Systematic review and meta-analysis of diagnostic test accuracy of ST-segment elevation for acute coronary occlusion

OBJECTIVE: To evaluate the diagnostic sensitivity and specificity of ST-segment elevation on a 12­lead ECG in detecting ACO across any coronary artery, challenging the current STEMI-NSTEMI paradigm. METHODS: Studies from MEDLINE and Scopus (2012-2023) comparing ECG findings with coronary angiograms were systematically reviewed and analyzed following PRISMA-DTA guidelines. QUADAS-2 assessed the risk of bias. STUDY SELECTION: Studies included focused on AMI patients and provided data enabling the construction of contingency tables for sensitivity and specificity calculation, excluding those with non-ACS conditions, outdated STEMI criteria, or a specific focus on bundle branch blocks or other complex diagnoses. Data were extracted systematically and pooled test accuracy estimates were computed using MetaDTA software, employing bivariate analyses for within- and between-study variation. The primary outcomes measured were the sensitivity and specificity of ST-segment elevation in detecting ACO. RESULTS: Three studies with 23,704 participants were included. The pooled sensitivity of ST-segment elevation for detecting ACO was 43.6% (95% CI: 34.7%-52.9%), indicating that over half of ACO cases may not exhibit ST-segment elevation criteria. The specificity was 96.5% (95% CI: 91.2%-98.7%). Additional analysis using the OMI-NOMI strategy showed improved sensitivity (78.1%, 95% CI: 62.7%-88.3%) while maintaining similar specificity (94.4%, 95% CI: 88.6%-97.3%). CONCLUSION: The findings reveal a significant diagnostic gap in the current STEMI-NSTEMI paradigm, with over half of ACO cases potentially lacking ST-segment elevation. The OMI-NOMI strategy could offer an improved diagnostic approach. The high heterogeneity and limited number of studies necessitate cautious interpretation and further research in diverse settings.

Systematic review and meta-analysis of diagnostic test accuracy of ST-segment elevation for acute coronary occlusion.

OBJECTIVE: To evaluate the diagnostic sensitivity and specificity of ST-segment elevation on a 12­lead ECG in detecting ACO across any coronary artery, challenging the current STEMI-NSTEMI paradigm. METHODS: Studies from MEDLINE and Scopus (2012-2023) comparing ECG findings with coronary angiograms were systematically reviewed and analyzed following PRISMA-DTA guidelines. QUADAS-2 assessed the risk of bias. STUDY SELECTION: Studies included focused on AMI patients and provided data enabling the construction of contingency tables for sensitivity and specificity calculation, excluding those with non-ACS conditions, outdated STEMI criteria, or a specific focus on bundle branch blocks or other complex diagnoses. Data were extracted systematically and pooled test accuracy estimates were computed using MetaDTA software, employing bivariate analyses for within- and between-study variation. The primary outcomes measured were the sensitivity and specificity of ST-segment elevation in detecting ACO. RESULTS: Three studies with 23,704 participants were included. The pooled sensitivity of ST-segment elevation for detecting ACO was 43.6% (95% CI: 34.7%-52.9%), indicating that over half of ACO cases may not exhibit ST-segment elevation. The specificity was 96.5% (95% CI: 91.2%-98.7%). Additional analysis using the OMI-NOMI strategy showed improved sensitivity (78.1%, 95% CI: 62.7%-88.3%) while maintaining similar specificity (94.4%, 95% CI: 88.6%-97.3%). CONCLUSION: The findings reveal a significant diagnostic gap in the current STEMI-NSTEMI paradigm, with over half of ACO cases potentially lacking ST-segment elevation. The OMI-NOMI strategy could offer an improved diagnostic approach. The high heterogeneity and limited number of studies necessitate cautious interpretation and further research in diverse settings.

Enhancing predictive accuracy of H2FPEF score in suspected HFpEF by incorporating left atrial reservoir strain

