Role of arrhythmic phenotype in prognostic stratification and management of dilated cardiomyopathy.

AIMS: Dilated cardiomyopathy (DCM) with arrhythmic phenotype combines phenotypical aspects of DCM and predisposition to ventricular arrhythmias, typical of arrhythmogenic cardiomyopathy. The definition of DCM with arrhythmic phenotype is not universally accepted, leading to uncertainty in the identification of high-risk patients. This study aimed to assess the prognostic impact of arrhythmic phenotype in risk stratification and the correlation of arrhythmic markers with high-risk arrhythmogenic gene variants in DCM patients. METHODS AND RESULTS: In this multicentre study, DCM patients with available genetic testing were analysed. The following arrhythmic markers, present at baseline or within 1 year of enrolment, were tested: unexplained syncope, rapid non-sustained ventricular tachycardia (NSVT), ≥1000 premature ventricular contractions/24 h or ≥50 ventricular couplets/24 h. LMNA, FLNC, RBM20, and desmosomal pathogenic or likely pathogenic gene variants were considered high-risk arrhythmogenic genes. The study endpoint was a composite of sudden cardiac death and major ventricular arrhythmias (SCD/MVA). We studied 742 DCM patients (45 ± 14 years, 34% female, 410 [55%] with left ventricular ejection fraction [LVEF] <35%). During a median follow-up of 6 years (interquartile range 1.6-12.1), unexplained syncope and NSVT were the only arrhythmic markers associated with SCD/MVA, and the combination of the two markers carried a significant additive risk of SCD/MVA, incremental to LVEF and New York Heart Association class. The probability of identifying an arrhythmogenic genotype rose from 8% to 30% if both early syncope and NSVT were present. CONCLUSION: In DCM patients, the combination of early detected NSVT and unexplained syncope increases the risk of life-threatening arrhythmic outcomes and can aid the identification of carriers of malignant arrhythmogenic genotypes.

Apoptosis, a useful marker in the management of hot-phase cardiomyopathy?

AIMS: 'Hot phases', characterized by chest pain and troponin release, may represent the first clinical presentation of arrhythmogenic cardiomyopathies. Differential diagnosis with acute myocarditis is an unmet challenge for the clinicians. We sought to investigate histological and genetic features in patients with cardiomyopathy presenting with hot phases. METHODS AND RESULTS: We evaluated a case series of consecutive patients hospitalized for suspected 'hot-phase cardiomyopathy' in two Italian centres from June 2017 to March 2022 (median follow-up 18 months) that underwent both endomyocardial biopsy (EMB) and genetic testing. Apoptosis was confirmed with TUNEL assay. Among the 17 enrolled patients (mean age 34 ± 15 years, 76% male), only six patients (35%) presented standard histological and immunohistochemical markers for significant cardiac inflammation at EMB. Conversely, apoptosis was found in 13 patients (77%). Genetic testing was positive for a pathogenic/likely pathogenic (P/LP) variant in genes involved in cardiomyopathies (most frequently in DSP) in eight patients (48%), rising to 62% among patients with apoptosis on EMB. Notably, all patients without apoptosis tested negative for P/LP disease-related variants. Left ventricular ejection fraction was lower in patients showing apoptosis at EMB compared to those without (p = 0.003). CONCLUSIONS: Apoptosis, rather than significant inflammation, was mostly prevalent in this case series of patients with 'hot-phase' presentation, especially in carriers of variants in cardiomyopathy-related genes. Detecting apoptosis on EMB might guide clinicians in performing genetic testing and in more tailored therapeutic choices in 'hot-phase cardiomyopathy'.

Risks of Ventricular Arrhythmia and Heart Failure in Carriers of RBM20 Variants.

