. O desfecho composto foi definido como morte cardíaca, transplante cardíaco urgente ou necessidade de suporte circulatório mecânico. Valores de p < 0,05 foram considerados significativos. RESULTADOS: Dos 282 pacientes incluídos (75% masculino, 54 ± 12 anos, IMC 27 ± 4 kg/m2, FEVE 27% ± 7%), o desfecho composto ocorreu em 24,4% durante o acompanhamento. Os pacientes com IMC elevado eram mais velhos e apresentavam FEVE e níveis séricos de sódio mais elevados, bem como menor inclinação de eficiência ventilatória (VE/VCO2). VE/VCO2 e consumo de oxigênio de pico (VO2p) eram fortes preditores prognósticos (p < 0,001). Na análise univariada de regressão de Cox, o IMC elevado foi associado a desfechos melhores (razão de risco 0,940, intervalo de confiança 0,886 ­ 0,998, p 0,042). Porém, após ajustar para ou inclinação VE/VCO2 ou VO2p, o papel protetor do IMC sumiu. O benefício de sobrevida do IMC não foi evidente quando os pacientes foram agrupados de acordo com a classe de aptidão cardiorrespiratória (VE/VCO2, valor de corte de 35, e VO2p, valor de corte de 14 mL/kg/min). CONCLUSÃO: Estes resultados sugerem que a aptidão cardiorrespiratória supera a relação entre o IMC e a sobrevida em pacientes com insuficiência cardíaca.

O Impacto da Aptidão Cardiorrespiratória no Paradoxo da Obesidade em Insuficiência Cardíaca com Fração de Ejeção Reduzida / Impact of Cardiorespiratory Fitness on the Obesity Paradox in Heart Failure with Reduced Ejection Fraction

Resumo Fundamento: Índice de massa corporal (IMC) elevado tem sido associado a desfechos melhores em pacientes com insuficiência cardíaca com fração de ejeção reduzida. Este achado tem levado ao conceito do paradoxo da obesidade. Objetivo: Investigar o impacto de tolerância ao exercício e capacidade cardiorrespiratória no paradoxo da obesidade. Método: Pacientes ambulatoriais com insuficiência cardíaca sintomática e fração de ejeção ventricular esquerda (FEVE) ≤ 40%, acompanhados no nosso centro, foram prospectivamente submetidos à avaliação abrangente de linha de base incluindo parâmetros clínicos, laboratoriais, eletrocardiográficos, ecocardiográficos e de exercício cardiopulmonar. A população do estudo foi dividida de acordo com o IMC (< 25, 25 - 29,9 e ≥ 30 kg/m2). Todos os pacientes foram acompanhados durante 60 meses. O desfecho composto foi definido como morte cardíaca, transplante cardíaco urgente ou necessidade de suporte circulatório mecânico. Valores de p < 0,05 foram considerados significativos. Resultados: Dos 282 pacientes incluídos (75% masculino, 54 ± 12 anos, IMC 27 ± 4 kg/m2, FEVE 27% ± 7%), o desfecho composto ocorreu em 24,4% durante o acompanhamento. Os pacientes com IMC elevado eram mais velhos e apresentavam FEVE e níveis séricos de sódio mais elevados, bem como menor inclinação de eficiência ventilatória (VE/VCO2). VE/VCO2 e consumo de oxigênio de pico (VO2p) eram fortes preditores prognósticos (p < 0,001). Na análise univariada de regressão de Cox, o IMC elevado foi associado a desfechos melhores (razão de risco 0,940, intervalo de confiança 0,886 - 0,998, p 0,042). Porém, após ajustar para ou inclinação VE/VCO2 ou VO2p, o papel protetor do IMC sumiu. O benefício de sobrevida do IMC não foi evidente quando os pacientes foram agrupados de acordo com a classe de aptidão cardiorrespiratória (VE/VCO2, valor de corte de 35, e VO2p, valor de corte de 14 mL/kg/min). Conclusão: Estes resultados sugerem que a aptidão cardiorrespiratória supera a relação entre o IMC e a sobrevida em pacientes com insuficiência cardíaca.