INTRODUCTION: Diagnosing HFpEF can be challenging, but the H2FPEF score is a valuable tool for clinical decision-making. Atrial fibrillation (AF) plays a significant role in this score, creating challenges for diagnosis in patients without AF or with paroxysmal AF. Left atrial reservoir strain (LArS) has emerged as a promising indicator for both AF and HFpEF. This study explores how incorporating LArS can enhance the predictive ability of the H2FPEF score for exercise capacity in outpatients with suspected HFpEF. METHODS: This cross-sectional study has a sample size of 283 patients with suspected HFpEF. We collected clinical and echocardiographic data and compared LArS values across different H2FPEF score categories. Additionally, we analyzed a subgroup of 129 patients who underwent a Cardiopulmonary Exercise Test (CPET) to evaluate the effectiveness of the H2FPEF score and LArS in predicting Peak VO2. To further comprehend the contribution of each feature in the performance of the H2FPEF score, we used Shapley Additive Explanations (SHAP) analysis. RESULTS: Most patients were female (63%), age of 60 (±12) years and LVEF of 60 (±5.2)%. Patients with low scores had a LArS of 32.6 (± 6.8)%, while those with moderate and high scores had probabilities of 26(± 8.2)% and 16 (±8.2)%, respectively (p<0.001). The H2FPEF score demonstrated an AUC of 0.74 (95% CI: 0.64-0.84) in predicting peak VO2, whereas LArS exhibited an AUC of 0.71 (95% CI: 0.62-0.80). Incorporating LArS into the score improved its performance, resulting in an AUC of 0.82 (95% CI: 0.75-0.89). The SHAP analysis revealed that LArS had a significant impact as the most important feature (Figure 1), while the importance of the atrial fibrillation criterion decreased significantly. CONCLUSIONS: Our findings show that integrating LArS improves the diagnostic performance of the H2FPEF score and offers a valuable alternative to the AF criterion within the H2FPEF algorithm.

Leveraging advanced ai algorithms for predicting outcomes in non-acute coronary syndrome chest pain patients

INTRODUCTION: Chest pain is often encountered in emergency rooms and the detection of acute coronary syndrome (ACS) is a major focus. However, a notable percentage of patients present with a diverse range of nonACS conditions. Accurately identifying the causes and outcomes of these cases can prevent unnecessary interventions, reduce healthcare costs, and optimize resource allocation. This study aims to explore how advanced AI algorithms can enhance risk assessment, refine classification, and predict outcomes in nonACS chest pain patients using conventional ECG analysis. METHODS: We studied 3458 nonACS patients referred to the Emergency Room at Instituto Dante Pazzanese de Cardiologia with chest pain. A total of 185 features, including sex, height, ECG diagnostic statements, and measures, were used. The predicted outcome was defined as hospitalization within 14 days and/or death (1 or 0). We employed the AutoGluon framework for feature engineering and early model selection. XGBoost, a tree-based model, was chosen as the architecture. Training and k-fold stratified cross-validation were performed using an oversampled balanced dataset, and evaluation metrics such as AUROC, specificity, and sensitivity were measured using the original data. RESULTS: In this study, 18.2% (630 patients) had a positive outcome. The sex distribution was comparable between outcome groups, with men accounting for 57-58% and women for 42-43%. Significant differences (p<0.01) were observed in ECG intervals (QRS, corrected QT, RR interval, PSP) between the groups. The AI model identified important diagnostic statements, including normal ECG (19.4), atrial fibrillation (7.4), left ventricular hypertrophy (7.1), Ischemic T-wave inversion in inferior leads (6.7), T-wave changes in inferior leads (5.9), and first-degree atrioventricular block (5.8). The AI model performed exceptionally well, with a sensitivity of 97.93%, specificity of 96.08%, and an AUROC of 0.97. CONCLUSIONS: The AI model demonstrated its ability to predict outcomes in patients with acute chest pain without ACS, making it an appealing tool for effective risk stratification. The early identification provided by the AI model presents an opportunity for timely intervention to mitigate adverse outcomes.

Associação entre o escore H2FPEF e as métricas do átrio esquerdo em pacientes com suspeita de insuficiência cardíaca com fração de ejeção preservada / Association between the H2FPEF score and left atrial metrics in patients with suspected heart failure with preserved ejection fraction

FUNDAMENTO: A insuficiência cardíaca com fração de ejeção preservada (ICFEP) é uma síndrome com fisiopatologia complexa e fenótipos heterogêneos. A incidência e prevalência dessa doença apresenta-se em ascensão, sendo seu diagnóstico desafiador. O escore H2FPEF condiciona fatores clínicos e ecocardiográficos para estimar a probabilidade de ICFEP. OBJETIVO: Avaliar a relação entre volume do átrio esquerdo (AE) indexado, o strain reservatório do AE ao escore H2FPEF. Delineamento e MÉTODOS: Trata-se de um estudo observacional com 283 pacientes com suspeita de ICFEP, no período de 2020 até 2022. Antes da inclusão, todos os pacientes foram avaliados para diagnósticos alternativos que poderiam mimetizar ICFEP. O critério de exclusão foi a fração de ejeção <50%. O escore H2FPEF foi calculado para todos os pacientes, e classificado de acordo com: baixo, intermediário ou alto risco. Os parâmetros ecocardiográficos avaliados foram volume de AE indexado e strain de AE. A análise estatística e a visualização dos dados foram realizadas no software Stata. O nível de significância adotado foi de 5%. A correlação entre as métricas do AE e o escore H2FPEF foi avaliada pelo teste de Pearson. RESULTADOS: Obteve-se 283 pacientes, sendo 52 pacientes com escore H2FPEF com risco baixo, 198 intermediário e 33 alto. Houve diferença significativa entre os grupos em relação as métricas do AE e o escore H2FPEF (p<0,05) (Tabela 1 e Figura 1). CONCLUSÃO: As métricas do AE são marcadores ecocardiográficos de disfunção diastólica e refletem os efeitos cumulativos das pressões de enchimento do ventrículo esquerdo. O aumento do AE e a redução do strain do AE na função reservatório foram associados ao aumento do escore H2FPEF. A avaliação desses parâmetros podem ser uma ferramenta adicional no diagnóstico de ICFEP. Palavras-chave: insuficiência cardíaca com fração de ejeção preservada; átrio esquerdo.

