Translation reprogramming is an evolutionarily conserved driver of phenotypic plasticity and therapeutic resistance in melanoma.

The intratumor microenvironment generates phenotypically distinct but interconvertible malignant cell subpopulations that fuel metastatic spread and therapeutic resistance. Whether different microenvironmental cues impose invasive or therapy-resistant phenotypes via a common mechanism is unknown. In melanoma, low expression of the lineage survival oncogene microphthalmia-associated transcription factor (MITF) correlates with invasion, senescence, and drug resistance. However, how MITF is suppressed in vivo and how MITF-low cells in tumors escape senescence are poorly understood. Here we show that microenvironmental cues, including inflammation-mediated resistance to adoptive T-cell immunotherapy, transcriptionally repress MITF via ATF4 in response to inhibition of translation initiation factor eIF2B. ATF4, a key transcription mediator of the integrated stress response, also activates AXL and suppresses senescence to impose the MITF-low/AXL-high drug-resistant phenotype observed in human tumors. However, unexpectedly, without translation reprogramming an ATF4-high/MITF-low state is insufficient to drive invasion. Importantly, translation reprogramming dramatically enhances tumorigenesis and is linked to a previously unexplained gene expression program associated with anti-PD-1 immunotherapy resistance. Since we show that inhibition of eIF2B also drives neural crest migration and yeast invasiveness, our results suggest that translation reprogramming, an evolutionarily conserved starvation response, has been hijacked by microenvironmental stress signals in melanoma to drive phenotypic plasticity and invasion and determine therapeutic outcome.

Comparing the effects of chemical Ca2+ dyes and R-GECO on contractility and Ca2+ transients in adult and human iPSC cardiomyocytes.

We compared commonly used BAPTA-derived chemical Ca2+ dyes (fura2, Fluo-4, and Rhod-2) with a newer genetically encoded indicator (R-GECO) in single cell models of the heart. We assessed their performance and effects on cardiomyocyte contractility, determining fluorescent signal-to-noise ratios and sarcomere shortening in primary ventricular myocytes from adult mouse and guinea pig, and in human iPSC-derived cardiomyocytes. Chemical Ca2+ dyes displayed dose-dependent contractile impairment in all cell types, and we observed a negative correlation between contraction and fluorescence signal-to-noise ratio, particularly for fura2 and Fluo-4. R-GECO had no effect on sarcomere shortening. BAPTA-based dyes, but not R-GECO, inhibited in vitro acto-myosin ATPase activity. The presence of fura2 accentuated or diminished changes in contractility and Ca2+ handling caused by small molecule modulators of contractility and intracellular ionic homeostasis (mavacamten, levosimendan, and flecainide), but this was not observed when using R-GECO in adult guinea pig left ventricular cardiomyocytes. Ca2+ handling studies are necessary for cardiotoxicity assessments of small molecules intended for clinical use. Caution should be exercised when interpreting small molecule studies assessing contractile effects and Ca2+ transients derived from BAPTA-like chemical Ca2+ dyes in cellular assays, a common platform for cardiac toxicology testing and mechanistic investigation of cardiac disease physiology and treatment.

Measurement of Myofilament-Localized Calcium Dynamics in Adult Cardiomyocytes and the Effect of Hypertrophic Cardiomyopathy Mutations.