Abstract Background: Higher body mass index (BMI) has been associated with improved outcomes in heart failure with reduced ejection fraction. This finding has led to the concept of the obesity paradox. Objective: To investigate the impact of exercise tolerance and cardiorespiratory capacity on the obesity paradox. Methods: Outpatients with symptomatic heart failure and left ventricular ejection fraction (LVEF) ≤ 40%, followed up in our center, prospectively underwent baseline comprehensive evaluation including clinical, laboratorial, electrocardiographic, echocardiographic, and cardiopulmonary exercise testing parameters. The study population was divided according to BMI (< 25, 25 - 29.9, and ≥ 30 kg/m2). All patients were followed for 60 months. The combined endpoint was defined as cardiac death, urgent heart transplantation, or need for mechanical circulatory support. P value < 0.05 was considered significant. Results: In the 282 enrolled patients (75% male, 54 ± 12 years, BMI 27 ± 4 kg/m2, LVEF 27% ± 7%), the composite endpoint occurred in 24.4% during follow-up. Patients with higher BMI were older, and they had higher LVEF and serum sodium levels, as well as lower ventilatory efficiency (VE/VCO2) slope. VE/VCO2 and peak oxygen consumption (pVO2) were strong predictors of prognosis (p < 0.001). In univariable Cox regression analysis, higher BMI was associated with better outcomes (HR 0.940, CI 0.886 - 0.998, p 0.042). However, after adjusting for either VE/VCO2 slope or pVO2, the protective role of BMI disappeared. Survival benefit of BMI was not evident when patients were grouped according to cardiorespiratory fitness class (VE/VCO2, cut-off value 35, and pVO2, cut-off value 14 mL/kg/min). Conclusion: These results suggest that cardiorespiratory fitness outweighs the relationship between BMI and survival in patients with heart failure.

Prognostic Prediction of Cardiopulmonary Exercise Test Parameters in Heart Failure Patients with Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with increased mortality in heart failure (HF) patients. OBJECTIVE: To evaluate whether the risk of AF patients can be precisely stratified by relation with cardiopulmonary exercise test (CPET) cut-offs for heart transplantation (HT) selection. METHODS: Prospective evaluation of 274 consecutive HF patients with left ventricular ejection fraction ≤ 40%. The primary endpoint was a composite of cardiac death or urgent HT in 1-year follow-up. The primary endpoint was analysed by several CPET parameters for the highest area under the curve and for positive (PPV) and negative predictive value (NPV) in AF and sinus rhythm (SR) patients to detect if the current cut-offs for HT selection can precisely stratify the AF group. Statistical differences with a p-value <0.05 were considered significant. RESULTS: There were 51 patients in the AF group and 223 in the SR group. The primary outcome was higher in the AF group (17.6% vs 8.1%, p = 0.038). The cut-off value of pVO2 for HT selection showed a PPV of 100% and an NPV of 95.5% for the primary outcome in the AF group, with a PPV of 38.5% and an NPV of 94.3% in the SR group. The cut-off value of VE/VCO2 slope showed lower values of PPV (33.3%) and similar NPV (92.3%) to pVO2 results in the AF group. CONCLUSION: Despite the fact that AF carries a worse prognosis for HF patients, the current cut-off of pVO2 for HT selection can precisely stratify this high-risk group.

Comparative Genomics and Evolutionary Analysis of RNA-Binding Proteins of Burkholderia cenocepacia J2315 and Other Members of the B. cepacia Complex.

RNA-binding proteins (RBPs) are important regulators of cellular functions, playing critical roles on the survival of bacteria and in the case of pathogens, on their interaction with the host. RBPs are involved in transcriptional, post-transcriptional, and translational processes. However, except for model organisms like Escherichia coli, there is little information about the identification or characterization of RBPs in other bacteria, namely in members of the Burkholderia cepacia complex (Bcc). Bcc is a group of bacterial species associated with a poor clinical prognosis in cystic fibrosis patients. These species have some of the largest bacterial genomes, and except for the presence of two-distinct Hfq-like proteins, their RBP repertoire has not been analyzed so far. Using in silico approaches, we identified 186 conventional putative RBPs in Burkholderia cenocepacia J2315, an epidemic and multidrug resistant pathogen of cystic fibrosis patients. Here we describe the comparative genomics and phylogenetic analysis of RBPs present in multiple copies and predicted to play a role in transcription, protein synthesis, and RNA decay in Bcc bacteria. In addition to the two different Hfq chaperones, five cold shock proteins phylogenetically close to E. coli CspD protein and three distinct RhlE-like helicases could be found in the B. cenocepacia J2315 genome. No RhlB, SrmB, or DeaD helicases could be found in the genomes of these bacteria. These results, together with the multiple copies of other proteins generally involved in RNA degradation, suggest the existence, in B. cenocepacia and in other Bcc bacteria, of some extra and unexplored functions for the mentioned RBPs, as well as of alternative mechanisms involved in RNA regulation and metabolism in these bacteria.

