Identification of Signature Genes of Dilated Cardiomyopathy Using Integrated Bioinformatics Analysis.

Dilated cardiomyopathy (DCM) is characterized by left ventricular or biventricular enlargement with systolic dysfunction. To date, the underlying molecular mechanisms of dilated cardiomyopathy pathogenesis have not been fully elucidated, although some insights have been presented. In this study, we combined public database resources and a doxorubicin-induced DCM mouse model to explore the significant genes of DCM in full depth. We first retrieved six DCM-related microarray datasets from the GEO database using several keywords. Then we used the "LIMMA" (linear model for microarray data) R package to filter each microarray for differentially expressed genes (DEGs). Robust rank aggregation (RRA), an extremely robust rank aggregation method based on sequential statistics, was then used to integrate the results of the six microarray datasets to filter out the reliable differential genes. To further improve the reliability of our results, we established a doxorubicin-induced DCM model in C57BL/6N mice, using the "DESeq2" software package to identify DEGs in the sequencing data. We cross-validated the results of RRA analysis with those of animal experiments by taking intersections and identified three key differential genes (including BEX1, RGCC and VSIG4) associated with DCM as well as many important biological processes (extracellular matrix organisation, extracellular structural organisation, sulphur compound binding, and extracellular matrix structural components) and a signalling pathway (HIF-1 signalling pathway). In addition, we confirmed the significant effect of these three genes in DCM using binary logistic regression analysis. These findings will help us to better understand the pathogenesis of DCM and may be key targets for future clinical management.

Clinical characterization and natural history of chemotherapy-induced dilated cardiomyopathy.

AIMS: Chemotherapy-induced dilated cardiomyopathy (CI-DCM) is a well-recognized phenotype of non-ischemic dilated cardiomyopathy (DCM), characterized by poor outcomes. However, a detailed comparison between idiopathic DCM (iDCM) and CI-DCM is still lacking. METHODS AND RESULTS: All consecutive DCM patients enrolled in the Trieste Muscle Heart Disease Registry were analysed. CI-DCM and iDCM were defined according to current recommendations. The primary study outcome measure was all-mortality death and secondary outcomes were a) a composite of cardiovascular death/heart-transplantation/ventricular-assist-device implantation, and b) major ventricular arrhythmias. The study included 551 patients (499 iDCM and 52 CI-DCM). At enrolment, compared with iDCM, CI-DCM patients were older (51 ± 14 years vs. 58 ± 3 years, respectively, P < 0.001) and had a higher left ventricular ejection fraction (32% ± 9 vs. 35% ± 10, respectively, P = 0.03). Over a median follow-up of 90 months (IQR 54-140 months), CI-DCM patients had a higher incidence of all-cause mortality compared with iDCM (36.5% vs. 8.4% in CI-DCM and iDCM respectively, P < 0.001), while the incidence of major ventricular arrhythmias was higher in the iDCM group compared with CI-DCM (4% vs. 0%, in CI-DCM and iDCM respectively, P = 0.03). The risk of the composite outcome was comparable between the two groups (P = 0.91). At Cox multivariable analysis, the diagnosis of CI-DCM emerged as independently associated to primary outcome (HR 6.42, 95% C.I. 2.52-16.31, P < 0.001). CONCLUSIONS: In a well-selected DCM cohort, patients with a chemotherapy-induced aetiology had a higher incidence of all-cause mortality compared with iDCM. Conversely, the incidence of life-threatening ventricular arrhythmic events was higher among patients with iDCM.

Mitochondrial Sirtuin-3 (SIRT3) Prevents Doxorubicin-Induced Dilated Cardiomyopathy by Modulating Protein Acetylation and Oxidative Stress.

BACKGROUND: High doses of doxorubicin put cancer patients at risk for developing dilated cardiomyopathy. Previously, we showed that doxorubicin treatment decreases SIRT3 (sirtuin 3), the main mitochondrial deacetylase and increases protein acetylation in rat cardiomyocytes. Here, we hypothesize that SIRT3 expression can attenuate doxorubicin induced dilated cardiomyopathy in vivo by preventing the acetylation of mitochondrial proteins. METHODS: Nontransgenic, M3-SIRT3 (truncated SIRT3; short isoform), and M1-SIRT3 (full-length SIRT3; mitochondrial localized) transgenic mice were treated with doxorubicin for 4 weeks (8 mg/kg body weight per week). Echocardiography was performed to assess cardiac structure and function and validated by immunohistochemistry and immunofluorescence (n=4-10). Mass spectrometry was performed on cardiac mitochondrial peptides in saline (n=6) and doxorubicin (n=5) treated hearts. Validation was performed in doxorubicin treated primary rat and human induced stem cell derived cardiomyocytes transduced with adenoviruses for M3-SIRT3 and M1-SIRT3 and deacetylase deficient mutants (n=4-10). RESULTS: Echocardiography revealed that M3-SIRT3 transgenic mice were partially resistant to doxorubicin induced changes to cardiac structure and function whereas M1-SIRT3 expression prevented cardiac remodeling and dysfunction. In doxorubicin hearts, 37 unique acetylation sites on mitochondrial proteins were altered. Pathway analysis revealed these proteins are involved in energy production, fatty acid metabolism, and oxidative stress resistance. Increased M1-SIRT3 expression in primary rat and human cardiomyocytes attenuated doxorubicin-induced superoxide formation, whereas deacetylase deficient mutants were unable to prevent oxidative stress. CONCLUSIONS: Doxorubicin reduced SIRT3 expression and markedly affected the cardiac mitochondrial acetylome. Increased M1-SIRT3 expression in vivo prevented doxorubicin-induced cardiac dysfunction, suggesting that SIRT3 could be a potential therapeutic target for mitigating doxorubicin-induced dilated cardiomyopathy.

