Current methods for the isolation of extracellular vesicles.

Extracellular vesicles (EVs), including microvesicles and exosomes, are nano- to micron-sized vesicles, which may deliver bioactive cargos that include lipids, growth factors and their receptors, proteases, signaling molecules, as well as mRNA and non-coding RNA, released from the cell of origin, to target cells. EVs are released by all cell types and likely induced by mechanisms involved in oncogenic transformation, environmental stimulation, cellular activation, oxidative stress, or death. Ongoing studies investigate the molecular mechanisms and mediators of EVs-based intercellular communication at physiological and oncogenic conditions with the hope of using this information as a possible source for explaining physiological processes in addition to using them as therapeutic targets and disease biomarkers in a variety of diseases. A major limitation in this evolving discipline is the hardship and the lack of standardization for already challenging techniques to isolate EVs. Technical advances have been accomplished in the field of isolation with improving knowledge and emerging novel technologies, including ultracentrifugation, microfluidics, magnetic beads and filtration-based isolation methods. In this review, we will discuss the latest advances in methods of isolation methods and production of clinical grade EVs as well as their advantages and disadvantages, and the justification for their support and the challenges that they encounter.

Recurrent Chest Pain After COVID-19: Diagnostic Utility of Cardiac Magnetic Resonance Imaging.

We report a case of myocarditis in an adult patient with recent coronavirus disease 2019 (COVID-19) infection presenting as recurrent ST-segment elevation, mimicking coronary vasospasm. This case highlights the wide range of presentations of COVID-19-related myocarditis. The novel teaching point is that COVID-19 myocarditis can present with acute manifestations such as chest pain and transient ST-segment elevation even several weeks after complete recovery from the initial infection. Cardiac magnetic resonance imaging should be considered in patients with chest pain syndromes and angiographically normal coronary arteries, as the presence of late gadolinium enhancement and a high T2 signal can be diagnostic. Follow-up cardiac magnetic resonance imaging may be used to assess resolution.

Nous présentons un cas de myocardite chez un patient adulte infecté par le nouveau coronavirus (COVID-19) qui s'est traduit par une élévation récurrente du segment ST évoquant un vasospasme coronarien. Ce cas illustre le large éventail de tableaux cliniques de la myocardite associée à la COVID-19. Le nouveau point à retenir est que la myocardite associée à la COVID-19 peut se traduire par des manifestations aiguës telles que la douleur thoracique l'élévation transitoire du segment ST, même plusieurs semaines après le rétablissement complet de l'infection initiale. L'imagerie cardiaque par résonance magnétique devrait être envisagée chez les patients qui ont des syndromes de douleur thoracique et des artères coronariennes normales à l'angiographie, puisque la présence d'un rehaussement tardif après injection de gadolinium et d'un signal élevé en T2 peut servir à poser le diagnostic. Le suivi en imagerie cardiaque par résonance magnétique peut être utilisé pour évaluer la résolution.

Incidence and Clinical Significance of New-Onset Device-Detected Atrial Tachyarrhythmia: A Meta-Analysis.

BACKGROUND: Despite the clear association between atrial fibrillation and risk for thromboembolic events (TEs), the clinical significance of new-onset device-detected atrial tachyarrhythmia (DDAT) and TE remains disputed. We aimed to determine the risk of TE in patients with new-onset DDAT. METHODS AND RESULTS: The OVID Medline, Cochrane, and Scopus databases (inception to November 2016) were searched. Randomized controlled trials, prospective, or retrospective studies of pacemaker or defibrillator patients reporting incidence of DDAT were selected. Summary statistics were used for analysis. Of 4893 reports identified, 28 studies following 24 984 patients were included: average age 69.9 years, 34.7% women, mean study duration 21.8±18.6 months. New-onset DDAT was observed in 23% of patients. Among 9 studies (n=8181) reporting TE, the absolute incidence was 2.1%. TE risk was significantly greater among patients with new-onset DDAT (relative risk [RR], 2.88; 95% CI, 1.79-4.64; P<0.001). TE risk was correlated with DDAT duration, with an increased risk associated with DDAT ≥5 minutes (RR, 3.86; 95% CI, 2.04-7.30; P<0.001) compared with <1 minute (RR, 1.77; 95% CI, 1.15-2.74; P=0.01). Notably, the risk of TE was also increased in patients with adjudicated atrial electrograms (RR, 3.60; 95% CI, 2.06-6.30; P<0.001) compared with nonadjudicated electrograms (RR, 2.05; 95% CI, 1.06-3.97; P=0.03), even when lower mean thresholds for detection were used. CONCLUSIONS: New-onset DDAT is common, affecting close to one quarter of all patients with implanted pacemakers or defibrillators. Adjudication of atrial electrograms further identifies at-risk patients, even when relatively short detection thresholds are used.