RATIONALE: Subcellular Ca2+ indicators have yet to be developed for the myofilament where disease mutation or small molecules may alter contractility through myofilament Ca2+ sensitivity. Here, we develop and characterize genetically encoded Ca2+ indicators restricted to the myofilament to directly visualize Ca2+ changes in the sarcomere. OBJECTIVE: To produce and validate myofilament-restricted Ca2+ imaging probes in an adenoviral transduction adult cardiomyocyte model using drugs that alter myofilament function (MYK-461, omecamtiv mecarbil, and levosimendan) or following cotransduction of 2 established hypertrophic cardiomyopathy disease-causing mutants (cTnT [Troponin T] R92Q and cTnI [Troponin I] R145G) that alter myofilament Ca2+ handling. METHODS AND RESULTS: When expressed in adult ventricular cardiomyocytes RGECO-TnT (Troponin T)/TnI (Troponin I) sensors localize correctly to the sarcomere without contractile impairment. Both sensors report cyclical changes in fluorescence in paced cardiomyocytes with reduced Ca2+ on and increased Ca2+ off rates compared with unconjugated RGECO. RGECO-TnT/TnI revealed changes to localized Ca2+ handling conferred by MYK-461 and levosimendan, including an increase in Ca2+ binding rates with both levosimendan and MYK-461 not detected by an unrestricted protein sensor. Coadenoviral transduction of RGECO-TnT/TnI with hypertrophic cardiomyopathy causing thin filament mutants showed that the mutations increase myofilament [Ca2+] in systole, lengthen time to peak systolic [Ca2+], and delay [Ca2+] release. This contrasts with the effect of the same mutations on cytoplasmic Ca2+, when measured using unrestricted RGECO where changes to peak systolic Ca2+ are inconsistent between the 2 mutations. These data contrast with previous findings using chemical dyes that show no alteration of [Ca2+] transient amplitude or time to peak Ca2+. CONCLUSIONS: RGECO-TnT/TnI are functionally equivalent. They visualize Ca2+ within the myofilament and reveal unrecognized aspects of small molecule and disease-associated mutations in living cells.

Mavacamten rescues increased myofilament calcium sensitivity and dysregulation of Ca2+ flux caused by thin filament hypertrophic cardiomyopathy mutations.

Thin filament hypertrophic cardiomyopathy (HCM) mutations increase myofilament Ca2+ sensitivity and alter Ca2+ handling and buffering. The myosin inhibitor mavacamten reverses the increased contractility caused by HCM thick filament mutations, and we here test its effect on HCM thin filament mutations where the mode of action is not known. Mavacamten (250 nM) partially reversed the increased Ca2+ sensitivity caused by HCM mutations Cardiac troponin T (cTnT) R92Q, and cardiac troponin I (cTnI) R145G in in vitro ATPase assays. The effect of mavacamten was also analyzed in cardiomyocyte models of cTnT R92Q and cTnI R145G containing cytoplasmic and myofilament specific Ca2+ sensors. While mavacamten rescued the hypercontracted basal sarcomere length, the reduced fractional shortening did not improve with mavacamten. Both mutations caused an increase in peak systolic Ca2+ detected at the myofilament, and this was completely rescued by 250 nM mavacamten. Systolic Ca2+ detected by the cytoplasmic sensor was also reduced by mavacamten treatment, although only R145G increased cytoplasmic Ca2+. There was also a reversal of Ca2+ decay time prolongation caused by both mutations at the myofilament but not in the cytoplasm. We thus show that mavacamten reverses some of the Ca2+-sensitive molecular and cellular changes caused by the HCM mutations, particularly altered Ca2+ flux at the myofilament. The reduction of peak systolic Ca2+ as a consequence of mavacamten treatment represents a novel mechanism by which the compound is able to reduce contractility, working synergistically with its direct effect on the myosin motor.NEW & NOTEWORTHY Mavacamten, a myosin inhibitor, is currently in phase-3 clinical trials as a pharmacotherapy for hypertrophic cardiomyopathy (HCM). Its efficacy in HCM caused by mutations in thin filament proteins is not known. We show in reductionist and cellular models that mavacamten can rescue the effects of thin filament mutations on calcium sensitivity and calcium handling although it only partially rescues the contractile cellular phenotype and, in some cases, exacerbates the effect of the mutation.

Considerations for cardiac catheterization laboratory procedures during the COVID-19 pandemic perspectives from the Society for Cardiovascular Angiography and Interventions Emerging Leader Mentorship (SCAI ELM) Members and Graduates.

The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is highly infectious, carries significant morbidity and mortality, and has rapidly resulted in strained health care system and hospital resources. In addition to patient-related care concerns in infected individuals, focus must also relate to diminishing community spread, protection of staff, case selection, and concentration of resources. The current document based on available data and consensus opinion addresses appropriate catheterization laboratory preparedness for treating these patients, including procedure-room readiness to minimize external contamination, safe donning and doffing of personal protective equipment (PPE) to eliminate risk to staff, and staffing algorithms to minimize exposure and maximize team availability. Case selection and management of both emergent and urgent procedures are discussed in detail, including procedures that may be safely deferred or performed bedside.