Prognostic Prediction of Cardiopulmonary Exercise Test Parameters in Heart Failure Patients with Atrial Fibrillation / Previsão Prognóstica dos Parâmetros do Teste de Esforço Cardiopulmonar em Pacientes com Insuficiência Cardíaca e Fibrilação Atrial

Abstract Background: Atrial fibrillation (AF) is associated with increased mortality in heart failure (HF) patients. Objective: To evaluate whether the risk of AF patients can be precisely stratified by relation with cardiopulmonary exercise test (CPET) cut-offs for heart transplantation (HT) selection. Methods: Prospective evaluation of 274 consecutive HF patients with left ventricular ejection fraction ≤ 40%. The primary endpoint was a composite of cardiac death or urgent HT in 1-year follow-up. The primary endpoint was analysed by several CPET parameters for the highest area under the curve and for positive (PPV) and negative predictive value (NPV) in AF and sinus rhythm (SR) patients to detect if the current cut-offs for HT selection can precisely stratify the AF group. Statistical differences with a p-value <0.05 were considered significant. Results: There were 51 patients in the AF group and 223 in the SR group. The primary outcome was higher in the AF group (17.6% vs 8.1%, p = 0.038). The cut-off value of pVO2 for HT selection showed a PPV of 100% and an NPV of 95.5% for the primary outcome in the AF group, with a PPV of 38.5% and an NPV of 94.3% in the SR group. The cut-off value of VE/VCO2 slope showed lower values of PPV (33.3%) and similar NPV (92.3%) to pVO2 results in the AF group. Conclusion: Despite the fact that AF carries a worse prognosis for HF patients, the current cut-off of pVO2 for HT selection can precisely stratify this high-risk group.

Resumo Fundamento: A fibrilação atrial (FA) está associada ao aumento da mortalidade em pacientes com insuficiência cardíaca (IC). Objetivo: Avaliar se o risco de pacientes com FA pode ser estratificado com precisão em relação aos pontos de corte do teste de esforço cardiopulmonar (TECP) para seleção do transplante cardíaco (TC). Métodos: Avaliação prospectiva de 274 pacientes consecutivos com IC com fração de ejeção do ventrículo esquerdo ≤ 40%. O endpoint primário foi um composto de morte cardíaca ou TC urgente no seguimento de 1 ano. O endpoint primário foi analisado através de vários parâmetros do TECP para a maior área sob a curva e para o valor preditivo positivo (VPP) e negativo (VPN) em pacientes com FA e ritmo sinusal (RS) para detectar se os atuais pontos de corte para a seleção de TC podem estratificar com precisão o grupo com FA. Diferenças estatísticas com valor de p < 0,05 foram consideradas significativas. Resultados: Havia 51 pacientes no grupo de FA e 223 no grupo RS. O endpoint primário foi maior no grupo FA (17,6% vs. 8,1%, p = 0,038). O valor de corte de pVO2 para a seleção do TC mostrou um VPP de 100% e um VPN de 95,5% para o endpoint primário no grupo FA, com um VPP de 38,5% e um VPN de 94,3% no grupo RS. O valor de corte da inclinação VE/VCO2 apresentou valores mais baixos de VPP (33,3%) e valor semelhante de VPN (92,3%) aos resultados de pVO2 no grupo FA. Conclusões: Apesar do fato de a FA apresentar um pior prognóstico para os pacientes com IC, o atual ponto de corte de pVO2 para a seleção de TC pode estratificar com precisão esse grupo de alto risco.

Myocardial work improvement after sacubitril-valsartan therapy: a new echocardiographic parameter for a new treatment.

AIMS: Myocardial work is a new transthoracic echocardiogram (TTE) parameter that enhances the information provided through left ventricular (LV) global longitudinal strain (GLS). Nothing is known about the impact of sacubitril/valsartan (LCZ696) therapy on myocardial work parameters. The aim of this study was to evaluate the effects of LCZ696 on LV myocardial work in heart failure patients. METHODS: Prospective evaluation of chronic heart failure patients with LV ejection fraction of 40% or less despite optimized standard of care therapy, in which LCZ696 therapy was started and no other heart failure treatment was expected to change. TTE study was performed before and 6 months after LCZ696 therapy. A semiautomated analysis of LV GLS was made and myocardial work estimated using custom software of the GE Vivid E95 ultrasound system. RESULTS: Of the 42 patients, 35 (83.3%) completed the 6 months, follow-up, since 2 (4.8%) patients died and 5 (11.9%) discontinued treatment due to adverse events. Mean age was 58.6 ±â€Š11.1 years. TTE data showed a significant reduction in LV dimensions and atrial volumes, as well as an improvement in LV ejection fraction (29.3 vs. 35.2%, P = 0.001) and GLS (-7.0 vs. -8.9%, P = 0.001). Myocardial work had a significant increase in global constructive work (720.2 vs. 900.6 mmHg%, P = 0.016) and global work efficiency (78.6 vs. 86.6%, P = 0.027), with a nonsignificant decrease in global wasted work (150.2 vs. 136.8 mmHg%, P = 0.441) at 6 months. CONCLUSION: LCZ696 therapy was associated with signs of reverse remodelling by usual TTE parameters and LV myocardial work at 6 months, including an increase in global constructive work and work efficiency.