Diferenças relacionadas ao gênero de pacientes portadores de insuficiência cardíaca com fração de ejeção preservada: um estudo observacional / Gender-related differences in patients with heart failure with preserved ejection fraction: an observational study

INTRODUÇÃO: A insuficiência cardíaca com fração de ejeção preservada (ICFEP) é uma entidade emergente, principalmente na população feminina, onde a prevalência do gênero varia de 50 a 60%. Apesar desses valores, a representatividade desse grupo ainda é pequena em estudos clínicos, muitos questionamentos do entendimento dessa patologia e das características ecocardiográficas encontradas ainda são alvo de estudo. OBJETIVO: Avaliar as diferenças de características clínicas, ecocardiográficas e laboratoriais relacionadas ao gênero em uma população de pacientes com ICFEP possibilitando o melhor entendimento e manejo dessa população. MÉTODO: Estudo observacional retrospectivo em uma população de 300 pacientes em investigação de diferentes estágios de Insuficiência Cardíaca atendidos entre novembro de 2020 até novembro de 2022. Critérios de inclusão: (1) idade maior que 18 anos, (2) ecocardiograma transtorácico com FEVE ≥50% e (3) NTpro BNP ≥125pg/mL. Pacientes que apresentavam diagnósticos alternativos que simulassem ICFEP foram excluídos do trabalho. A coleta de dados incluiu: sinais vitais, antropometria, anamnese, exame físico, teste de caminhada, questionário de qualidade de vida e a realização do ecocardiograma transtorácico compreensivo. RESULTADOS: Obteve-se uma amostra de 91 pacientes, 65 (71%) do sexo feminino. Em relação aos critérios clínicos, observou-se maior pontuação no questionário de Minnesota (44 pontos versus 19 pontos, p=0,02) e maior grau NYHA de dispneia (p=0.023) no sexo feminino. Nos critérios ecocardiográficos, observou-se maior velocidade da onda E (75 cm/s versus 64,5 cm/s, p=0,004) e maior relação E/e´ (relação de 11 versus 9, p=0,004) no sexo feminino. No teste cardiopulmonar, observou-se menores valores de VO2 máximo no sexo feminino (19,7 versus 24, p=0.001). Observou-se que nas mulheres ocorreu predomínio da disfunção diastólica grau II, presente em 24 mulheres (56%) e a disfunção diastólica grau I foi predominante no sexo masculino, 13 homens (72%). CONCLUSÃO: No atual estudo foi possível observar diferenças substanciais entre gêneros em relação a características clínicas, capacidade de exercício e variáveis ecocardiográficas em uma população com diagnóstico de ICFEP. Tais achados reforçam a necessidade da aplicação de conceitos de medicina de precisão/personalizada sobre os atuais critérios clínicos e ecocardiográficos para abordagem de pacientes com ICFEP.

Bendopneia é um sinal semiológico associado a baixa reserva diastólica em pacientes insuficiência cardíaca com fração de ejeção preservada / Bendopnea is a semiological sign associated with low diastolic reserve in heart failure patients with preserved ejection fraction

