Cardiomyopathic Hearts Research Articles

Abstract P1137: Novel Transcriptomic Interactions In Human Cardiomyopathic Heart Failure

Noncoding regions span ~98% of the human genome and are emerging as key players in cardiovascular pathologies. However, the role of human noncoding RNAs and their interactions with other RNAs and protein-coding genes in ischemic (ICM) and nonischemic cardiomyopathic (NICM) heart failure is not clear. Twenty-eight patients (53±11 years; mix of gender and race) were studied using Tukey’s analysis of variance and post-hoc analyses. Significantly increased left ventricular (LV) internal diameter (diastole and systole; p<0.01) and decreased ejection fraction (EF:p<1E-10) were observed in both ICM (EF:17.5%±3.5) and NICM (EF:20.6%±3.2) compared to organ donor controls (EF:56.6%±6). End-systolic volume was increased in ICM, and QTc and QRS duration were prolonged in NICM (p<0.05). Following blinded quality control validation of both LV RNA and data, blinded whole transcriptomics (n=4/group) revealed differential expression of numerous long noncoding (lnc)RNAs, micro(mi)RNAs, and mRNAs (p-corrected/adjusted; padj<0.05). We uncovered 251 novel lncRNAs, 137 novel mature miRNAs, and 286 novel mRNAs (padj<0.05). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Reactome and Disease Ontology enrichment analyses revealed several significant (padj<0.05) pathways in cancer, neuro/macular degeneration, neuroembryological development, endocrine, inflammation, bone remodeling, vein disease, etc. Seven lncRNA-associated protein-protein interaction networks were identified in ICM (>700 confidence score). Co-expression analysis revealed highly significant lncRNA-mRNA interactions with Pearson Correlation Coefficient of <0.95 and >0.95 with p<0.00001. GO/KEGG also revealed miRNA-mRNA interactions related to bacterial/viral, parathyroid, cancer, mTOR, etc. (padj<0.05). Importantly, several genes and interactions in all the above RNA species and multiple enrichment pathways distinguished ICM versus NICM (padj<0.05). We also observed several lncRNA alternative splicing events (padj<0.0004; false discovery rate<0.05), numerous missense and silent mutations, and minimal nonsense mutations. Together, this study offers novel transcriptomic and interactomic understanding in human ICM and NICM heart failure.

Implications of Tropomyosin Phosphorylation in Normal and Cardiomyopathic Hearts

Numerous molecular and biochemical processes regulate protein production in the cell. One of these processes, phosphorylation, allows the cell to rapidly adapt to changing physiological situations. In terminally differentiated cells, such as cardiomyocytes, phosphorylation of sarcomeric proteins controls contraction and relaxation under both normal and stressful conditions. The focus of this review is how phosphorylation of sarcomeric proteins alters physiological performance in cardiac muscle with a particular emphasis on the thin filament protein tropomyosin. This topic is addressed by the examination of tropomyosin isoform expression and its phosphorylation state from embryonic to adult murine development. Next, studies are examined which utilize in vivo model systems to express phosphorylation mimetics and de-phosphorylation genetically-altered tropomyosin transgene constructs. Results show that tropomyosin isoform expression is highly regulated, along with its phosphorylation state. Transgenic mouse hearts which express high levels of a constitutively phosphorylated tropomyosin develop a severe dilated cardiomyopathy and die within a month. A more moderate expression of this phosphorylation mimetic leads to normal systolic performance, but impaired diastolic function. When tropomyosin is dephosphorylated, the transgenic mice develop a compensated cardiac hypertrophy without systolic or diastolic alterations. Interestingly, when dephosphorylated tropomyosin is co-expressed with a hypertrophic cardiomyopathy tropomyosin mutation, the pathological phenotype is rescued with improved cardiac function and no indices of systolic or diastolic dysfunction. These studies demonstrate the functional significance of tropomyosin phosphorylation in determining cardiac performance during both normal and pathological conditions.