BACKGROUND: Variants in RBM20 are reported in 2% to 6% of familial cases of dilated cardiomyopathy and may be associated with fatal ventricular arrhythmia and rapid heart failure progression. We sought to determine the risk of adverse events in RBM20 variant carriers and the impact of sex on outcomes. METHODS: Consecutive probands and relatives carrying RBM20 variants were retrospectively recruited from 12 cardiomyopathy units. The primary end point was a composite of malignant ventricular arrhythmia (MVA) and end-stage heart failure (ESHF). MVA and ESHF end points were also analyzed separately and men and women compared. Left ventricular ejection fraction (LVEF) contemporary to MVA was examined. RBM20 variant carriers with left ventricular systolic dysfunction (RBM20LVSD) were compared with variant-elusive patients with idiopathic left ventricular systolic dysfunction. RESULTS: Longitudinal follow-up data were available for 143 RBM20 variant carriers (71 men; median age, 35.5 years); 7 of 143 had an MVA event at baseline. Thirty of 136 without baseline MVA (22.0%) reached the primary end point, and 16 of 136 (11.8%) had new MVA with no significant difference between men and women (log-rank P=0.07 and P=0.98, respectively). Twenty of 143 (14.0%) developed ESHF (17 men and 3 women; log-rank P<0.001). Four of 10 variant carriers with available LVEF contemporary to MVA had an LVEF >35%. At 5 years, 15 of 67 (22.4%) RBM20LVSD versus 7 of 197 (3.6%) patients with idiopathic left ventricular systolic dysfunction had reached the primary end point (log-rank P<0.001). RBM20 variant carriage conferred a 6.0-fold increase in risk of the primary end point. CONCLUSIONS: RBM20 variants are associated with a high risk of MVA and ESHF compared with idiopathic left ventricular systolic dysfunction. The risk of MVA in male and female RBM20 variant carriers is similar, but male sex is strongly associated with ESHF.

Cardiology of the future: xenotransplantation with porcine heart.

The reduced availability of human donor hearts compared with the needs of patients with advanced heart failure refractory to medical therapy has promoted the search for therapeutic alternatives to cardiac allografts. Porcine heart xenotransplantation represents one of the most promising frontiers in this field today. From the first researches in the 1960s to today, the numerous advances achieved in the field of surgical techniques, genetic engineering and immunosuppression have made it possible at the beginning of 2022 to carry out the first swine-to-human heart transplant, attaining a survival of 2 months after surgery. The main intellectual and experimental stages that have marked the history of xenotransplantation, the latest acquisitions in terms of genetic editing, as well as the improvement of immunosuppressive therapy are discussed analytically in this article in order to illustrate the underlying complexity of this therapeutic model.

Evolving trends in epidemiology and natural history of cardiac amyloidosis: 30-year experience from a tertiary referral center for cardiomyopathies.

Objective: Natural history of cardiac amyloidosis (CA) is poorly understood. We aimed to examine the changing mortality of different types of CA over a 30-year period. Patients and methods: Consecutive patients included in the "Trieste CA Registry" from January 1, 1990 through December 31, 2021 were divided into a historical cohort (diagnosed before 2016) and a contemporary cohort (diagnosed after 2016). Light chain (AL), transthyretin (ATTR) and other forms of CA were defined according to international recommendations. The primary and secondary outcome measures were all-cause mortality and cardiac death, respectively. Results: We enrolled 182 patients: 47.3% AL-CA, 44.5% ATTR-CA, 8.2% other etiologies. The number of patients diagnosed with AL and ATTR-CA progressively increased over time, mostly ATTR-CA patients (from 21% before 2016 to 67% after 2016) diagnosed non-invasively. The more consistent increase in event-rate was observed in the long-term (after 50 months) in ATTR-CA compared to the early increase in mortality in AL-CA. In the contemporary cohort, during a median follow up of 16 [4-30] months, ATTR-CA was associated with improved overall and cardiac survival compared to AL-CA. At multivariable analysis, ATTR-CA (HR 0.42, p = 0.03), eGFR (HR 0.98, p = 0.033) and ACE-inhibitor therapy (HR 0.24, p < 0.001) predicted overall survival in the contemporary cohort. Conclusion: Incidence and prevalence rates of ATTR-CA and, to a less extent, of AL-CA have been increasing over time, with significant improvements in 2-year survival of ATTR-CA patients from the contemporary cohort. Reaching an early diagnosis and starting disease-modifying treatments will improve long-term survival in CA.

Cardioprotective factors against myocardial infarction selected in vivo from an AAV secretome library.