INTRODUÇÃO: A Insuficiência Cardíaca com Fração de Ejeção Preservada (ICFEP) é uma condição prevalente na população geral, cujo diagnóstico pode ser desafiador. Atualmente, há uma escassez de dados sobre quais aspectos do exame clínico são mais relevantes para o diagnóstico. MÉTODOS: Foram avaliados pacientes com suspeita de ICFEP em um ambulatório de hospital terciário de Cardiologia. A bendopneia foi explorada por um operador experiente através da ântero-flexão do tórax do paciente em posição sentada por tempo>30s. Casos com elevação da frequência respiratória com sensação de dispneia foram considerados positivos. Em caso de dúvida um segundo examinador era consultado. Casos duvidosos foram considerados negativos. A reserva diastólica foi acessada utilizando a ecocardiografia com Doppler tissular para acessar os valores de e' lateral em condições de repouso e durante um teste de pré-carga provocado pela elevação passiva de membros inferiores. Ademais, realizou-se cálculo do escore H2FPEF para diagnóstico de ICFEP. Estes grupos foram comparados através das diferenças das médias do escore H2FPEF estimada pelo teste t não pareado com nível de significância (a) de 95%. Finalmente, realizou-se regressão linear para comparação dos beta-coeficientes (b) da variação do e lateral repouso e durante a elevação de membros inferiores. Desta forma, o valor do b coeficiente será diretamente proporcional à reserva diastólica. RESULTADOS: Obteve-se 305 pacientes, dos quais 149 com bendopneia presente ao exame físico. O grupo sem bendopneia apresentou um H2FPEF de 2.7(±0.16), enquanto com pacientes com dispneia apresentaram um escore de 3.8(±0.16). Essa diferença entre os grupos apresentou significância estatística(p<0,001) (Figura 1). O teste de reserva diastólica foi realizado em 92 pacientes. O grupo sem bendopneia apresentou b=0.77(IC 95%:0.64;0.89), enquanto aqueles com bendopneia apresentaram um valor mais baixo de reserva diastólica com b=0.53 (IC 95%:0.32;0.74) (Figura 2). CONCLUSÕES: A bendopneia é um sinal semiológico útil para diagnóstico de ICFEP e está associado a baixa reserva diastólica.

Associação entre ângulo de fase e o SCORE HFA-PEFF de pacientes com ICFEP / Association between phase angle and HFA-PEFF SCORE in patients with HFpEF

INTRODUÇÃO: A insuficiência cardíaca com fração de ejeção preservada (ICFEp), já é responsável por mais da metade de todas as internações hospitalares por insuficiência cardíaca (IC). Pesquisas mostram que na população geral com idade >60 anos, 4,9% são diagnosticados com ICFEP e espera-se um aumento à medida que as pessoas vivem mais e a obesidade e diabetes tornam-se mais comuns. Heart Failure Association (HFA) da European Society of Cardiology (ESC) publicou uma recomendação para o diagnóstico da insuficiência cardíaca com fração de ejeção preservada ICFEp, trata-se do score (HFA-PEFF).A utilização de índices prognósticos no paciente com IC permite uma avaliação quanto à gravidade e ao impacto da doença na sobrevida do seu portador, além do monitoramento adequado da evolução clínica do mesmo. Nesse contexto, o exame de bioimpedância elétrica (BIA) vem sendo adotado para a avaliação de prognóstico. A partir da BIA obtém-se o ângulo de fase (AF), que expressa o equilíbrio entre os espaços intra e extracelulares, e tem sido relacionado com o sucesso, sobrevivência e evolução da doença, possibilitando não só monitorar a resposta do paciente ao tratamento em curso, mas reprogramar o cuidado prestado com a possibilidade de modificar o prognóstico. OBJETIVO: Verificar associação entre o AF a classificação dos pacientes com ICFEp, de acordo com o score HFA-PEFF. MÉTODO: Estudo transversal com 132 pacientes que foram avaliados e classificados através do score HFA-PEFF em baixa, intermediária ou alta probabilidade de ICFEp. Foram obtidos dados antropométricos e realizaram o exame de BIA para avaliação do AF. RESULTADOS: A média etária dos avaliados foi de 63±12 anos, sendo 65,15% (n= 86) do sexo feminino. Segundo a probabilidade de ICFEP pelo score HFA-PEFF, foram classificados em Baixa (n=39), Intermediário (n=57) e Alta (n=36). Em relação ao AF, houve associação entre pacientes com alta probabilidade de ICFEP e AF significativamente menores do que aqueles com probabilidades baixa e intermediária. CONCLUSÃO: O menor AF verificado foi encontrado nos pacientes com alta probabilidade de ICFEP segundo o score HFA-PEFF, sugerindo como um potencial marcador prognóstico na evolução da ICFEp.

Mechanical dispersion is a superior echocardiographic feature to predict exercise capacity in preclinical and overt heart failure with preserved ejection fraction.