Long‐chain fatty acid oxidation and respiratory complex I deficiencies distinguish Barth Syndrome from idiopathic pediatric cardiomyopathy

Barth syndrome (BTHS) is an X-linked disorder that results from mutations in the TAFAZZIN gene, which encodes a phospholipid transacylase responsible for generating the mature form of cardiolipin in inner mitochondrial membranes. BTHS patients develop early onset cardiomyopathy and a derangement of intermediary metabolism consistent with mitochondrial disease, but the precise alterations in cardiac metabolism that distinguish BTHS from idiopathic forms of cardiomyopathy are unknown. We performed the first metabolic analysis of myocardial tissue from BTHS cardiomyopathy patients compared to age- and sex-matched patients with idiopathic dilated cardiomyopathy (DCM) and nonfailing controls. Results corroborate previous evidence for deficiencies in cardiolipin content and its linoleoyl enrichment as defining features of BTHS cardiomyopathy, and reveal a dramatic accumulation of hydrolyzed (monolyso-) cardiolipin molecular species. Respiratory chain protein deficiencies were observed in both BTHS and DCM, but a selective depletion of complex I was seen only in BTHS after controlling for an apparent loss of mitochondrial density in cardiomyopathic hearts. Distinct shifts in the expression of long-chain fatty acid oxidation enzymes and the tissue acyl-CoA profile of BTHS hearts suggest a specific block in mitochondrial fatty acid oxidation upstream of the conventional matrix beta-oxidation cycle, which may be compensated for by a greater reliance upon peroxisomal fatty acid oxidation and the catabolism of ketones, amino acids, and pyruvate to meet cardiac energy demands. These results provide a comprehensive foundation for exploring novel therapeutic strategies that target the adaptive and maladaptive metabolic features of BTHS cardiomyopathy.

Twin peaks diversity with sacubitril/valsartan treatment responses in cardiomyopathic heart failure patients of non-ischemic compared to ischemic etiologies

Abstract Background Ischemic cardiomyopathy (ICM) has been associated with increased mortality when compared with non-ischemic cardiomyopathy (NICM) from several heart failure (HF) cohorts. Instead, PARADIGM study demonstrated similar event rates of cardiovascular (CV) death, all-cause mortality and HF readmissions between ICM and NICM patients. Although the beneficiary effect of sacubitril/valsartan (SAC/VAL) compared to enalapril on these endpoints was consistent across etiologic categories, PARADIGM study did not analyze the effect of ventricular remodeling of SAC/VAL on patients with different HF etiologies, which may significantly affect treatment outcomes. Purpose We aim to compare alterations of left ventricular ejection fraction (LVEF) following SAC/VAL treatment and its association with clinical outcomes in patients with different HF etiologies. Methods Treatment with angiotensin receptor neprilysin inhibitor for Taiwan heart failure patients (TAROT-HF) study is a multicenter study which enrolled 1552 patients with LVEF <40%, whom had been on SAC/VAL treatment from 9 hospitals between 2017 and 2018. After excluding patients without having follow-up echocardiographic studies, patients were grouped by HF etiologies and by LVEF changes following treatment for 8-month period. LVEF improvement ≥15% was defined as “significant improvement”, 5–15% as “marginal improvement”, and <5% or worse as “lack of improvement”. The primary endpoint was a composite of CV death or a first hospitalization for HF. Mean follow-up period was 726 days. Results A total of 1230 patients were analyzed. Patients with ICM were significantly older, more male, and prone to have associated hypertension and diabetes. On the other hand, patients with NICM had lower LVEF and higher likelihood of atrial fibrillation. LVEF increase was significantly greater in patients with NICM compared to those with ICM (11.2±12.4% vs. 6.9±9.8, p<0.001). The effect of ventricular remodeling of SAC/VAL on patients with NICM showed twin peaks diversity (Significant improvement 37.1%, lack of improvement 42.3%), whereas in patients with ICM the proportions of significant, marginal and lack of improvement groups were 19.4%, 28.2% and 52.4%, respectively. The primary endpoint showed twin peaks diversity also in patients with NICM in line with LVEF changes: adjusted HR for patients with NICM and significant improvement was 0.41 (95% CI 0.29–0.57, p<0.001), for patients with NICM and lack of improvement was 1.54 (95% CI 1.22–1.94, p<0.001). Analyses for CV death, all-cause mortality, and HF readmission demonstrated consistent results. Conclusion Patients with NICM had higher degree of LVEF improvement than those with ICM following SAC/VAL treatment, and significant improvement of LVEF in NICM patients may indicate favorable outcome. NICM patients without response to SAC/VAL treatment should serve as an indicator for poor clinical outcome and warranted meticulous HF management. Funding Acknowledgement Type of funding source: Private hospital(s). Main funding source(s): Cheng Hsin General Hospital

Modulating the tension-time integral of the cardiac twitch prevents dilated cardiomyopathy in murine hearts.