Therapies for patients with myocardial infarction and heart failure are urgently needed, in light of the breadth of these conditions and lack of curative treatments. To systematically identify previously unidentified cardioactive biologicals in an unbiased manner in vivo, we developed cardiac FunSel, a method for the systematic, functional selection of effective factors using a library of 1198 barcoded adeno-associated virus (AAV) vectors encoding for the mouse secretome. By pooled vector injection into the heart, this library was screened to functionally select for factors that confer cardioprotection against myocardial infarction. After two rounds of iterative selection in mice, cardiac FunSel identified three proteins [chordin-like 1 (Chrdl1), family with sequence similarity 3 member C (Fam3c), and Fam3b] that preserve cardiomyocyte viability, sustain cardiac function, and prevent pathological remodeling. In particular, Chrdl1 exerted its protective activity by binding and inhibiting extracellular bone morphogenetic protein 4 (BMP4), which resulted in protection against cardiomyocyte death and induction of autophagy in cardiomyocytes after myocardial infarction. Chrdl1 also inhibited fibrosis and maladaptive cardiac remodeling by binding transforming growth factor-ß (TGF-ß) and preventing cardiac fibroblast differentiation into myofibroblasts. Production of secreted and circulating Chrdl1, Fam3c, and Fam3b from the liver also protected the heart from myocardial infarction, thus supporting the use of the three proteins as recombinant factors. Together, these findings disclose a powerful method for the in vivo, unbiased selection of tissue-protective factors and describe potential cardiac therapeutics.

Importance of genotype for risk stratification in arrhythmogenic right ventricular cardiomyopathy using the 2019 ARVC risk calculator.

AIMS: To study the impact of genotype on the performance of the 2019 risk model for arrhythmogenic right ventricular cardiomyopathy (ARVC). METHODS AND RESULTS: The study cohort comprised 554 patients with a definite diagnosis of ARVC and no history of sustained ventricular arrhythmia (VA). During a median follow-up of 6.0 (3.1,12.5) years, 100 patients (18%) experienced the primary VA outcome (sustained ventricular tachycardia, appropriate implantable cardioverter defibrillator intervention, aborted sudden cardiac arrest, or sudden cardiac death) corresponding to an annual event rate of 2.6% [95% confidence interval (CI) 1.9-3.3]. Risk estimates for VA using the 2019 ARVC risk model showed reasonable discriminative ability but with overestimation of risk. The ARVC risk model was compared in four gene groups: PKP2 (n = 118, 21%); desmoplakin (DSP) (n = 79, 14%); other desmosomal (n = 59, 11%); and gene elusive (n = 160, 29%). Discrimination and calibration were highest for PKP2 and lowest for the gene-elusive group. Univariable analyses revealed the variable performance of individual clinical risk markers in the different gene groups, e.g. right ventricular dimensions and systolic function are significant risk markers in PKP2 but not in DSP patients and the opposite is true for left ventricular systolic function. CONCLUSION: The 2019 ARVC risk model performs reasonably well in gene-positive ARVC (particularly for PKP2) but is more limited in gene-elusive patients. Genotype should be included in future risk models for ARVC.

Phenotypic Expression, Natural History, and Risk Stratification of Cardiomyopathy Caused by Filamin C Truncating Variants.

BACKGROUND: Filamin C truncating variants (FLNCtv) cause a form of arrhythmogenic cardiomyopathy: the mode of presentation, natural history, and risk stratification of FLNCtv remain incompletely explored. We aimed to develop a risk profile for refractory heart failure and life-threatening arrhythmias in a multicenter cohort of FLNCtv carriers. METHODS: FLNCtv carriers were identified from 10 tertiary care centers for genetic cardiomyopathies. Clinical and outcome data were compiled. Composite outcomes were all-cause mortality/heart transplantation/left ventricle assist device (D/HT/LVAD), nonarrhythmic death/HT/LVAD, and sudden cardiac death/major ventricular arrhythmias. Previously established cohorts of 46 patients with LMNA and 60 with DSP-related arrhythmogenic cardiomyopathies were used for prognostic comparison. RESULTS: Eighty-five patients carrying FLNCtv were included (42±15 years, 53% men, 45% probands). Phenotypes were heterogeneous at presentation: 49% dilated cardiomyopathy, 25% arrhythmogenic left dominant cardiomyopathy, 3% arrhythmogenic right ventricular cardiomyopathy. Left ventricular ejection fraction was <50% in 64% of carriers and 34% had right ventricular fractional area changes (RVFAC=(right ventricular end-diastolic area - right ventricular end-systolic area)/right ventricular end-diastolic area) <35%. During follow-up (median time 61 months), 19 (22%) carriers experienced D/HT/LVAD, 13 (15%) experienced nonarrhythmic death/HT/LVAD, and 23 (27%) experienced sudden cardiac death/major ventricular arrhythmias. The sudden cardiac death/major ventricular arrhythmias incidence of FLNCtv carriers did not significantly differ from LMNA carriers and DSP carriers. In FLNCtv carriers, left ventricular ejection fraction was associated with the risk of D/HT/LVAD and nonarrhythmic death/HT/LVAD. CONCLUSIONS: Among patients referred to tertiary referral centers, FLNCtv arrhythmogenic cardiomyopathy is phenotypically heterogeneous and characterized by a high risk of life-threatening arrhythmias, which does not seem to be associated with the severity of left ventricular dysfunction.