Oridonin enhances antitumor effects of doxorubicin in human osteosarcoma cells.

BACKGROUND: Doxorubicin is the chemotherapeutic drug of choice in osteosarcoma treatment, but its cumulative administration causes dilated cardiomyopathy. Combination therapy represents a potential strategy to reduce the therapeutic dosage of the chemotherapeutic agent and minimize its side effects. The aim of this study was to evaluate the potential of oridonin, a natural product from the medicinal herb Rabdosia rubescens, to act in combination with doxorubicin for osteosarcoma treatment. To date, there are no reports of the simultaneous administration of both drugs in osteosarcoma therapy. METHODS: The combined administration of different doses of oridonin and doxorubicin, as compared with the drugs alone, were tested in an in vitro model of osteosarcoma. The synergistic effect of the drugs on cell death was assessed by alamarBlue™ and by CompuSyn software. Early and late apoptosis markers (JC-1 fluorescence and Annexin V immunofluorescence), as well as the production of reactive oxygen species, were evaluated by flow cytometry. Western blot was used to assess the expression of anti-apoptotic proteins. RESULTS: Oridonin and doxorubicin presented a synergistic cytotoxic effect in osteosarcoma cells. In the presence of sub-cytotoxic concentrations of the natural product, there was an increased accumulation of intracellular doxorubicin, increased levels of reactive oxygen species (ROS), alteration of mitochondria membrane potential and a higher rate of apoptosis. CONCLUSION: The combined use of oridonin and doxorubicin could help to reduce the clinical dosage of doxorubicin and its dangerous side effects.

Heavy Burden of Toxic Dilated Cardiomyopathy Among Young Adults: A Retrospective Study and Review of the Literature.

BACKGROUND: Dilated cardiomyopathy (DCM) is a well described entity for heart failure (HF) with reduced left ventricular ejection fraction (LVEF). Recently, drugs and other substance of abuse have been recognised as potential triggers for DCM. The aim of this study was to assess the survival in patients ≤ 65 years of age with toxic cardiomyopathy (TCM). Left ventricular remodelling and the potential usefulness of left ventricular assist devices (LVADs) was also assessed. METHODS: This was a single-centre retrospective study from January 2003 to August 2019 of 553 patients ≤ 65 years old with LVEF < 40% at a tertiary-care cardiology centre. RESULTS: A total of 201 patients (36%) had a diagnosis of idiopathic DCM. Further analysis identified 38 patients (19%) for which a TCM was the most likely etiology (amphetamine [50%], cocaine [37%], anabolic steroids [8%], and energy drinks [5%]). Despite a mean LVEF of 17 ± 8% at presentation, most patients (n = 27; 71%) had event-free survival with guideline-directed medical therapy, and 61% (n = 23) recovered an LVEF ≥ 40% after a median follow-up of 21 ± 23 months. Seven patients (18%) required an LVAD and 1 patient (3%) a transplantation. All LVADs were explanted or decommissioned after partial or complete LVEF recovery after a median support time of 11 ± 4 months. CONCLUSIONS: TCM induced by substance abuse is a frequent cause of HF, accounting for almost 20% of patients ≤ 65 years of age with DCM of unknown etiology. Treatment must be tailored on an individual basis. Mechanical circulatory support demonstrated its usefulness in carefully selected patients.

Cardiomyogenic Differentiation Potential of Human Dilated Myocardium-Derived Mesenchymal Stem/Stromal Cells: The Impact of HDAC Inhibitor SAHA and Biomimetic Matrices.

