Background and PurposeIn 30–40% of hypertrophic cardiomyopathy (HCM) patients, symptomatic left ventricular (LV) outflow gradients develop only during exercise due to catecholamine‐induced LV hypercontractility (inducible obstruction). Negative inotropic pharmacological options are limited to β‐blockers or disopyramide, with low efficacy and tolerability. We assessed the potential of late sodium current (INaL)‐inhibitors to treat inducible obstruction in HCM.Experimental ApproachThe electrophysiological and mechanical responses to β‐adrenoceptor stimulation were studied in human myocardium from HCM and control patients. Effects of INaL‐inhibitors (ranolazine and GS‐967) in HCM samples were investigated under conditions simulating rest and exercise.Key ResultsIn cardiomyocytes and trabeculae from 18 surgical septal samples of patients with obstruction, the selective INaL‐inhibitor GS‐967 (0.5 μM) hastened twitch kinetics, decreased diastolic [Ca2+] and shortened action potentials, matching the effects of ranolazine (10μM). Mechanical responses to isoprenaline (inotropic and lusitropic) were comparable in HCM and control myocardium. However, isoprenaline prolonged action potentials in HCM myocardium, while it shortened them in controls. Unlike disopyramide, neither GS‐967 nor ranolazine reduced force at rest. However, in the presence of isoprenaline, they reduced Ca2+‐transient amplitude and twitch tension, while the acceleration of relaxation was maintained. INaL‐inhibitors were more effective than disopyramide in reducing contractility during exercise. Finally, INaL‐inhibitors abolished arrhythmias induced by isoprenaline.Conclusions and ImplicationsRanolazine and GS‐967 reduced septal myocardium tension during simulated exercise in vitro and therefore have the potential to ameliorate symptoms caused by inducible obstruction in HCM patients, with some advantages over disopyramide and β‐blockers.

Background— Current therapies are ineffective in preventing the development of cardiac phenotype in young carriers of mutations associated with hypertrophic cardiomyopathy (HCM). Ranolazine, a late Na+ current blocker, reduced the electromechanical dysfunction of human HCM myocardium in vitro. Methods and Results— To test whether long-term treatment prevents cardiomyopathy in vivo, transgenic mice harboring the R92Q troponin-T mutation and wild-type littermates received an oral lifelong treatment with ranolazine and were compared with age-matched vehicle-treated animals. In 12-months-old male R92Q mice, ranolazine at therapeutic plasma concentrations prevented the development of HCM-related cardiac phenotype, including thickening of the interventricular septum, left ventricular volume reduction, left ventricular hypercontractility, diastolic dysfunction, left-atrial enlargement and left ventricular fibrosis, as evaluated in vivo using echocardiography and magnetic resonance. Left ventricular cardiomyocytes from vehicle-treated R92Q mice showed marked excitation–contraction coupling abnormalities, including increased diastolic [Ca2+] and Ca2+ waves, whereas cells from treated mutants were undistinguishable from those from wild-type mice. Intact trabeculae from vehicle-treated mutants displayed inotropic insufficiency, increased diastolic tension, and premature contractions; ranolazine treatment counteracted the development of myocardial mechanical abnormalities. In mutant myocytes, ranolazine inhibited the enhanced late Na+ current and reduced intracellular [Na+] and diastolic [Ca2+], ultimately preventing the pathological increase of calmodulin kinase activity in treated mice. Conclusions— Owing to the sustained reduction of intracellular Ca2+ and calmodulin kinase activity, ranolazine prevented the development of morphological and functional cardiac phenotype in mice carrying a clinically relevant HCM-related mutation. Pharmacological inhibitors of late Na+ current are promising candidates for an early preventive therapy in young phenotype-negative subjects carrying high-risk HCM-related mutations.

BackgroundThe use of platelet lysate (PL) for the ex-vivo expansion of mesenchymal stromal/stem cells (MSCs) was initially proposed by Doucet et al. in 2005, as an alternative to animal serum. Moreover, regulatory authorities discourage the use of fetal bovine serum (FBS) or other animal derivatives, to avoid risk of zoonoses and xenogeneic immune reactions. Even if many studies investigated PL composition, there still are some open issues related to its use in ex-vivo MSC expansion, especially according to good manufacturing practice (GMP) grade protocols.MethodsAs an authorized cell factory, we report our experience using standardized PL produced by Azienda Ospedaliero Universitaria Meyer Transfusion Service for MSC expansion according to a GMP grade clinical protocol. As suggested by other authors, we performed an in-vitro test on MSCs versus MSCs cultured with FBS that still represents the best way to test PL batches. We compared 12 MSC batches cultured with DMEM 5% PL with similar batches cultured with DMEM 10% FBS, focusing on the MSC proliferation rate, MSC surface marker expression, MSC immunomodulatory and differentiation potential, and finally MSC relative telomere length.ResultsResults confirmed the literature data as PL increases cell proliferation without affecting the MSC immunophenotype, immunomodulatory potential, differentiation potential and relative telomere length.ConclusionsPL can be considered a safe alternative to FBS for ex-vivo expansion of MSC according to a GMP grade protocol. Our experience confirms the literature data: a large number of MSCs for clinical applications can be obtained by expansion with PL, without affecting the MSC main features. Our experience underlines the benefits of a close collaboration between the PL producers (transfusion service) and the end users (cell factory) in a synergy of skills and experiences that can lead to standardized PL production.Electronic supplementary materialThe online version of this article (10.1186/s13287-018-0863-8) contains supplementary material, which is available to authorized users.