Dilated cardiomyopathy (DCM) is often associated with sarcomere protein mutations that confer reduced myofilament tension–generating capacity. We demonstrated that cardiac twitch tension-time integrals can be targeted and tuned to prevent DCM remodeling in hearts with contractile dysfunction. We employed a transgenic murine model of DCM caused by the D230N-tropomyosin (Tm) mutation and designed a sarcomere-based intervention specifically targeting the twitch tension-time integral of D230N-Tm hearts using multiscale computational models of intramolecular and intermolecular interactions in the thin filament and cell-level contractile simulations. Our models predicted that increasing the calcium sensitivity of thin filament activation using the cardiac troponin C (cTnC) variant L48Q can sufficiently augment twitch tension-time integrals of D230N-Tm hearts. Indeed, cardiac muscle isolated from double-transgenic hearts expressing D230N-Tm and L48Q cTnC had increased calcium sensitivity of tension development and increased twitch tension-time integrals compared with preparations from hearts with D230N-Tm alone. Longitudinal echocardiographic measurements revealed that DTG hearts retained normal cardiac morphology and function, whereas D230N-Tm hearts developed progressive DCM. We present a computational and experimental framework for targeting molecular mechanisms governing the twitch tension of cardiomyopathic hearts to counteract putative mechanical drivers of adverse remodeling and open possibilities for tension-based treatments of genetic cardiomyopathies.

Human Cardiac Organoids for Modeling Genetic Cardiomyopathy.

Genetic cardiomyopathies are characterized by changes in the function and structure of the myocardium. The development of a novel in vitro model could help to better emulate healthy and diseased human heart conditions and may improve the understanding of disease mechanisms. In this study, for the first time, we demonstrated the generation of cardiac organoids using a triculture approach of human induced pluripotent stem-cell-derived cardiomyocytes (hiPS-CMs)—from healthy subjects and cardiomyopathy patients—human cardiac microvascular endothelial cells (HCMECs) and human cardiac fibroblasts (HCFs). We assessed the organoids’ suitability as a 3D cellular model for the representation of phenotypical features of healthy and cardiomyopathic hearts. We observed clear differences in structure and beating behavior between the organoid groups, depending on the type of hiPS-CMs (healthy versus cardiomyopathic) used. Organoids may thus prove a promising tool for the design and testing of patient-specific treatments as well as provide a platform for safer and more efficacious drug development.

Importance of Mitochondrial-Related Genes in Dilated Cardiomyopathy Based on Bioinformatics Analysis

We designed this study to identify potential key protein interaction networks, genes, and correlated pathways in dilated cardiomyopathy (DCM) via bioinformatics methods. We selected the GSE3586 microarray dataset, consisting of 15 dilated cardiomyopathic heart biopsy samples and 13 nonfailing heart biopsy samples. Initially, the GSE3586 dataset was downloaded and was analyzed with the limma package to identify differentially expressed genes (DEGs). A total of 172 DEGs consisting of 162 upregulated genes and ten downregulated genes in DCM were selected by the criterion of adjusted Pvalues less than 0.01 and the log2-fold change of 0.6 or greater. Gene Ontology functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed to view the biological processes, cellular components, molecular function, and KEGG pathways of the DEGs. Next, protein-protein interactions were constructed, and the hub protein modules were identified. Then we selected the key genes DLD, UQCRC2, DLAT, SUCLA2, ATP5A1, PRDX3, FH, SDHD, and NDUFV1, which are involved in a wide range of biological activities, such as the citrate cycle, oxidation-reduction processes and cellular respiration, and energy derivation by oxidation of organic compounds in mitochondria. Finally, we found that currently there are no related gene-targeting drugs after exploring the predicted interactions between key genes and drugs, and transcription factors. In conclusion, our study provides greater understanding of the pathogenesis and underlying molecular mechanisms in DCM. This contributes to the exploration of potential gene therapy targets.

Corrigendum to "Evaluating the Hemodynamical Response of a Cardiovascular System under Support of a Continuous Flow Left Ventricular Assist Device via Numerical Modeling and Simulations".

[This corrects the article DOI: 10.1155/2013/986430.].

Unc-51 like autophagy activating kinase 1 accelerates angiotensin II-induced cardiac hypertrophy through promoting oxidative stress regulated by Nrf-2/HO-1 pathway