BACKGROUND: Heart Failure with Preserved Ejection Fraction (HFpEF) is a syndrome characterized by different degrees of exercise intolerance, which leads to poor quality of life and prognosis. Recently, the European score (HFA-PEFF) was proposed to standardize the diagnosis of HFpEF. Even though Global Longitudinal Strain (GLS) is a component of HFA-PEFF, the role of other strain parameters, such as Mechanical Dispersion (MD), has yet to be studied. In this study, we aimed to compare MD and other features from the HFA-PEFF according to their association with exercise capacity in an outpatient population of subjects at risk or suspected HFpEF. METHODS: This is a single-center cross-sectional study performed in an outpatient population of 144 subjects with a median age of 57 years, 58% females, referred to the Echocardiography and Cardiopulmonary Exercise Test to investigate HFpEF. RESULTS: MD had a higher correlation to Peak VO2 (r=-0.43) when compared to GLS (r=-0.26), MD presented a significant correlation to Ventilatory Anaerobic Threshold (VAT) (r=-0.20; p = 0.04), while GLS showed no correlation (r=-0.14; p = 0.15). Neither MD nor GLS showed a correlation with the time to recover VO2 after exercise (T1/2). In Receiver Operator Characteristic (ROC) analysis, MD presented superior performance to GLS to predict Peak VO2 (AUC: 0.77 vs. 0.62), VAT (AUC: 0.61 vs. 0.57), and T1/2 (AUC: 0.64 vs. 0.57). Adding MD to HFA-PEFF improved the model performance (AUC from 0.77 to 0.81). CONCLUSION: MD presented a higher association with Peak VO2 when compared to GLS and most features from the HFA-PEFF. Adding MD to the HFA-PEFF improved the model performance.

Afterload increase challenge unmasks systolic abnormalities in heart failure with preserved ejection fraction.

BACKGROUND: Provocative maneuvers have the potential to overcome the low sensitivity of resting echocardiography and biomarkers in the detection of heart failure with preserved ejection fraction (HFpEF). We investigate the mechanical response of the left ventricle to an afterload challenge in patients with preclinical and early-stage HFpEF (es-HFpEF). METHODS: Three groups of patients (non-HFpEF - n = 42, pre-HFpEF - n = 43, and es-HFpEF - n = 39) underwent echocardiography at rest and during an afterload challenge induced by handgrip maneuver combined with pneumatic constriction of limbs. RESULTS: Patients in the non-HF group displayed a median ΔLPSS = -4% (IQR: -10%, +2%), LPSS rest<16% in 3/42(7%) and LPSS stress<16% in 6/43(14%). Subjects in the pre-HFpEF group displayed median ΔLPSS = -3% (IQR: -10%, +5%) LPSS rest<16% in 13/43(30%) and LPSS stress<16% in 19/43 (44%). 11/43 (25%) subjects in this group increased at least one absolute point in LPSS during stress. Patients in es-HFpEF group displayed a median ΔLPSS = -10% (IQR: -18%, -1%), LPSS rest<16% in 15/39(38%) and LPSS stress<16% in 25/39(64%). Changes in LPSS (ΔLPSS) were significantly greater in es-HFpEF than pre-HFpEF (p = 0.022). In multivariate analysis, this group effect was maintained after adjustment of the LPSS for systolic blood pressure, use of ß-blockers, LV mass, RWT, age, and sex. CONCLUSION: Our data suggest that patients with HFpEF have a marked decrease in peak strain during acute pressure overload. Longitudinal studies are needed to test and compare the clinical impact of each pattern in early and long-term follow-ups.

Afterload increase challenge unmasks systolic abnormalities in heart failure with preserved ejection fraction

BACKGROUND: Provocative maneuvers have the potential to overcome the low sensitivity of resting echocardiography and biomarkers in the detection of heart failure with preserved ejection fraction (HFpEF). We investigate the mechanical response of the left ventricle to an afterload challenge in patients with preclinical and early-stage HFpEF (es-HFpEF). METHODS: Three groups of patients (non-HFpEF - n = 42, pre-HFpEF - n = 43, and es-HFpEF - n = 39) underwent echocardiography at rest and during an afterload challenge induced by handgrip maneuver combined with pneumatic constriction of limbs. RESULTS: Patients in the non-HF group displayed a median ΔLPSS = -4% (IQR: -10%, +2%), LPSS rest<16% in 3/42(7%) and LPSS stress<16% in 6/43(14%). Subjects in the pre-HFpEF group displayed median ΔLPSS = -3% (IQR: -10%, +5%) LPSS rest<16% in 13/43(30%) and LPSS stress<16% in 19/43 (44%). 11/43 (25%) subjects in this group increased at least one absolute point in LPSS during stress. Patients in es-HFpEF group displayed a median ΔLPSS = -10% (IQR: -18%, -1%), LPSS rest<16% in 15/39(38%) and LPSS stress<16% in 25/39(64%). Changes in LPSS (ΔLPSS) were significantly greater in es-HFpEF than pre-HFpEF (p = 0.022). In multivariate analysis, this group effect was maintained after adjustment of the LPSS for systolic blood pressure, use of ß-blockers, LV mass, RWT, age, and sex. CONCLUSION: Our data suggest that patients with HFpEF have a marked decrease in peak strain during acute pressure overload. Longitudinal studies are needed to test and compare the clinical impact of each pattern in early and long-term follow-ups.