Hot topics in interventional cardiology: Proceedings from the society for cardiovascular angiography and interventions 2020 think tank.

The society for cardiovascular angiography and interventions (SCAI) think tank is a collaborative venture that brings together interventional cardiologists, administrative partners, and select members of the cardiovascular industry community for high-level field-wide discussions. The 2020 think tank was organized into four parallel sessions reflective of the field of interventional cardiology: (a) coronary intervention, (b) endovascular medicine, (c) structural heart disease, and (d) congenital heart disease (CHD). Each session was moderated by a senior content expert and co-moderated by a member of SCAI's emerging leader mentorship program. This document presents the proceedings to the wider cardiovascular community in order to enhance participation in this discussion, create additional dialogue from a broader base, and thereby aid SCAI and the industry community in developing specific action items to move these areas forward.

Heterogeneity in a large pedigree with Danon disease: Implications for pathogenesis and management.

BACKGROUND: Danon disease is an X-linked disturbance of autophagy manifesting with cognitive impairment and disordered heart and skeletal muscle. After a period of relative stability, patients deteriorate rapidly and may quickly become ineligible for elective heart transplantation - the only life-saving therapy. METHODS: We report a large pedigree with diverse manifestations of Danon disease in hemizygotes and female heterozygotes. RESULTS: Malignant cardiac arrhythmias requiring amiodarone treatment induced thyroid disease in two patients; intractable thyrotoxicosis, which enhances autophagy, caused the death of a 21year-old man. Our patients also had striking elevation of serum troponin I during the accelerated phase of their illness (p<0.01) and rising concentrations heralded cardiac decompensation. We argue for changes to cardiac transplantation eligibility criteria. CONCLUSION: Danon disease causes hypertrophic cardiomyopathy - here we propose a common pathophysiological basis for the metabolic and structural effects of this descriptive class of heart disorders. We also contend that troponin I may have prognostic value and merits exploration for clinical decision-making including health warning bracelets. Rapamycin (Sirolimus®), an approved immunosuppressant which also influences autophagy, may prove beneficial. In the interim, while new treatments are developed, a revaluation of cardiac transplantation eligibility criteria is warranted.

Paravalvular leak closure under intracardiac echocardiographic guidance.

OBJECTIVES: The objective of this study was to determine the safety and efficacy of intracardiac echocardiography (ICE) to guide percutaneous paravalvular leak (PVL) closure. BACKGROUND: PVL following surgical valve replacement occurs in 2%-15% of patients. Percutaneous treatment is an accepted management strategy in patients deemed to be too high risk for redo surgery. This is most commonly performed with transesophageal (TOE) guidance requiring general anesthesia that both potentially further increase the risk of intervention. ICE can be used to guide intervention, facilitating procedures to be performed under local anesthesia without esophageal intubation potentially making procedures shorter and safer and further enabling the treatment of patients that may have been turned down for intervention. METHODS: All patients that underwent ICE-guided percutaneous transcatheter PVL closure between 2006 and 2016 at the John Radcliffe Hospital, Oxford, United Kingdom were retrospectively analyzed. RESULTS: Twenty-one procedures were performed in 18 patients during the study period. Fourteen patients (77.8%) underwent successful ICE guided PVL closure. There were no ICE-related complications. Eleven patients (78.6%) reported symptomatic improvement of at least one New York Heart Association (NYHA) Class and the remaining 3 patients had no change. No patient demonstrated objective evidence of persistent hemolysis following successful closure. There was one death within 30 days of the procedure and 1 year survival was 71.4%. CONCLUSIONS: Percutaneous paravalvular leak closure guided by ICE without the requirement of general anesthesia is feasible, safe, and associated with acceptable procedural success rates.

Percutaneous Device Closure of Paravalvular Leak: Combined Experience From the United Kingdom and Ireland.