Unc-51 like autophagy activating kinase 1 (ULK1) is a serine/threonine kinase and the mammalian functional homolog of yeast Atg1, and plays an essential role in regulating various cellular processes. However, whether ULK1 can influence cardiac hypertrophy is unclear. In the study, we investigated the role of ULK1 in the pathogenesis of pathological cardiac hypertrophy and the molecular mechanism. We showed that ULK1 levels were increased in human dilated cardiomyopathic hearts and in mouse hypertrophic hearts. ULK1 knockout conferred resistance to angiotensin II (Ang II) infusion through markedly repressing hypertrophic growth, cardiac function and the deposition of fibrosis. In ULK1 transgenic (TG) mice with ULK1 over-expression, accelerated hypertrophy, reduced cardiac function and promoted fibrosis deposition were observed compared with non-transgenic mice following AngII challenge. In addition, mice lacking ULK1 showed alleviated oxidative stress by improving nuclear erythroid factor 2-related factor 2 (Nrf-2) and heme oxygenase-1 (HO-1) expression, whereas mice with ULK1 over-expression developed an accelerated reactive oxygen species (ROS) production. In vitro, we found that ULK1 knockdown-attenuated oxidative stress, inflammation and fibrosis deposition in AngII-exposed cardiomyocytes were significantly blunted by the inhibition of Nrf-2/HO-1 signaling. However, ULK1 overexpression-accelerated oxidative stress, inflammatory response and fibrosis were markedly ameliorated by the inhibition of ROS production. Our results indicated that ULK1 was a potential therapeutic target in pathological cardiac hypertrophy.

Catheter Ablation Versus Non-Ablative Strategies for Ventricular Tachycardia in Patients with Ischemic Cardiomyopathy on Implantable Cardioverter-Defibrillator: A Systematic Review and Meta-Analysis

Background: Ventricular tachycardia (VT) is an abnormal rapid rhythm originating from the lower ventricles occurring commonly in patients with cardiomyopathic hearts. Three treatment options are available: implantable cardioverter defibrillator (ICD), antiarrhythmic medications or catheter ablation (or a combination of these options). This systematic review aimed to compare the efficacy of catheter ablation vs non-ablative techniques as treatment for VT in patients with ischemic cardiomyopathy. Methods: This was a systematic review and meta-analysis of prospective studies that compared ablative vs non-ablative strategies in patients with ischemic heart disease and depressed left ventricular ejection fraction (LVEF). Outcomes of interest included the post-treatment rate of recurrent VT, appropriate ICD shocks and mortality. Results: Pooled findings of five studies showed a non-significant difference in the odds of VT post-treatment between the ablation arm and the non-ablation arm (OR 0.61; 95% CI 0.34-1.10; p=0.10). Heterogeneity was high (I2=55%). Sensitivity analysis excluding one pilot study contributing to the heterogeneity revealed a statistically significant reduction in the odds of recurrent VT (OR 0.54; 95% CI 0.31-0.94; p=0.0.03). Pooled findings of four studies showed that ablation resulted in a lower rate of appropriate shocks post-treatment compared with the non-ablative group (OR 0.51; 95% CI 0.30-0.87; p=0.01. There was no significant difference in the mortality rate between catheter ablation and non-ablative strategies (OR 0.77; 95% CI 0.47-1.25; p=0.29). Conclusion: Catheter ablation on top of ICD placement reduced the risk of post-treatment VT and appropriate shocks. However, these did not translate into a reduction in mortality. KEYWORDS: catheter ablation, non-ablative strategies, implantable cardioverter defibrillator, ischemic cardiomyopathy.

CARDIOPROTECTIVE EFFECT OF TUMOR NECROSIS FACTOR ALPHA ANTAGONIST IN DOXORUBICIN MYOCARD TOXICITY

Doxorubicin (Dox) is a first line drug in neoplasia treatment. It is however cardiotoxic even in moderate dosages. High mortality of oncological patients from cardiomyopathic heart failure on Dox treament is a serious problem of oncology and cardiology. Among the cardiotoxicity factors of Dox are activation of inflammatory reaction and ability of the drug to increase expression of tumor necrosis factor alpha (TNF-a) in myocardium and coronary arteries. Aim. To study in laboratory conditions the opportunities for cardioprotection from Dox with TNF-a antagonist. Material and methods. Doxorubicin myocardial damage (DMD) was simulated on the white rats by intraabdominal load of Dox in cumulative dosage 16 mg/kg within 2 weeks. In other series, to the animals together with Dox every day during 2 weeks intraabdominally the TNF-a antagonist was loaded — monoclonal antibody (ma-TNF-a) dosage 5,0 mg/kg. Cardioprotective effect ma-TNF-a was evaluated on the perfusion model of the isolated heart with assessment of: (1) inotropic response of myocardium on stimulation by noradrenalin and endothelin-1 (ET-1); (2) coronary functional reserve on acetylcholine, adenosine, bradikinine and hydrogen peroxide influence; (3) dynamics of end diastolic pressure (EDP) of the left ventricle in the ischemia-reperfusion syndrome. Results. In DMD, there was significant disorder of the diastole, systole and pumping function of the heart even in physiological values of filling and resistance. Action ma-TNF-a was followed by a significant increase of cardiac output, maximum velocity of isovolumetric contraction and relaxation by 14,2-26,3%, and significant decrease of EDP by 30,1%. With action of ET-1 on the heart with DMD there was negative inotropic effect, mediated by the decrease of systolic pressure (SP) in LV by 9,1% comparing to the baseline, and when ma-TNF-a made analogically to control positive inotropic effect (SP in LV increased by 8,5%) and increase of cardiac output by 14,3%. Cardioprotective effect of ma-TNFa followed by significant increase of coronary functional reserve. It is notable that coronary reactivity, common for the action hydrogen peroxide and mediated by hyperpolarization, did not change in DMD. Usage of ma-TNF-a improved resistance of the heart to ischemia and reperfusion, as the measured EDP values measured at various time frames were significantly lower than EDP, and the level of SP in LV — significantly higher. Conclusion. Usage of TNF-a antagonist in DMD made cardioprotective effect: significant increase of cardiac output, SP, maximum velocity of isovolumetric contraction and relaxation, significant decrease of EDP, appearance of postitive inotropic response of the heart on ET-1, and improvement of endothelium-dependent coronary dilation. Action of ma-TNF-a was followed by decrease of ischemic cardiac contracture and significantly better recovery of SP and EDP during reperfusion.

