Hajjar, Roger J.

Abstract Aims This study aims to explore long-term clinical outcomes of cardiopoiesis-guided stem cell therapy for ischaemic heart failure assessed in the Congestive Heart Failure Cardiopoietic Regenerative Therapy (CHART-1) trial. Methods and results CHART-1 is a multinational, randomized, and double-blind trial conducted in 39 centres in heart failure patients (n = 315) on standard-of-care therapy. The ‘active’ group received cardiopoietic stem cells delivered intramyocardially using a retention-enhanced catheter. The ‘control’ group underwent patient-level sham procedure. Patients were followed up to 104 weeks. In the entire study population, results of the primary hierarchical composite outcome were maintained neutral at Week 52 [Mann–Whitney estimator 0.52, 95% confidence interval (CI) 0.45–0.59, P = 0.51]. Landmark analyses suggested late clinical benefit in patients with significant left ventricular enlargement receiving adequate dosing. Specifically, beyond 100 days of follow-up, patients with left ventricular end-diastolic volume of 200–370 mL treated with ≤19 injections of cardiopoietic stem cells showed reduced risk of death or cardiovascular hospitalization (hazard ratio 0.38, 95% CI 0.16–0.91, P = 0.031) and cardiovascular death or heart failure hospitalization (hazard ratio 0.28, 95% CI 0.09–0.94, P = 0.040). Cardiopoietic stem cell therapy was well tolerated long term with no difference in safety readouts compared with sham at 2 years. Conclusions Longitudinal follow-up documents that cardiopoietic stem cell therapy is overall safe, and post hoc analyses suggest benefit in an ischaemic heart failure subpopulation defined by advanced left ventricular enlargement on tolerable stem cell dosing. The long-term clinical follow-up thus offers guidance for future targeted trials.

Background: The FOXO3a (forkhead box O3a)-BNIP3 (B-cell lymphoma 2/adenovirus E1B 19kDa interacting protein 3) pathway modulates mitochondrial dynamics and function and contributes to myocardial remodeling in rodent models of heart failure. We sought to investigate the expression of this pathway along with the expression of mitochondrial biogenesis (PGC-1α [peroxisome proliferator-activated receptor-γ coactivator-1α]), dynamics (DRP-1 [dynamin-related protein 1], OPA-1 [optic atrophy 1], and MFN 2 [mitofusin 2]), and oxidative phosphorylation (citrate synthase and electron transport chain complexes) markers and COX IV (cytochrome C oxidase) activity in myocardium from patients with valvular or ischemic heart disease and heart failure with preserved ejection fraction (HFpEF) or heart failure with reduced ejection fraction (HFrEF). Methods and Results: Subepicardial left ventricular biopsies (10×1×1 mm 3 ) were obtained at aortic valve replacement (HFpEF AVR , n=5; and HFrEF AVR , n=4), coronary artery bypass grafting (HFpEF CABG , n=5; and HFrEF CABG , n=5), or left ventricular assist device implantation (HFrEF LVAD , n=4). Subepicardial biopsies from patients with normal left ventricular function (n=2) and from donor hearts (n=3) served as controls (normal). Relative to normal, mitochondrial fragmentation and cristae destruction were evident, and mitochondrial area was decreased in HFpEF; 1.00±0.09 versus 0.71±0.08; P =0.016. These mitochondrial morphological changes were more pronounced in HFrEF (0.54±0.06); P =0.002 HFpEF versus HFrEF. BNIP3 (monomer+dimer) expression was increased in HFpEF (3.99±2.44) and in HFrEF (5.19±1.70) relative to normal; P =0.004 and P <0.001, respectively. However, BNIP3 monomer was increased in HFrEF (4.32±1.43) compared with normal (0.99±0.06) and HFpEF (1.97±0.90); P =0.001 and 0.004, respectively. The HFrEF group uniquely showed increase in DRP-1 expression (1.94±0.38) and decreases in PGC-1α expression (0.61±0.07) and COX IV activity (0.70±0.10) relative to normal; P =0.013, P <0.001, and P <0.001, respectively, with no significant change in electron transport chain complexes expression. Conclusions: These findings in human myocardium confirm studies in rodents where contractile dysfunction is associated with activation of the FOXO3a-BNIP3 pathway and altered mitochondrial dynamics, biogenesis, and function.