In March 1992, a cluster of 89 persons with tuberculosis infection was identified in San Mateo County, California. Thirteen persons (15%), including 11 children, were diagnosed with active pulmonary tuberculosis. All contacts were African Americans who resided in or visited one of two houses used for crack cocaine smoking or dealing. The patient with the index case, a male infected with human immunodeficiency virus, contributed to the transmission of tuberculosis as a transient resident of several dwellings. Public health authorities applied unique intervention methods to control the outbreak, including the use of a mobile health van. Further innovative strategies will be necessary to meet the challenge of this reemerging disease.

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Out-of-hospital cardiac arrest incidence in the different phases of COVID-19 outbreakTo the editor, Last February, Europe was affected by the first wave of the COVID-19 pandemic. Now a second outbreak has begun. Albeit a close relationship between the pandemic trend and the incidence of out-ofhospital cardiac arrest (OHCA) has been documented during the first surge in different countries such as Italy 1,2 the United States 3,4 and France, 5 some elements still remain unclarified.Our aims were (1) to confirm the correlation between the incidence of OHCA and COVID-19 across a longer time period including the downward phase of the pandemic; (2) to compare the incidence of OHCA in the post-and pre-pandemic peak and (3) to verify whether the incidence OHCA correlated more closely with daily COVID-19 diagnoses or with the rate of ICU admissions. We considered all events of OHCA enrolled in the out-of-hospital cardiac arrest register of the Lombardy region (Lombardia CARe; ClinicalTrials.gov Identifier: NCT03197142) from January 1st, 2020 to October 9th, 2020 that have occurred in the provinces of Pavia, Lodi, Cremona, Mantua and Varese (total area 9061 km 2 ; total population of 2,435,939 inhabitants). The daily new cases of COVID-19 in the entire Lombardy region, as well as the daily count of COVID patients admitted in the intensive care units (ICU), were collected from National Department of Civil Protection (http://www.protezionecivile.gov.it/). During the study period, 2488 OHCAs occurred and resuscitation was attempted in 1629 of them (65.5%). The median age was 78 years (IQR 66À86 years); the event occurred at home in 1392 (85.5%); a medical aetiology was found in 1519 (93%); the event was witnessed in 756 (46.4%); the rhythm was non-shockable in 1393 (85.5%) and bystander CPR occurred in 519 (32%). As shown in Fig. 1, the trend of OHCA has followed the trend of the pandemic during both the ascending and the descending phase. A statistically significant correlation was found across the 283 days of observation, reinforcing the deep relationship between the pandemic and OHCA incidence. The

Background The relationship between COVID-19 and out-of-hospital cardiac arrests (OHCAs) has been shown during different phases of the first pandemic wave, but little is known about how to predict where cardiac arrests will increase in case of a third peak. Aim To seek for a correlation between the OHCAs and COVID-19 daily incidence both during the two pandemic waves at a provincial level. Methods We considered all the OHCAs occurred in the provinces of Pavia, Lodi, Cremona, Mantua and Varese, in Lombardy Region (Italy), from 21/02/2020 to 31/12/2020. We divided the study period into period 1, the first 157 days after the outbreak and including the first pandemic wave and period 2, the second 158 days including the second pandemic wave. We calculated the cumulative and daily incidence of OHCA and COVID-19 for the whole territory and for each province for both periods. Results A significant correlation between the daily incidence of COVID-19 and the daily incidence of OHCAs was observed both during the first and the second pandemic period in the whole territory (R = 0.4, p<0.001 for period 1 and 2) and only in those provinces with higher COVID-19 cumulative incidence (period 1: Cremona R = 0.3, p = 0.001; Lodi R = 0.4, p<0.001; Pavia R = 0.3; p = 0.01; period 2: Varese R = 0.4, p<0.001). Conclusions Our results suggest that strictly monitoring the pandemic trend may help in predict which territories will be more likely to experience an OHCAs’ increase. That may also serve as a guide to re-allocate properly health resources in case of further pandemic waves.

Atrial dilation and atrial fibrillation (AF) are common in Hypertrophic CardioMyopathy (HCM) patients and associated with a worsening of prognosis. The pathogenesis of atrial myopathy in HCM remains poorly investigated and no specific association with genotype has been identified. By re-analysis of our cohort of thin-filament HCM patients (Coppini et al. 2014) AF was identified in 10% of patients with sporadic mutations in the cardiac Troponin T gene (TNNT2), while AF occurrence was much higher (25–75%) in patients carrying specific “hot-spot” TNNT2 mutations. To determine the molecular basis of arrhythmia occurrence, two HCM mouse models expressing human TNNT2 variants (a “hot-spot” one, R92Q, and a “sporadic” one, E163R) were selected according to the different pathophysiological pathways previously demonstrated in ventricular tissue. Echocardiography studies showed a significant left atrial dilation in both models, but more pronounced in the R92Q. In E163R atrial trabeculae, in line with what previously observed in ventricular preparations, the energy cost of tension generation was markedly increased. However, no changes of twitch amplitude and kinetics were observed, and there was no atrial arrhythmic propensity. R92Q atrial trabeculae, instead, displayed normal ATP consumption but markedly increased myofilament calcium sensitivity, as previously observed in ventricular preparations. This was associated with reduced inotropic reserve and slower kinetics of twitch contractions and, importantly, with an increased occurrence of spontaneous beats and triggered contractions that represent an intrinsic arrhythmogenic mechanism promoting AF. The association of specific TNNT2 mutations with AF occurrence depends on the mutation-driven pathomechanism (i.e., increased atrial myofilament calcium sensitivity rather than increased myofilament tension cost) and may influence the individual response to treatment.