Management of Complex Ventricular Arrhythmias in Heterotopic Heart Transplant Patients

A 55-year-old woman was admitted with palpitations on a background of heterotopic heart transplantation 13 years earlier. Prior to transplant, a dual-chamber permanent pacemaker was implanted in her native heart for a severe ischaemic cardiomyopathy with a left ventricular ejection fraction of 5%. Post-transplant, our patient's donor heart had been affected by both allograft vasculopathy requiring percutaneous coronary intervention and one episode of cellular rejection. Her current donor left ventricular ejection fraction was 40%. Our patient's palpitations were identified as recurrent episodes of native heart ventricular tachycardia lasting up to 21 hours at rates of 180 beats per minute. Direct cardioversion to the native heart was performed twice, unsuccessfully. Amiodarone infusion also failed to control the burden of ventricular tachycardia. Lignocaine was then added, but at this point the patient developed bradycardia in the donor heart. In the setting of competing native tachycardia and donor bradycardia, our patient developed cardiogenic shock due to her doubly low-output state. Further cardioversion to the native heart was considered too high risk given the new donor bradycardia. A dual-chamber permanent pacemaker was implanted into the donor heart. Anti-tachycardic therapy was optimised to bisoprolol, oral amiodarone, and mexiletine. With aggressive anti–arrhythmic therapy, ventricular arrhythmias in the native heart ceased while the donor heart was supported with pacing. This is the first report of double dual-chamber pacemakers being implanted in a heterotopic heart transplant recipient to treat complex competing arrhythmias. This case emphasises the difficult balance of controlling two connected cardiomyopathic hearts developing conflicting arrhythmias.

Distinct fibrosis pattern in desmosomal and phospholamban mutation carriers in hereditary cardiomyopathies

Desmosomal and phospholamban (PLN) mutations are associated with arrhythmogenic cardiomyopathy. Ultimately, most cardiomyopathic hearts develop significant cardiac fibrosis. To compare the fibrosis patterns of desmosomal and p. Arg14del PLN-associated cardiomyopathies with the pattern in hearts with other hereditary cardiomyopathies. A midventricular transversal slice was obtained from hearts of 30 patients with a cardiomyopathy with a known underlying mutation and from 8 controls. Fibrosis and fatty changes were quantitatively analyzed using digital microscopy. Hearts from patients with desmosomal mutations (n=6) showed fibrosis and fibrofatty replacement in the left ventricular (LV) outer myocardium, mainly in the posterolateral wall, and in the right ventricle. A similar phenotype, but with significantly more severe fibrotic changes in the LV, was found in the PLN mutation group (n = 8). Cardiomyopathies associated with lamin A/C (n= 5), sarcomeric (n = 8), and desmin (n = 3) mutations all showed a different pattern from that of the desmosomal and PLN mutation carriers. The posterolateral LV wall appeared to be the most discriminative area with fibrosis andfatty changes predominantly at the outer compact myocardium in 13 of 14 hearts with desmosomal and PLN mutations (93%), in 0 of 13 hearts with lamin A/C and sarcomeric mutations (0%), and in 1 of 3 desminopathic hearts (33%) (P<.001). Desmosomal- and PLN-associated cardiomyopathies have a fibrosis pattern distinct from the patterns in other hereditary cardiomyopathies. The posterolateral LV wall appeared to be the most discriminative region between mutation groups. These results may provide a roadmap for cardiac imaging interpretation and may help in further unraveling disease mechanisms.