Background Following pressure overload, compensatory concentric left ventricular remodeling ( CR ) variably transitions to eccentric remodeling ( ER ) and systolic dysfunction. Mechanisms responsible for this transition are incompletely understood. Here we leverage phenotypic variability in pressure overload–induced cardiac remodeling to test the hypothesis that altered mitochondrial homeostasis and calcium handling occur early in the transition from CR to ER , before overt systolic dysfunction. Methods and Results Sprague Dawley rats were subjected to ascending aortic banding, (n=68) or sham procedure (n=5). At 3 weeks post–ascending aortic banding, all rats showed CR (left ventricular volumes < sham). At 8 weeks post–ascending aortic banding, ejection fraction was increased or preserved but 3 geometric phenotypes were evident despite similar pressure overload severity: persistent CR , mild ER , and moderate ER with left ventricular volumes lower than, similar to, and higher than sham, respectively. Relative to sham, CR and mild ER phenotypes displayed increased phospholamban, S16 phosphorylation, reduced sodium‐calcium exchanger expression, and increased mitochondrial biogenesis/content and normal oxidative capacity, whereas moderate ER phenotype displayed decreased p‐phospholamban, S16, increased sodium‐calcium exchanger expression, similar degree of mitochondrial biogenesis/content, and impaired oxidative capacity with unique activation of mitochondrial autophagy and apoptosis markers ( BNIP 3 and Bax/Bcl‐2). Conclusions After pressure overload, mitochondrial biogenesis and function and calcium handling are enhanced in compensatory CR . The transition to mild ER is associated with decrease in mitochondrial biogenesis and content; however, the progression to moderate ER is associated with enhanced mitochondrial autophagy/apoptosis and impaired mitochondrial function and calcium handling, which precede the onset of overt systolic dysfunction.

The forkhead box O3a (FOXO3a) transcription factor has been shown to regulate glucose metabolism, muscle atrophy, and cell death in postmitotic cells. Its role in regulation of mitochondrial and myocardial function is not well studied. Based on previous work, we hypothesized that FOXO3a, through BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 (BNIP3), modulates mitochondrial morphology and function in heart failure (HF). We modulated the FOXO3a-BNIP3 pathway in normal and phenylephrine (PE)-stressed adult cardiomyocytes (ACM) in vitro and developed a cardiotropic adeno-associated virus serotype 9 encoding dominant-negative FOXO3a (AAV9.dn-FX3a) for gene delivery in a rat model of HF with preserved ejection fraction (HFpEF). We found that FOXO3a upregulates BNIP3 expression in normal and PE-stressed ACM, with subsequent increases in mitochondrial Ca2+, leading to decreased mitochondrial membrane potential, mitochondrial fragmentation, and apoptosis. Whereas dn-FX3a attenuated the increase in BNIP3 expression and its consequences in PE-stressed ACM, AAV9.dn-FX3a delivery in an experimental model of HFpEF decreased BNIP3 expression, reversed adverse left ventricular remodeling, and improved left ventricular systolic and, particularly, diastolic function, with improvements in mitochondrial structure and function. Moreover, AAV9.dn-FX3a restored phospholamban phosphorylation at S16 and enhanced dynamin-related protein 1 phosphorylation at S637. Furthermore, FOXO3a upregulates maladaptive genes involved in mitochondrial apoptosis, autophagy, and cardiac atrophy. We conclude that FOXO3a activation in cardiac stress is maladaptive, in that it modulates Ca2+ cycling, Ca2+ homeostasis, and mitochondrial dynamics and function. Our results suggest an important role of FOXO3a in HF, making it an attractive potential therapeutic target. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/role-of-foxo3a-in-heart-failure/ .

Abstract Aims Cardiopoiesis is a conditioning programme that aims to upgrade the cardioregenerative aptitude of patient-derived stem cells through lineage specification. Cardiopoietic stem cells tested initially for feasibility and safety exhibited signs of clinical benefit in patients with ischaemic heart failure (HF) warranting definitive evaluation. Accordingly, CHART-1 is designed as a large randomized, sham-controlled multicentre study aimed to validate cardiopoietic stem cell therapy. Methods Patients (n = 240) with chronic HF secondary to ischaemic heart disease, reduced LVEF (&lt;35%), and at high risk for recurrent HF-related events, despite optimal medical therapy, will be randomized 1:1 to receive 600 × 106 bone marrow-derived and lineage-directed autologous cardiopoietic stem cells administered via a retention-enhanced intramyocardial injection catheter or a sham procedure. The primary efficacy endpoint is a hierarchical composite of mortality, worsening HF, Minnesota Living with Heart Failure Questionnaire score, 6 min walk test, LV end-systolic volume, and LVEF at 9 months. The secondary efficacy endpoint is the time to cardiovascular death or worsening HF at 12 months. Safety endpoints include mortality, readmissions, aborted sudden deaths, and serious adverse events at 12 and 24 months. Conclusion The CHART-1 clinical trial is powered to examine the therapeutic impact of lineage-directed stem cells as a strategy to achieve cardiac regeneration in HF populations. On completion, CHART-1 will offer a definitive evaluation of the efficacy and safety of cardiopoietic stem cells in the treatment of chronic ischaemic HF. Trial registration: NCT01768702