BACKGROUND: Paravalvular leak (PVL) occurs in 5% to 17% of patients following surgical valve replacement. Percutaneous device closure represents an alternative to repeat surgery. METHODS: All UK and Ireland centers undertaking percutaneous PVL closure submitted data to the UK PVL Registry. Data were analyzed for association with death and major adverse cardiovascular events (MACE) at follow-up. RESULTS: Three hundred eight PVL closure procedures were attempted in 259 patients in 20 centers (2004-2015). Patient age was 67±13 years; 28% were female. The main indications for closure were heart failure (80%) and hemolysis (16%). Devices were successfully implanted in 91% of patients, via radial (7%), femoral arterial (52%), femoral venous (33%), and apical (7%) approaches. Nineteen percent of patients required repeat procedures. The target valve was mitral (44%), aortic (48%), both (2%), pulmonic (0.4%), or transcatheter aortic valve replacement (5%). Preprocedural leak was severe (61%), moderate (34%), or mild (5.7%) and was multiple in 37%. PVL improved postprocedure (P<0.001) and was none (33.3%), mild (41.4%), moderate (18.6%), or severe (6.7%) at last follow-up. Mean New York Heart Association class improved from 2.7±0.8 preprocedure to 1.6±0.8 (P<0.001) after a median follow-up of 110 (7-452) days. Hospital mortality was 2.9% (elective), 6.8% (in-hospital urgent), and 50% (emergency) (P<0.001). MACE during follow-up included death (16%), valve surgery (6%), late device embolization (0.4%), and new hemolysis requiring transfusion (1.6%). Mitral PVL was associated with higher MACE (hazard ratio [HR], 1.83; P=0.011). Factors independently associated with death were the degree of persisting leak (HR, 2.87; P=0.037), New York Heart Association class (HR, 2.00; P=0.015) at follow-up and baseline creatinine (HR, 8.19; P=0.001). The only factor independently associated with MACE was the degree of persisting leak at follow-up (HR, 3.01; P=0.002). CONCLUSION: Percutaneous closure of PVL is an effective procedure that improves PVL severity and symptoms. Severity of persisting leak at follow-up is independently associated with both MACE and death. Percutaneous closure should be considered as an alternative to repeat surgery.

Human-based approaches to pharmacology and cardiology: an interdisciplinary and intersectorial workshop.

Both biomedical research and clinical practice rely on complex datasets for the physiological and genetic characterization of human hearts in health and disease. Given the complexity and variety of approaches and recordings, there is now growing recognition of the need to embed computational methods in cardiovascular medicine and science for analysis, integration and prediction. This paper describes a Workshop on Computational Cardiovascular Science that created an international, interdisciplinary and inter-sectorial forum to define the next steps for a human-based approach to disease supported by computational methodologies. The main ideas highlighted were (i) a shift towards human-based methodologies, spurred by advances in new in silico, in vivo, in vitro, and ex vivo techniques and the increasing acknowledgement of the limitations of animal models. (ii) Computational approaches complement, expand, bridge, and integrate in vitro, in vivo, and ex vivo experimental and clinical data and methods, and as such they are an integral part of human-based methodologies in pharmacology and medicine. (iii) The effective implementation of multi- and interdisciplinary approaches, teams, and training combining and integrating computational methods with experimental and clinical approaches across academia, industry, and healthcare settings is a priority. (iv) The human-based cross-disciplinary approach requires experts in specific methodologies and domains, who also have the capacity to communicate and collaborate across disciplines and cross-sector environments. (v) This new translational domain for human-based cardiology and pharmacology requires new partnerships supported financially and institutionally across sectors. Institutional, organizational, and social barriers must be identified, understood and overcome in each specific setting.

Initial use of the new GORE(®) septal occluder in patent foramen ovale closure: implantation and preliminary results.