Abstract P5-14-12: Long-term outcome of HER2-normal early stage breast cancer (ESBC) patients (Pts) treated with docetaxel-cyclophosphamide (TC) chemotherapy (CTx): Mature results of a single-institution experience

Abstract BACKGROUND Anthracycline(A)-containing regimens (AReg) became an established standard (neo)adj CTx for ESBC following fairly consistent demonstration of a modest superiority over older anti-metabolite/alkylating CTx. However, substantial translational data and a recently presented pooled analysis [Blum, 2016] suggest that this superiority could be largely driven by greater benefits in specific ESBC subgroups, i.e. HER2-altered BrCa (due to co-amplification of topoisomerase 2 and HER2), and triple-negative BrCa (TNBC). A are cardiotoxic (including late onset of cardiomyopathic congestive heart failure) and potentially leukaemogenic. In late 2006, following the results of the first USONC randomized clinical trial that showed superior outcomes of the non-AReg TC (docetaxel/cyclo­phosphamide) over AC, we established a routine, uniform policy of TC for all Pts receiving (neo)adj CTx for HER2-normal ESBC. We report the mature follow up of this single-institution unselected experience. METHODS We performed a retrospective outcome analysis of all Pts who received at least 1 cycle of (neo)adj TC (docetaxel 75 mg/m2 + cyclophosphamide 600 mg/m2 IV every 3 weeks) at our Department for HER2-normal ESBC and with at least 5 years of follow up (FU). Pts were identified by systematic analysis of the dataset of the Oncology Pharmacy Unit. Information on tumour characteristics [e.g. axillary lymph nodes (N) metastases, hormonal receptors (HR) and HER2 status] and Pts FU were retrieved and collected into an ad hoc designed database. Pts with node-positive (N+) ESBC received TC×6 cycles, and Pts with high-risk node-negative (N−) [e.g. primary tumour (T) &amp;gt;2 cm, or HRneg, or T &amp;gt;3 cm] ESBC received TC×4 cycles. Pts received adjuvant hormone therapy and radiotherapy as per standard of care. From 2008 on, many lower risk HR+/N− Pts were not given CTx due to OncotypeDx availability. RESULTS Between September 2006 and December 2015, 810 female HER2-normal ESBC Pts were treated with (neo)adj TC. In the final outcome analysis we included 464 Pts treated before June 2011 thus having a minimum FU of 5 years. Pts characteristics are: median age 53 yrs (range 30-77), N− 246 (53%), N+ 218 (47%), hormone receptors positive (HR+) 391 (84%), TNBC 73 (16%). The database was locked as of June 1st 2016. Median FU from first cycle of TC is 7.5 yrs (range 5.3-10). 63 BrCa-specific relapse events (defined as time to local, regional or distant recurrence, invasive contralateral breast cancer, excluding non-breast second primaries) have been observed, accounting for an overall Relapse-Free Survival (RFS) rate of 86.4%. 42 deaths have occurred, 36 (86%) due to BrCa, accounting for an Overall Survival (OS) rate of 91%. RFS and OS rates for the different Pts subgroups are reported in Table 1 Table 1 - Outcome parameters RFS (%)OS (%)All Pts8691HR+/N-9396HR+/N+8190TN/N-9191TN/N+5858 CONCLUSIONS These mature data with long FU suggest that the outcome for a large cohort of unselected Pts with HER2-normal HR+ ESBC (regardless of nodal status) and for TN/N− ESBrCa treated with nonAReg TC is excellent. However, N+TN ESBrCa in this setting remains a significant clinical challenge. Citation Format: Losurdo A, Gullo G, Buckley C, Lowry C, Ballot J, Silva N, Hammond L, Crown J. Long-term outcome of HER2-normal early stage breast cancer (ESBC) patients (Pts) treated with docetaxel-cyclophosphamide (TC) chemotherapy (CTx): Mature results of a single-institution experience [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-14-12.

Smad Nuclear Interacting Protein 1 Acts as a Protective Regulator of Pressure Overload-Induced Pathological Cardiac Hypertrophy.