[Diagnostic work-up and clinical management of cardiomyopathies: the operative protocol from the Cardiothoracovascular Department of Trieste, Italy]. / Inquadramento e gestione delle cardiomiopatie: il protocollo della Cardiologia di Trieste.

Cardiomyopathies are primary myocardial disorders, genetically determined, with clinical onset between the third and the fifth decade of life. They represent the main causes of sudden cardiac death and heart failure in the youth. The more common myocardial diseases in clinical practice are dilated cardiomyopathy, arrhythmogenic cardiomyopathy and hypertrophic cardiomyopathy. Next generation sequencing techniques, recently available for genetics researches, together with the diffusion of advanced imaging techniques, permitted in the last years a deeper knowledge of these pathologies. Nevertheless, diagnosis, etiology and several aspects of patients' clinical management remain complex and controversial. This review paper aims to propose some operative flow-charts, derived from scientific evidences and the internal protocol of the Cardiothoracovascular Department of Trieste Hospital, Italian referral Center for cardiomyopathies and heart failure, with more than 30 years of experience in diagnosis and management of patients who suffer from primary myocardial disorders.

Preserved Skeletal Muscle Mitochondrial Function, Redox State, Inflammation and Mass in Obese Mice with Chronic Heart Failure.

Background: Skeletal muscle (SM) mitochondrial dysfunction, oxidative stress, inflammation and muscle mass loss may worsen prognosis in chronic heart failure (CHF). Diet-induced obesity may also cause SM mitochondrial dysfunction as well as oxidative stress and inflammation, but obesity per se may be paradoxically associated with high SM mass and mitochondrial adenosine triphosphate (ATP) production, as well as with enhanced survival in CHF. Methods: We investigated interactions between myocardial infarction(MI)-induced CHF and diet-induced obesity (12-wk 60% vs. standard 10% fat) in modulating gastrocnemius muscle (GM) mitochondrial ATP and tissue superoxide generation, oxidized glutathione (GSSG), cytokines and insulin signalling activation in 10-wk-old mice in the following groups: lean sham-operated, lean CHF (LCHF), obese CHF (ObCHF; all n = 8). The metabolic impact of obesity per se was investigated by pair-feeding ObCHF to standard diet with stabilized excess body weight until sacrifice at wk 8 post-MI. Results: Compared to sham, LCHF had low GM mass, paralleled by low mitochondrial ATP production and high mitochondrial reative oxygen species (ROS) production, pro-oxidative redox state, pro-inflammatory cytokine changes and low insulin signaling (p < 0.05). In contrast, excess body weight in pair-fed ObCHF was associated with high GM mass, preserved mitochondrial ATP and mitochondrial ROS production, unaltered redox state, tissue cytokines and insulin signaling (p = non significant vs. Sham, p < 0.05 vs. LCHF) despite higher superoxide generation from non-mitochondrial sources. Conclusions: CHF disrupts skeletal muscle mitochondrial function in lean rodents with low ATP and high mitochondrial ROS production, associated with tissue pro-inflammatory cytokine profile, low insulin signaling and muscle mass loss. Following CHF onset, obesity per se is associated with high skeletal muscle mass and preserved tissue ATP production, mitochondrial ROS production, redox state, cytokines and insulin signaling. These paradoxical and potentially favorable obesity-associated metabolic patterns could contribute to reported obesity-induced survival advantage in CHF.

Clinical Phenotypes and Prognosis of Dilated Cardiomyopathy Caused by Truncating Variants in the TTN Gene.