BACKGROUND: A number of devices are available for percutaneous closure of a clinically significant patent foramen ovale (PFO). The new GORE(®) septal occluder (GSO) is a nonself-centering device consisting of an expanded polytetrafluoroethylene tube supported by a frame of nitinol wire conforming into a double disk. This study reports the first clinical GSO implantation experience. METHODS: GSO implantation in 20 consecutive patients is reported. Inclusion criteria were all patients referred with a significant PFO implicated in paradoxical embolism or transient right to left shunting causing desaturation. Procedures were performed under local anaesthesia and intracardiac echocardiography (ICE) in addition to fluoroscopy. Procedural data, acute and early closure rates were examined. RESULTS: All patients underwent successful day-case device implantation. Eleven patients had previous stroke, five had transient ischemic attacks, two had a history suspicious of PFO-related desaturation, and two had a history suspicious of PFO-related peripheral thromboembolism. Acute closure rates on IVC injection bubble testing were 100% at implant and 100% (14/14) at 1 month. Average PFO balloon size was 8.0 ± 3.6(range 2.0-16.7) mm, mean fluoroscopic implantation time 3.0 ± 1.7(range 0.7-6.3) min, radiation dose 283 ± 340 (range 6-1,431) µGym(2), and total procedural time 34.8 ± 8.0 (range 22-53) min. 5 × 20 mm(2), 7 × 25 m(2), 8 × 30 mm(2) GSO devices were implanted, aiming for device size at least twice balloon PFO size. Cases included aneurysmal septums with up to 30 mm deviation and tunnels up to 12 mm long. Removal and repositioning of two devices was performed on two occasions after uncertainty about device locking. At 1 month follow-up, two patients had brief self-terminating episodes of suspected atrial fibrillation, all had normal resting ECGs. No thromboembolic/neurological events were reported. CONCLUSIONS: The GSO can be implanted under local anaesthesia and ICE with low procedural and fluoroscopy times with high procedural success as a day case. No residual shunts were seen. This initial experience suggests that it is a safe and effective device for PFO closure.

The Future of LAAC-In 5, 10, and 20 Years.

Early experience with percutaneous LAA closure documented complication rates of ∼10%, with failure to implant devices in ∼10% of patients. These numbers are unrecognizable in contemporary practice due to the iterative changes made largely in the last 10 years. Here we look forward to ask what might change, and when, to bring percutaneous LAA closure out of the niche early adopter centers into routine use. We consider the opportunity to incorporate different technologies into LAAc devices in the context of managing patient with atrial fibrillation. Finally, we consider how to make the procedure safer and more effective.

The Future of LAAC-In 5, 10, and 20 Years.

Early experience with percutaneous LAA closure documented complication rates of ∼10%, with failure to implant devices in ∼10% of patients. These numbers are unrecognizable in contemporary practice due to the iterative changes made largely in the last 10 years. Here we look forward to ask what might change, and when, to bring percutaneous LAA closure out of the niche early adopter centers into routine use. We consider the opportunity to incorporate different technologies into LAAc devices in the context of managing patient with atrial fibrillation. Finally, we consider how to make the procedure safer and more effective.

High-Throughput Optical Controlling and Recording Calcium Signal in iPSC-Derived Cardiomyocytes for Toxicity Testing and Phenotypic Drug Screening.

Understanding how excitable cells work in health and disease and how that behavior can be altered by small molecules or genetic manipulation is important. Genetically encoded calcium indicators (GECIs) with multiple emission windows can be combined (e.g., for simultaneous observation of distinct subcellular events) or used in extended applications with other light-dependent actuators in excitable cells (e.g., combining genetically encoded optogenetic control with spectrally compatible calcium indicators). Such approaches have been used in primary or stem cell-derived neurons, cardiomyocytes, and pancreatic beta-cells. However, it has been challenging to increase the throughput, or duration of observation, of such approaches due to limitations of the instruments, analysis software, indicator performance, and gene delivery efficiency. Here, a high-performance green GECI, mNeonGreen-GECO (mNG-GECO), and red-shifted GECI, K-GECO, is combined with optogenetic control to achieve all-optical control and visualization of cellular activity in a high-throughput imaging format using a High-Content Imaging System. Applications demonstrating cardiotoxicity testing and phenotypic drug screening with healthy and patient-derived iPSC-CMs are shown. In addition, multi-parametric assessments using combinations of spectral and calcium affinity indicator variants (NIR-GECO, LAR-GECO, and mtGCEPIA or Orai1-G-GECO) are restricted to different cellular compartments are also demonstrated in the iPSC-CM model.

Sustainable Resumption of Cardiac Catheterization Laboratory Procedures, and the Importance of Testing, During Endemic COVID-19.

