[Cardiac compromise in patients recovered from COVID-19 without troponin elevation assessed by cardiac magnetic resonance imaging]. / Hallazgos en resonancia cardiaca post COVID-19 en pacientes sin elevación de troponinas.

Background: The disease caused by coronavirus (COVID-19) affects the cardiovascular system, whether by direct viral aggression or indirectly through systemic inflammation and multiple organ compromise. A widely used method to determine cardiac injury is troponin measurement. The aim of this study is to evaluate the prevalence of cardiac involvement (CINV) in a population recovered from COVID-19, referred to cardiac MRI (CMR), who did not present troponin elevation. Methods: There were 156 patients that recovered from COVID-19 and who did not present troponin elevation referred to CMR. CINV was considered to be the presence of: late gadolinium enhancement (LGE), edema, myocarditis, pericarditis, left ventricular systolic dysfunction (LVSD) and/or depressed right ventricular systolic dysfunction (RVSD). Results: Prevalence of CINV was 28.8%, being more frequent in men (p=0.002), in patients who required hospitalization (p=0.04) and in those who experienced non-mild cases of infection (p=0.007). RVSD (17.9%) and LVSD (13.4%) were the most frequent findings. The rate of myocarditis was 0.6%. LGE manifested in 7.1% of patients and its presence was related to less left ventricular ejection fraction (LVEF) (p=0.0001) and right ventricular ejection fraction (RVEF) (p=0.04). Conclusion: In patients who recovered from COVID-19, 28.8% of CINV was found. It was more frequent in men, in patients who required admission and in patients with cases of non-mild infection. The patients that presented LGE had less LVEF and RVSF.

Antecedentes: La enfermedad por coronavirus 2019 (COVID-19) afecta al sistema cardiovascular, ya sea mediante la agresión directa viral o indirectamente por medio de la inflamación sistémica y afectación multiorgánica. Las troponinas son ampliamente utilizadas para determinar lesión cardiaca. La finalidad de este estudio es evaluar la prevalencia de afectación cardiaca (ACARD) en una población recuperada de COVID-19, derivada a resonancia magnética cardiaca (RMC), sin elevación de troponinas al momento del estudio. Métodos: Ciento cincuenta y seis pacientes que se recuperaron de COVID-19 y que no presentaron elevación de troponinas fueron derivados a RMC. Se consideró ACARD a la presencia de: realce tardío de gadolinio (RTG), edema, miocarditis, pericarditis, deterioro de la función sistólica del ventrículo izquierdo (DFSVI) y/o depresión de la función sistólica del ventrículo derecho (DFSVD). Resultados: La prevalencia de ACARD fue del 28.8%, siendo más frecuente en hombres (p = 0.002), en pacientes que requirieron hospitalización (p = 0.04) y en aquellos que cursaron cuadro no leve de infección (p = 0.007). La DFSVD (17.9%) y la DFSVI (13.4%) fueron las hallazgos más frecuentes. La frecuencia de miocarditis fue del 0.6%. El RTG se manifestó en el 7.1% de los pacientes y se relacionó con menor fracción de eyección del ventrículo izquierdo (FEVI) (p = 0.0001) y derecho (FEVD) (p = 0.04). Conclusión: La prevalencia de ACARD fue del 28.8%. Esta es más frecuente en hombres, en pacientes que requirieron internación y que cursaron cuadros de infección no leve. La miocarditis presentó una prevalencia muy baja. Los pacientes que presentaron RTG tuvieron menor FEVI y FSVD.

Novel Purine Derivative ITH15004 Facilitates Exocytosis through a Mitochondrial Calcium-Mediated Mechanism.

Upon depolarization of chromaffin cells (CCs), a prompt release of catecholamines occurs. This event is triggered by a subplasmalemmal high-Ca2+ microdomain (HCMD) generated by Ca2+ entry through nearby voltage-activated calcium channels. HCMD is efficiently cleared by local mitochondria that avidly take up Ca2+ through their uniporter (MICU), then released back to the cytosol through mitochondrial Na+/Ca2+ exchanger (MNCX). We found that newly synthesized derivative ITH15004 facilitated the release of catecholamines triggered from high K+-depolarized bovine CCs. Such effect seemed to be due to regulation of mitochondrial Ca2+ circulation because: (i) FCCP-potentiated secretory responses decay was prevented by ITH15004; (ii) combination of FCCP and ITH15004 exerted additive secretion potentiation; (iii) such additive potentiation was dissipated by the MICU blocker ruthenium red (RR) or the MNCX blocker CGP37157 (CGP); (iv) combination of FCCP and ITH15004 produced both additive augmentation of cytosolic Ca2+ concentrations ([Ca2+]c) K+-challenged BCCs, and (v) non-inactivated [Ca2+]c transient when exposed to RR or CGP. On pharmacological grounds, data suggest that ITH15004 facilitates exocytosis by acting on mitochondria-controlled Ca2+ handling during K+ depolarization. These observations clearly show that ITH15004 is a novel pharmacological tool to study the role of mitochondria in the regulation of the bioenergetics and exocytosis in excitable cells.