BackgroundSmad nuclear interacting protein 1 (SNIP1) plays a critical role in cell proliferation, transformation of embryonic fibroblasts, and immune regulation. However, the role of SNIP1 in cardiac hypertrophy remains unclear.Methods and ResultsHere we examined the role of SNIP1 in pressure overload–induced cardiac hypertrophy and its mechanisms. Our results demonstrated that SNIP1 expression was downregulated in human dilated cardiomyopathic hearts, aortic banding‐induced mice hearts, and angiotensin II–treated cardiomyocytes. Accordingly, SNIP1 deficiency significantly exacerbated aortic banding–induced cardiac hypertrophy, fibrosis, and contractile dysfunction, whereas cardiac‐specific overexpression of SNIP1 markedly recovered pressure overload–induced cardiac hypertrophy and fibrosis. Besides that, SNIP1 protected neonatal rat cardiomyocytes against angiotensin II–induced hypertrophy in vitro. Moreover, we identified that SNIP1 suppressed nuclear factor‐κB signaling during pathological cardiac hypertrophy, and inhibition of nuclear factor‐κB signaling by a cardiac‐specific conditional inhibitor of κBS 32A/S36A transgene blocked these adverse effects of SNIP1 deficiency on hearts.ConclusionsTogether, our findings demonstrated that SNIP1 had protective effects in pressure overload–induced pathological cardiac hypertrophy via inhibition of nuclear factor‐κB signaling. Thus, SNIP1 may be a novel approach for the treatment of heart failure.

Electrical effects of stem cell transplantation for ischaemic cardiomyopathy: friend or foe?

Despite advances in other realms of cardiac care, the mortality attributable to ischaemic cardiomyopathy has only marginally decreased over the last 10years. These findings highlight the growing realization that current pharmacological and device therapies rarely reverse disease progression and rationalize a focus on novel means to reverse, repair and re-vascularize damaged hearts. As such, multiple candidate cell types have been used to regenerate damaged hearts either directly (through differentiation to form new tissue) or indirectly (via paracrine effects). Emerging literature suggests that robust engraftment of electrophysiolgically heterogeneous tissue from transplanted cells comes at the cost of a high incidence of ventricular arrhythmias. Similar electrophysiological studies of haematological stem cells raised early concerns that transplant of depolarized, inexcitable cells that also induce paracrine-mediated electrophysiological remodelling may be pro-arrhythmic. However, meta-analyses suggest that patients receiving haematological stem cells paradoxically may experience a decrease in ventricular arrhythmias, an observation potentially related to the extremely poor long-term survival of injected cells. Finally, early clinical and preclinical data from technologies capable of differentiating to a mature cardiomyocyte phenotype (such as cardiac-derived stem cells) suggests that these cells are not pro-arrhythmic although they too lack robust long-term engraftment. These results highlight the growing understanding that as next generation cell therapies are developed, emphasis should also be placed on understanding possible anti-arrhythmic contributions of transplanted cells while vigilance is needed to predict and treat the inadvertent effects of regenerative cell therapies on the electrophysiological stability of the ischaemic cardiomyopathic heart.

Growth Arrest-Specific 6 Exacerbates Pressure Overload-Induced Cardiac Hypertrophy.

Growth arrest-specific 6 (GAS6) is a member of the vitamin K-dependent protein family that is involved in the regulation of the cardiovascular system, including vascular remodeling, homeostasis, and atherosclerosis. However, there is still no study that systemically elucidates the role of GAS6 in cardiac hypertrophy. Here, we found that GAS6 was upregulated in human dilated cardiomyopathic hearts, hypertrophic murine hearts, and angiotensin II-treated cardiomyocytes. Next, we examined the influence of GAS6 expression in response to a cardiac stress by inducing chronic pressure overload with aortic banding in wild-type and GAS6-knockout mice or cardiac-specific GAS6 overexpressing mice. Under basal conditions, the GAS6-knockout mice had normal left ventricular structure and function but after aortic banding, the mice demonstrated less hypertrophy, fibrosis, and contractile dysfunction when compared with wild-type mice. Conversely, cardiac-specific overexpression of GAS6 exacerbated aortic banding-induced cardiac hypertrophy, fibrosis, and dysfunction. Furthermore, we demonstrated that GAS6 activated the mitogen-activated protein kinase kinase 1/2-extracellular signal-regulated kinase 1/2 pathway during pressure overload-induced cardiac hypertrophy, and the pharmacological mitogen-activated protein kinase kinase 1/2 inhibitor U0126 almost completely reversed GAS6 overexpression-induced cardiac hypertrophy and fibrosis, resulting in improved cardiac function. Collectively, our data support the notion that GAS6 impairs ventricular adaptation to chronic pressure overload by activating mitogen-activated protein kinase kinase 1/2-extracellular signal-regulated kinase 1/2 signaling. Our findings suggest that strategies to reduce GAS6 activity in cardiac tissue may be a novel approach to attenuate the development of congestive heart failure.