Mechanical dispersion is a superior echocardiographic feature to predict exercise capacity in preclinical and overt heart failure with preserved ejection fraction

BACKGROUND: Heart Failure with Preserved Ejection Fraction (HFpEF) is a syndrome characterized by different degrees of exercise intolerance, which leads to poor quality of life and prognosis. Recently, the European score (HFA-PEFF) was proposed to standardize the diagnosis of HFpEF. Even though Global Longitudinal Strain (GLS) is a component of HFA-PEFF, the role of other strain parameters, such as Mechanical Dispersion (MD), has yet to be studied. In this study, we aimed to compare MD and other features from the HFA-PEFF according to their association with exercise capacity in an outpatient population of subjects at risk or suspected HFpEF. METHODS: This is a single-center cross-sectional study performed in an outpatient population of 144 subjects with a median age of 57 years, 58% females, referred to the Echocardiography and Cardiopulmonary Exercise Test to investigate HFpEF. RESULTS: MD had a higher correlation to Peak VO2 (r=-0.43) when compared to GLS (r=-0.26), MD presented a significant correlation to Ventilatory Anaerobic Threshold (VAT) (r=-0.20; p = 0.04), while GLS showed no correlation (r=-0.14; p = 0.15). Neither MD nor GLS showed a correlation with the time to recover VO2 after exercise (T1/2). In Receiver Operator Characteristic (ROC) analysis, MD presented superior performance to GLS to predict Peak VO2 (AUC: 0.77 vs. 0.62), VAT (AUC: 0.61 vs. 0.57), and T1/2 (AUC: 0.64 vs. 0.57). Adding MD to HFA-PEFF improved the model performance (AUC from 0.77 to 0.81). CONCLUSION: MD presented a higher association with Peak VO2 when compared to GLS and most features from the HFA-PEFF. Adding MD to the HFA-PEFF improved the model performance.

Metformin acts in the gut and induces gut-liver crosstalk.

Metformin is the most prescribed drug for DM2, but its site and mechanism of action are still not well established. Here, we investigated the effects of metformin on basolateral intestinal glucose uptake (BIGU), and its consequences on hepatic glucose production (HGP). In diabetic patients and mice, the primary site of metformin action was the gut, increasing BIGU, evaluated through PET-CT. In mice and CaCo2 cells, this increase in BIGU resulted from an increase in GLUT1 and GLUT2, secondary to ATF4 and AMPK. In hyperglycemia, metformin increased the lactate (reducing pH and bicarbonate in portal vein) and acetate production in the gut, modulating liver pyruvate carboxylase, MPC1/2, and FBP1, establishing a gut-liver crosstalk that reduces HGP. In normoglycemia, metformin-induced increases in BIGU is accompanied by hypoglycemia in the portal vein, generating a counter-regulatory mechanism that avoids reductions or even increases HGP. In summary, metformin increases BIGU and through gut-liver crosstalk influences HGP.

Discovery and structural characterization of chicoric acid as a SARS-CoV-2 nucleocapsid protein ligand and RNA binding disruptor.

The nucleocapsid (N) protein plays critical roles in coronavirus genome transcription and packaging, representing a key target for the development of novel antivirals, and for which structural information on ligand binding is scarce. We used a novel fluorescence polarization assay to identify small molecules that disrupt the binding of the N protein to a target RNA derived from the SARS-CoV-2 genome packaging signal. Several phenolic compounds, including L-chicoric acid (CA), were identified as high-affinity N-protein ligands. The binding of CA to the N protein was confirmed by isothermal titration calorimetry, 1H-STD and 15N-HSQC NMR, and by the crystal structure of CA bound to the N protein C-terminal domain (CTD), further revealing a new modulatory site in the SARS-CoV-2 N protein. Moreover, CA reduced SARS-CoV-2 replication in cell cultures. These data thus open venues for the development of new antivirals targeting the N protein, an essential and yet underexplored coronavirus target.

Personalized medicine using omics approaches in acute respiratory distress syndrome to identify biological phenotypes.