BACKGROUND: Truncating variants in the TTN gene (TTNtv) are the commonest cause of heritable dilated cardiomyopathy. This study aimed to study the phenotypes and outcomes of TTNtv carriers. METHODS: Five hundred thirty-seven individuals (61% men; 317 probands) with TTNtv were recruited in 14 centers (372 [69%] with baseline left ventricular systolic dysfunction [LVSD]). Baseline and longitudinal clinical data were obtained. The primary end point was a composite of malignant ventricular arrhythmia and end-stage heart failure. The secondary end point was left ventricular reverse remodeling (left ventricular ejection fraction increase by ≥10% or normalization to ≥50%). RESULTS: Median follow-up was 49 (18-105) months. Men developed LVSD more frequently and earlier than women (45±14 versus 49±16 years, respectively; P=0.04). By final evaluation, 31%, 45%, and 56% had atrial fibrillation, frequent ventricular ectopy, and nonsustained ventricular tachycardia, respectively. Seventy-six (14.2%) individuals reached the primary end point (52 [68%] end-stage heart failure events, 24 [32%] malignant ventricular arrhythmia events). Malignant ventricular arrhythmia end points most commonly occurred in patients with severe LVSD. Male sex (hazard ratio, 1.89 [95% CI, 1.04-3.44]; P=0.04) and left ventricular ejection fraction (per 10% decrement from left ventricular ejection fraction, 50%; hazard ratio, 1.63 [95% CI, 1.30-2.04]; P<0.001) were independent predictors of the primary end point. Two hundred seven of 300 (69%) patients with LVSD had evidence of left ventricular reverse remodeling. In a subgroup of 29 of 74 (39%) patients with initial left ventricular reverse remodeling, there was a subsequent left ventricular ejection fraction decrement. TTNtv location was not associated with statistically significant differences in baseline clinical characteristics, left ventricular reverse remodeling, or outcomes on multivariable analysis (P=0.07). CONCLUSIONS: TTNtv is characterized by frequent arrhythmia, but malignant ventricular arrhythmias are most commonly associated with severe LVSD. Male sex and LVSD are independent predictors of outcomes. Mutation location does not impact clinical phenotype or outcomes.

Risk of sudden cardiac death in New York Heart Association class I patients with dilated cardiomyopathy: A competing risk analysis.

AIMS: Primary prevention implantable cardioverter defibrillator (ICD) is not generally recommended in New York Heart Association (NYHA) I class patients with dilated cardiomyopathy (DCM). This study sought to assess the competing risk of sudden cardiac death (SCD) in DCM patients with left ventricular ejection fraction (EF) ≤35% and NYHA I class. METHODS: A total of 272 DCM patients with EF ≤35% and NYHA class I-III after ≥3 months of guideline-directed medical therapy were included. The risk of SCD and SCD/malignant ventricular arrhythmias (MVA) was assessed in NYHA I vs. NYHA II and NYHA III groups by competing risk analysis. RESULTS: NYHA I patients were younger, had higher EF and smaller left atrium, were less likely receiving mineral corticoid receptor antagonists. The cumulative incidence of SCD (p = 0.92) and SCD/MVA (p = 0.42) did not differ between NYHA I vs NYHA II-III classes. NYHA class did not influence the association between ICD and SCD risk (p for interaction = 0.125). CONCLUSIONS: In this cohort of DCMs, patients with EF ≤35% and NYHA I class were exposed to a risk of SCD and life-threatening arrhythmias not different from NYHA II-III. Therefore, inclusion of asymptomatic patients with DCM and systolic dysfunction should be strongly considered in future randomized studies on primary prevention ICD.

The K219T-Lamin mutation induces conduction defects through epigenetic inhibition of SCN5A in human cardiac laminopathy.

Mutations in LMNA, which encodes the nuclear proteins Lamin A/C, can cause cardiomyopathy and conduction disorders. Here, we employ induced pluripotent stem cells (iPSCs) generated from human cells carrying heterozygous K219T mutation on LMNA to develop a disease model. Cardiomyocytes differentiated from these iPSCs, and which thus carry K219T-LMNA, have altered action potential, reduced peak sodium current and diminished conduction velocity. Moreover, they have significantly downregulated Nav1.5 channel expression and increased binding of Lamin A/C to the promoter of SCN5A, the channel's gene. Coherently, binding of the Polycomb Repressive Complex 2 (PRC2) protein SUZ12 and deposition of the repressive histone mark H3K27me3 are increased at SCN5A. CRISPR/Cas9-mediated correction of the mutation re-establishes sodium current density and SCN5A expression. Thus, K219T-LMNA cooperates with PRC2 in downregulating SCN5A, leading to decreased sodium current density and slower conduction velocity. This mechanism may underlie the conduction abnormalities associated with LMNA-cardiomyopathy.