New insights into the immunoproteome of B. cenocepacia J2315 using serum samples from cystic fibrosis patients.

Bacteria of the Burkholderia cepacia complex (Bcc) are ubiquitous multidrug resistant organisms and opportunistic pathogens capable of causing life threatening lung infections among cystic fibrosis (CF) patients. No effective therapies are currently available to eradicate Bcc bacteria from CF patients, as these organisms are inherently resistant to the majority of clinically available antimicrobials. An immunoproteomics approach was used to identify Bcc proteins that stimulate the humoral immune response of the CF host, using bacterial cells grown under conditions mimicking the CF lung environment and serum samples from CF patients with a clinical record of Bcc infection. 24 proteins of the Bcc strain B. cenocepacia J2315 were identified as immunoreactive, 19 here reported as immunogenic for the first time. Ten proteins were predicted as extracytoplasmic, 9 of them being conserved in Bcc genomes. The immunogenic Bcc extracytoplasmic proteins are potential targets for development of novel therapeutic strategies and diagnostic tools to protect patients against the onset of chronic Bcc lung infections.

Prognostic value of VE/VCO2 slope in overweight heart failure patients.

BACKGROUND: A decreased hypercapnic ventilatory response of the overweight patients would lower the ventilation equivalent of carbon dioxide (VE/VCO2) slope but worsen prognosis. The aim of this study was to compare the prognostic ability of the VE/VCO2 slope and peak oxygen consumption (pVO2) between normal and overweight heart failure (HF) patients. METHODS: Prospective evaluation of ambulatory patients with reduced left ventricular ejection fraction who underwent baseline assessment with a cardiopulmonary exercise test. The primary endpoint was cardiac death or urgent heart transplantation in the 5-year period of follow-up. The predictive power of VE/VCO2 slope and pVO2 were compared (area under the curve (AUC) analysis and Hanley & McNeil test), in the subgroups of patients with body mass index (BMI) of 18.5-24.9 kg/m2 and ≥ 25 kg/m2. Statistical differences with a p value < 0.05 were considered significant. RESULTS: There were 270 enrolled patients, with a mean BMI of 27 ± 4 kg/m2. No differences between normal and overweight patients (38.0% vs 29.8%, P=0.170) were found during the 5-year period for the primary endpoint. The VE/VCO2 slope was non-inferior to pVO2 in both groups at 1, 3 and 5 years of follow-up. The comparison of VE/VCO2 slope between groups revealed a significant lower AUC at 3 (0.921 vs 0.787, P=0.022) and 5 years (0.898 vs 0.787, P=0.044) of follow-up for overweight patients. CONCLUSION: Despite VE/VCO2 slope provides a discriminative power at least as good as pVO2 for predicting adverse events in both normal and overweight HF patients, a significant lower predictive power was found in overweight patients.

Antiarrhythmic Effect of Sacubitril-Valsartan: Cause or Consequence of Clinical Improvement?

Sacubitril/Valsartan (LCZ696) reduced sudden cardiac death in the PARADIGM-HF trial. However, the mechanism by which LCZ696 reduces ventricular arrhythmias remains unclear. The aim of this study was to compare electrocardiographic (ECG) parameters and mechanical dispersion index, assessed by left ventricular (LV) global longitudinal strain (GLS), before and after LCZ696 therapy. We prospectively evaluated chronic Heart Failure (HF) patients with LV ejection fraction ≤40%, despite optimal medical and device therapy, in which LCZ696 therapy was started, while no additional HF treatment was expected to change. ECG and transthoracic echocardiographic data were gathered in the week before starting LCZ696 and at six months of therapy. A semiautomated analysis of LV GLS was performed and mechanical dispersion index was defined as the standard deviation from 16 time intervals corresponding to each LV segment. Of the 42 patients, 35 completed the six month follow-up, since two patients died and five discontinued treatment for adverse events. QTc interval (451.9 vs. 426.0 ms, p < 0.001), QRS duration (125.1 vs. 120.8 ms, p = 0.033) and mechanical dispersion index (88.4 vs. 78.1 ms, p = 0.036) were significantly reduced at six months. LCZ696 therapy is associated with a reduction in QTc interval, QRS duration and mechanical dispersion index as assessed by LV GLS.