PURPOSE: As second and third waves of the COVID-19 pandemic challenge healthcare in North America and Europe once again, we analyze the impact of the first wave on routine elective cardiovascular care, and the differential COVID risk emerging within our patient groups and staff. PERSPECTIVE: We describe the need to sustainably resume, and temporarily expand, routine elective cardiac services in the face of resurgent COVID-19. Some, but not all, cardiac patient groups are particularly vulnerable to adverse outcomes following COVID-19 infection. We explore mitigation measures at the institutional level to increase resilience within cardiac services to enable them to operate deep into subsequent waves of COVID infection which place unprecedented demands on intensive care infrastructure. As measures to eradicate the virus appear to have failed in many countries, and vaccine roll-out will take many months we take the view that the threat imposed by endemic COVID-19 alters the way elective procedural care should be offered to cardiovascular patients. CONCLUSION: Our patients are at definite risk from their cardiovascular disease, and a return to suspension of proven prognostic interventional treatments on an elective basis - the default for the first wave - must be avoided at all costs.

An assessment of annual procedure volumes and therapy adoption of transcatheter closure of patent foramen ovale in four European countries.

INTRODUCTION: Patent foramen ovale closure reduces recurrence of cryptogenic ischaemic stroke compared to anti-platelet therapy. Our goal was to determine procedure volumes and closure utilisation as a proportion of candidates in four large European countries. PATIENTS AND METHODS: National statistics were obtained for Germany, England, France, and Italy for the last available five years (2014-2018). Eligibility was aligned to the enrolment criteria of pivotal trials and current consensus documents. Stroke and transient ischaemic attack incidences were obtained from epidemiological registries and claims data. The eligible candidate pool for analysis included current year candidates plus untreated patients from the prior two years. Absolute strokes avoided assumed the hazard ratio for ischaemic stroke recurrence from a recent meta-analysis. RESULTS: In 2018, closure incidence rates were 5.64, 0.53, 2.94 and 5.26 per 100,000 in Germany, England, France and Italy, respectively. This reflects five-year increases of 128% in Germany, 462% in France and 36% in Italy (p < 0.05 for all), and a decline of 37% in England. The proportions of treated patients versus candidates for the combined stroke and transient ischaemic attack pool were 55%, 30%, 80%, and 6%, respectively. DISCUSSION: Patent foramen ovale closure volumes increased after the 2017 announcement of positive trial results but still differ substantially across large European countries. If all closure candidates in 2018 with prior ischaemic stroke were treated, the resulting absolute reduction of recurrent ischaemic strokes, compared to anti-platelet therapy alone, would be between 782 and 2295 across the four countries over five years. CONCLUSION: Many eligible patients at risk for a recurrent cryptogenic event might remain untreated due to regional practice variations.

Outcomes of Percutaneous and Surgical Pulmonary Valve Implantation.

BACKGROUND: The objective of this study is to describe the recent trends and in-hospital outcomes with percutaneous pulmonic valve implantation (PPVI) and surgical pulmonic valve replacement (SPVR) in adult hospitals in the US after the availability of both the Melody valve (Medtronic Inc., Minneapolis, Minnesota) and the Sapien XT valve (Edwards Lifesciences, Irvine, CA). METHODS: We queried the National Inpatient Sample database (NIS) from January 2016 to December 2017 to identify hospitalizations for PPVI and SPVR. RESULTS: We identified 5455 weighted discharges with PPVI and SPVR (PPVI=1140, SPVR=4305). PPVI procedures had increased in number over 2016 and 2017 (115 procedure at the first quarter of 2016, 195 procedures in the final quarter of 2017, P-trend=0.086), while SPVR volume remained constant. The incidence of in-hospital mortality was low with both procedures (SPRV: 1.6% vs. PPVI: 0.9%, p=0.071). SPVR had worse in-hospital outcomes, was associated with a longer length of stay [5 days vs. 1 day, p<0.001], and comparable cost of index hospitalization [$51,657 vs. $51,193] compared with PPVI. CONCLUSION: After approval of the Sapien valve for commercial use in 2016, PPVI procedures have increased in frequency. PPVI is associated with lower procedural complications than SPVR, however, both carry a low risk of mortality. Despite the higher cost of the valves and delivery systems, PPVI is associated with a slightly lower cost of index hospitalization compared with SPVR, likely due to the higher in-hospital complications and LOS of the latter.