38 A new age of idiopathic dilated cardiomyopathy: exploration and development of a genetic consensus

Introduction Despite the advances in genetic analysis and the increasing availability of analytical technologies, the genetic aetiology of Idiopathic (non-familial) Dilated Cardiomyopathy is poorly understood. Microarray analysis allows the simultaneous analysis of up to 40,000 gene products, effectively describing the entire expression profile of a biological sample. Public gene expression repositories (PGER) house microarray expression data from over 50,000 individual experiments comprising 1,300,000 samples. This offers a powerful, and as of yet not fully utilised, resource in establishing an intracellular pathogenesis in poorly understood disease states. Objective The main aim was to utilise PGERs to generate and test genetic expression profiles differentiating normal and cardiomyopathic hearts, and use this data to identify key intracellular pathways which have become dysfunctional. Methods A search was conducted across PGERs for experiments differentiating hearts with idiopathic cardiomyopathy and normal controls. Following a filtration process, nine experiments were considered suitable for analysis. Raw genetic expression data was extracted from the microarray repositories and analysed for each experiment using R statistical software. The frequencies of genes which were significantly dysregulated from controls were compared across all nine experiments using de novo visual basic script (VBS) code. Enrichment analysis was conducted using Ingenuity pathway software. Results A total of 23,967 genes were dysregulated in dilated cardiomyopathy across all experiments (Table 1). Frequency analysis identified genes occuring most commonly, and these were categorised whether the genes were up-regulated or down-regulated (Table 2). Enrichment analysis allowed the identification of specific pathways which were observed to become up- and down-regulated in at least 66% (6 out of nine experiments) (Figure 1). Pathways which were seen to be up-regulated in DCM have been associated with: 1) Immune cell infiltration effects seen in rheumatoid arthritis, 2) c-AMP signalling, 3) Cardiac B-Adrenergic signalling, 4) Glucocorticoid receptor signalling, 5) VDR/RXR activation, and 6) HGF signalling (Figure 1). Pathways down-regulated were 1) PTEN signalling, 2) Protein Kinase A signalling, and 3) the STAT3 Pathway. Conclusions Microarray data in PGER was used successfully to establish genetic consensus in identifying key intracellular pathways which have become dysregulated in idiopathic dilated cardiomyopathy. This novel type of meta-analytical technique shows promise in establishing intracellular aetiology in systemic pathology.

Abstract 111: NEDD8 Ultimate Buster-1 Long (NUB1L) Protein Regulates Atypical Neddylation and Protects Against Myocardial Ischemia-reperfusion Injury

Neddylation is a ubiquitination-like pathway that covalently conjugates NEDD8 to target proteins and involves in diverse cellular processes. Under stress conditions, NEDD8 forms a chain or mixes with ubiquitin to modify protein substrates in NEDD8 conjugating enzymes-independent manner (atypical neddylation). The functional consequence of atypical neddylation remains unexplored in any cell types including cardiomyocytes. Here we report that increased neddylated proteins were observed in desmin-related cardiomyopathic (DRC) mouse hearts, mouse hearts subjected to myocardial ischemia-reperfusion (I/R) and human failing hearts. In cultured cardiomyocytes, multiple cellular stresses induced atypical neddylation, which was attenuated by NUB1L overexpression but exaggerated by loss of NUB1L, revealing NUB1L as a negative regulator of atypical neddylation. Activation of atypical neddylation by forced expression of NEDD8 accumulated a proteasome surrogate substrate GFPu, while suppression of atypical neddylation by NUB1L overexpression enhanced the degradation of GFPu and a DRC-linking misfolded protein. NUB1L is necessary and sufficient to protect cardiomyocytes against proteotoxic stress-induced cell injury. In vivo, cardiac-specific overexpression of NUB1L (NUB1L-O/E) in mice dose-dependently reduced neddylated proteins and facilitated the degradation of the proteasome surrogate substrate. NUB1L-O/E mice displayed no discernible cardiac structural and functional abnormality at baseline, but exihibted reduced apoptotic cardiomyocytes, limited infarct sizes and preserved cardiac function in response to I/R. We therefore conclude that NUB1L suppresses atypical neddylation, enhances proteasome proteolytic function and protects against myocardial I/R injury. Targeting atypical neddylation could be a novel therapeutic strategy to treat cardiac ischemic cardiomyopathy.

SINGLE CELL ENCAPSULATION IMPROVES STEM CELL RETENTION AND CELL-MEDIATED CARDIAC REPAIR

SINGLE CELL ENCAPSULATION IMPROVES STEM CELL RETENTION AND CELL-MEDIATED CARDIAC REPAIR