In the last decade, research on acute respiratory distress syndrome (ARDS) has made considerable progress. However, ARDS remains a leading cause of mortality in the intensive care unit. ARDS presents distinct subphenotypes with different clinical and biological features. The pathophysiologic mechanisms of ARDS may contribute to the biological variability and partially explain why some pharmacologic therapies for ARDS have failed to improve patient outcomes. Therefore, identifying ARDS variability and heterogeneity might be a key strategy for finding effective treatments. Research involving studies on biomarkers and genomic, metabolomic, and proteomic technologies is increasing. These new approaches, which are dedicated to the identification and quantitative analysis of components from biological matrixes, may help differentiate between different types of damage and predict clinical outcome and risk. Omics technologies offer a new opportunity for the development of diagnostic tools and personalized therapy in ARDS. This narrative review assesses recent evidence regarding genomics, proteomics, and metabolomics in ARDS research.

Machine learning-driven serum metabolomics: insights into the transition to early-stage heart failure with preserved ejection fraction

Introduction: Metabolomics has emerged as a powerful tool in providing readouts of early disease states before clinical manifestation. Here we used the predictive power of Unsupervised Hierarchical Clustering Analysis (UHCA) and Automated Machine Learning (AutoML) algorithms to identify serum metabolic panels in a population at risk of developing HFpEF. Methods: We studied 215 subjects staged as non-HF, pre-HFpEF and early-stage HFpEF(es-HFpEF). We evaluated clinical, laboratory, echocardiographic, and NMR-based metabolomics of blood serum data. UHCA and AutoML were used to explore metabolic fingerprints potentially related to clinical features or HFpEF. We used Metabolite Set Enrichment Analysis to explore biochemical pathways. Results: The UHCA identified three major patients (P) and two metabolites (M) clusters (Figure). The P clusters were associated with HFpEF stages, cardiac remodeling, diastolic dysfunction, and sex (Pearson Chi-square, p < 0.05) and M clusters with glycine and serine metabolism and urea cycle pathways (FDR-adjusted p-value < 0.002). Considering non-HFpEF and es-HFpEF groups, AUROC mean for feature subset combinations was 0.897 and the highest AUROC (0.995) combined metabolites, clinical, laboratory and echo features. Of the 64 models trained that included metabolites as input, serine (25), uridine (17), 2-oxoglutarate (14), citrate (14), 2-aminobutyrate (13) and taurine (13) were observed more frequently with feature importance value greater than zero. The metabolites with higher sum values of feature importance were serine (0.173), uridine (0.131), 2-aminobutyrate (0.123), choline (0.098) and dimethylamine (0.087). Conclusions: This study revealed characteristic metabolite profiles in the sera of patients at risk of developing HFpEF. These metabolite panels can add information for classificatory algorithms development and contribute to the understanding of HFpEF pathophysiology.

Identification and characterization of the anti-SARS-CoV-2 activity of cationic amphiphilic steroidal compounds.

The ongoing COVID-19 pandemic caused a significant loss of human lives and a worldwide decline in quality of life. Treatment of COVID-19 patients is challenging, and specific treatments to reduce COVID-19 aggravation and mortality are still necessary. Here, we describe the discovery of a novel class of epiandrosterone steroidal compounds with cationic amphiphilic properties that present antiviral activity against SARS-CoV-2 in the low micromolar range. Compounds were identified in screening campaigns using a cytopathic effect-based assay in Vero CCL81 cells, followed by hit compound validation and characterization. Compounds LNB167 and LNB169 were selected due to their ability to reduce the levels of infectious viral progeny and viral RNA levels in Vero CCL81, HEK293, and HuH7.5 cell lines. Mechanistic studies in Vero CCL81 cells indicated that LNB167 and LNB169 inhibited the initial phase of viral replication through mechanisms involving modulation of membrane lipids and cholesterol in host cells. Selection of viral variants resistant to steroidal compound treatment revealed single mutations on transmembrane, lipid membrane-interacting Spike and Envelope proteins. Finally, in vivo testing using the hACE2 transgenic mouse model indicated that SARS-CoV-2 infection could not be ameliorated by LNB167 treatment. We conclude that anti-SARS-CoV-2 activities of steroidal compounds LNB167 and LNB169 are likely host-targeted, consistent with the properties of cationic amphiphilic compounds that modulate host cell lipid biology. Although effective in vitro, protective effects were cell-type specific and did not translate to protection in vivo, indicating that subversion of lipid membrane physiology is an important, yet complex mechanism involved in SARS-CoV-2 replication and pathogenesis.

Randomized clinical trial of BCG vaccine in patients with convalescent COVID-19: Clinical evolution, adverse events, and humoral immune response.