In Vivo Functional Selection Identifies Cardiotrophin-1 as a Cardiac Engraftment Factor for Mesenchymal Stromal Cells.

BACKGROUND: Transplantation of cells into the infarcted heart has significant potential to improve myocardial recovery; however, low efficacy of cell engraftment still limits therapeutic benefit. Here, we describe a method for the unbiased, in vivo selection of cytokines that improve mesenchymal stromal cell engraftment into the heart both in normal conditions and after myocardial infarction. METHODS: An arrayed library of 80 secreted factors, including most of the currently known interleukins and chemokines, were individually cloned into adeno-associated viral vectors. Pools from this library were then used for the batch transduction of bone marrow-derived mesenchymal stromal cells ex vivo, followed by intramyocardial cell administration in normal and infarcted mice. Three weeks after injection, vector genomes were recovered from the few persisting cells and identified by sequencing DNA barcodes uniquely labeling each of the tested cytokines. RESULTS: The most effective molecule identified by this competitive engraftment screening was cardiotrophin-1, a member of the interleukin-6 family. Intracardiac injection of mesenchymal stromal cells transiently preconditioned with cardiotrophin-1 preserved cardiac function and reduced infarct size, parallel to the persistence of the transplanted cells in the healing hearts for at least 2 months after injection. Engraftment of cardiotrophin-1-treated mesenchymal stromal cells was consequent to signal transducer and activator of transcription 3-mediated activation of the focal adhesion kinase and its associated focal adhesion complex and the consequent acquisition of adhesive properties by the cells. CONCLUSIONS: These results support the feasibility of selecting molecules in vivo for their functional properties with adeno-associated viral vector libraries and identify cardiotrophin-1 as a powerful cytokine promoting cell engraftment and thus improving cell therapy of the infarcted myocardium.

MiR-320a as a Potential Novel Circulating Biomarker of Arrhythmogenic CardioMyopathy.

Diagnosis of Arrhythmogenic CardioMyopathy (ACM) is challenging and often late after disease onset. No circulating biomarkers are available to date. Given their involvement in several cardiovascular diseases, plasma microRNAs warranted investigation as potential non-invasive diagnostic tools in ACM. We sought to identify circulating microRNAs differentially expressed in ACM with respect to Healthy Controls (HC) and Idiopathic Ventricular Tachycardia patients (IVT), often in differential diagnosis. ACM and HC subjects were screened for plasmatic expression of 377 microRNAs and validation was performed in 36 ACM, 53 HC, 21 IVT. Variable importance in data partition was estimated through Random Forest analysis and accuracy by Receiver Operating Curves. Plasmatic miR-320a showed 0.53 ± 0.04 fold expression difference in ACM vs. HC (p < 0.01). A similar trend was observed when comparing ACM (n = 13) and HC (n = 17) with athletic lifestyle, a ACM precipitating factor. Importantly, ACM patients miR-320a showed 0.78 ± 0.05 fold expression change vs. IVT (p = 0.03). When compared to non-invasive ACM diagnostic parameters, miR-320a ranked highly in discriminating ACM vs. IVT and it increased their accuracy. Finally, miR-320a expression did not correlate with ACM severity. Our data suggest that miR-320a may be considered a novel potential biomarker of ACM, specifically useful in ACM vs. IVT differentiation.

AAV-mediated in vivo functional selection of tissue-protective factors against ischaemia.

Functional screening of expression libraries in vivo would offer the possibility of identifying novel biotherapeutics without a priori knowledge of their biochemical function. Here we describe a procedure for the functional selection of tissue-protective factors based on the in vivo delivery of arrayed cDNA libraries from the mouse secretome using adeno-associated virus (AAV) vectors. Application of this technique, which we call FunSel, in the context of acute ischaemia, revealed that the peptide ghrelin protects skeletal muscle and heart from ischaemic damage. When delivered to the heart using an AAV9 vector, ghrelin markedly reduces infarct size and preserves cardiac function over time. This protective activity associates with the capacity of ghrelin to sustain autophagy and remove dysfunctional mitochondria after myocardial infarction. Our findings describe an innovative tool to identify biological therapeutics and reveal a novel role of ghrelin as an inducer of myoprotective autophagy.