BACKGROUND: The Bacillus Calmette-Guérin (BCG) vaccine may confer cross-protection against viral diseases in adults. This study evaluated BCG vaccine cross-protection in adults with convalescent coronavirus disease 2019 (COVID-19). METHOD: This was a multicenter, prospective, randomized, placebo-controlled, double-blind phase III study (ClinicalTrials.gov: NCT04369794). SETTING: University Community Health Center and Municipal Outpatient Center in South America. PATIENTS: a total of 378 adult patients with convalescent COVID-19 were included. INTERVENTION: single intradermal BCG vaccine (n = 183) and placebo (n = 195). MEASUREMENTS: the primary outcome was clinical evolution. Other outcomes included adverse events and humoral immune responses for up to 6 months. RESULTS: A significantly higher proportion of BCG patients with anosmia and ageusia recovered at the 6-week follow-up visit than placebo (anosmia: 83.1% vs. 68.7% healed, p = 0.043, number needed to treat [NNT] = 6.9; ageusia: 81.2% vs. 63.4% healed, p = 0.032, NNT = 5.6). BCG also prevented the appearance of ageusia in the following weeks: seven in 113 (6.2%) BCG recipients versus 19 in 126 (15.1%) placebos, p = 0.036, NNT = 11.2. BCG did not induce any severe or systemic adverse effects. The most common and expected adverse effects were local vaccine lesions, erythema (n = 152; 86.4%), and papules (n = 111; 63.1%). Anti-severe acute respiratory syndrome coronavirus 2 humoral response measured by N protein immunoglobulin G titer and seroneutralization by interacting with the angiotensin-converting enzyme 2 receptor suggest that the serum of BCG-injected patients may neutralize the virus at lower specificity; however, the results were not statistically significant. CONCLUSION: BCG vaccine is safe and offers cross-protection against COVID-19 with potential humoral response modulation. LIMITATIONS: No severely ill patients were included.

Structural dynamics of SARS-CoV-2 nucleocapsid protein induced by RNA binding.

The nucleocapsid (N) protein of the SARS-CoV-2 virus, the causal agent of COVID-19, is a multifunction phosphoprotein that plays critical roles in the virus life cycle, including transcription and packaging of the viral RNA. To play such diverse roles, the N protein has two globular RNA-binding modules, the N- (NTD) and C-terminal (CTD) domains, which are connected by an intrinsically disordered region. Despite the wealth of structural data available for the isolated NTD and CTD, how these domains are arranged in the full-length protein and how the oligomerization of N influences its RNA-binding activity remains largely unclear. Herein, using experimental data from electron microscopy and biochemical/biophysical techniques combined with molecular modeling and molecular dynamics simulations, we show that, in the absence of RNA, the N protein formed structurally dynamic dimers, with the NTD and CTD arranged in extended conformations. However, in the presence of RNA, the N protein assumed a more compact conformation where the NTD and CTD are packed together. We also provided an octameric model for the full-length N bound to RNA that is consistent with electron microscopy images of the N protein in the presence of RNA. Together, our results shed new light on the dynamics and higher-order oligomeric structure of this versatile protein.

Nitazoxanide in Patients Hospitalized With COVID-19 Pneumonia: A Multicentre, Randomized, Double-Blind, Placebo-Controlled Trial.

Background: Nitazoxanide exerts antiviral activity in vitro and in vivo and anti-inflammatory effects, but its impact on patients hospitalized with COVID-19 pneumonia is uncertain. Methods: A multicentre, randomized, double-blind, placebo-controlled trial was conducted in 19 hospitals in Brazil. Hospitalized adult patients requiring supplemental oxygen, with COVID-19 symptoms and a chest computed tomography scan suggestive of viral pneumonia or positive RT-PCR test for COVID-19 were enrolled. Patients were randomized 1:1 to receive nitazoxanide (500 mg) or placebo, 3 times daily, for 5 days, and were followed for 14 days. The primary outcome was intensive care unit admission due to the need for invasive mechanical ventilation. Secondary outcomes included clinical improvement, hospital discharge, oxygen requirements, death, and adverse events within 14 days. Results: Of the 498 patients, 405 (202 in the nitazoxanide group and 203 in the placebo group) were included in the analyses. Admission to the intensive care unit did not differ between the groups (hazard ratio [95% confidence interval], 0.68 [0.38-1.20], p = 0.179); death rates also did not differ. Nitazoxanide improved the clinical outcome (2.75 [2.21-3.43], p < 0.0001), time to hospital discharge (1.37 [1.11-1.71], p = 0.005), and reduced oxygen requirements (0.77 [0.64-0.94], p = 0.011). C-reactive protein, D-dimer, and ferritin levels were lower in the nitazoxanide group than the placebo group on day 7. No serious adverse events were observed. Conclusions: Nitazoxanide, compared with placebo, did not prevent admission to the intensive care unit for patients hospitalized with COVID-19 pneumonia. Clinical Trial Registration: Brazilian Registry of Clinical Trials (REBEC) RBR88bs9x; ClinicalTrials.gov, NCT04561219.