Dilated cardiomyopathy (DCM) is the most common type of nonischemic cardiomyopathy characterized by left ventricular or biventricular dilation and impaired contraction leading to heart failure and even patients' death. Therefore, it is important to search for new cardiac tissue regenerating tools. Human mesenchymal stem/stromal cells (hmMSCs) were isolated from post-surgery healthy and DCM myocardial biopsies and their differentiation to the cardiomyogenic direction has been investigated in vitro. Dilated hmMSCs were slightly bigger in size, grew slower, but had almost the same levels of MSC-typical surface markers as healthy hmMSCs. Histone deacetylase (HDAC) activity in dilated hmMSCs was 1.5-fold higher than in healthy ones, which was suppressed by class I and II HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) showing activation of cardiomyogenic differentiation-related genes alpha-cardiac actin (ACTC1) and cardiac troponin T (TNNT2). Both types of hmMSCs cultivated on collagen I hydrogels with hyaluronic acid (HA) or 2-methacryloyloxyethyl phosphorylcholine (MPC) and exposed to SAHA significantly downregulated focal adhesion kinase (PTK2) and activated ACTC1 and TNNT2. Longitudinal cultivation of dilated hmMSC also upregulated alpha-cardiac actin. Thus, HDAC inhibitor SAHA, in combination with collagen I-based hydrogels, can tilt the dilated myocardium hmMSC toward cardiomyogenic direction in vitro with further possible therapeutic application in vivo.

Serine mutations in overexpressed Hsp27 abrogate the protection against doxorubicin-induced p53-dependent cardiac apoptosis in mice.

Small heat shock proteins (sHsps) protect the heart from chemotherapeutics-induced heart failure by inhibiting p53-dependent apoptosis. However, mechanism of such protection has not been elucidated yet. Here we test a hypothesis that serine phosphorylation of sHsps is essential to inhibit the doxorubicin-induced and p53-dependent apoptotic pathway. Three transgenic mice (TG) lines with cardiomyocyte-specific overexpression of human heat shock protein 27 (hHsp27), namely, wild-type [myosin heavy chain (MHC)-hHsp27], S82A single mutant [MHC-mut-hHsp27(S82A)], and trimutant [MHC-mut-hHsp27(S15A/S78A/S82A)] were generated. TG mice were treated with Dox (6 mg/kg body wt; once in a week; 4 wk) along with age-matched nontransgenic (non-TG) controls. The Dox-treated MHC-hHsp27 mice showed improved survival and cardiac function (both MRI and echocardiography) in terms of contractility [ejection fraction (%EF)] and left ventricular inner diameter (LVID) compared with the Dox-treated non-TG mice. However, both MHC-mut-hHsp27(S82A) and MHC-mut-hHsp27(S15A/S78A/S82A) mutants overexpressing TG mice did not show such a cardioprotection. Furthermore, transactivation of p53 was found to be attenuated only in Dox-treated MHC-hHsp27 mice-derived cardiomyocytes in vitro, as low p53 was detected in the nuclei, not in mutant hHsp27 overexpressing cardiomyocytes. Similarly, only in MHC-hHsp27 overexpressing cardiomyocytes, low Bax, higher mechanistic target of rapamycin (mTOR) phosphorylation, and low apoptotic poly(ADP-ribose) polymerase-1 (PARP-1) cleavage (89 kDa fragment) were detected. Pharmacological inhibition of p53 was more effective in mutant TG mice compared with MHC-hHsp27 mice. We conclude that phosphorylation of overexpressed Hsp27 at S82 and its association with p53 are essential for the cardioprotective effect of overexpressed Hsp27 against Dox-induced dilated cardiomyopathy. Only phosphorylated Hsp27 protects the heart by inhibiting p53 transactivation.NEW & NOTEWORTHY Requirement of serine phosphorylation in Hsp27 for cardioprotective effect against Dox is tested in various mutants overexpressing mice. Cardioprotective effect was found to be compromised in Hsp27 serine mutants overexpressed mice compared with wild-type overexpressing mice. These results indicate that cancer patients, who carry these mutations, may have higher risk of aggravated cardiomyopathy on treated with cardiotoxic chemotherapeutics such as doxorubicin.

Intestinal fatty acid-binding protein and osteoprotegerin in anthracycline-induced rabbit models of dilated cardiomyopathy.

Anthracyclines are used for chemotherapy in small animal cancer patients. However, cardiotoxic complications are very common with anthracycline use and induce multi-organ complications. The purpose of this study was to investigate the associations between multi-organ complications, focusing on the liver and intestine, and the serum concentrations of intestinal fatty acid-binding protein (I-FABP) and osteoprotegerin (OPG) in rabbits with daunorubicin-induced dilated cardiomyopathy (DCM). Sixteen New Zealand white male rabbits (16-20 weeks old), weighing 2.4-3.65 kg, were randomly divided into the control (n = 8) and daunorubicin-induced DCM (n = 8) groups. The concentration of serum I-FABP was significantly elevated in the DCM group (201.9 ± 16.6 pg/mL) compared to the control group (152.2 ± 19.9 g/mL). Additionally, the concentration of serum lactate was markedly increased in the DCM group (0.16 ± 0.01 mM) compared to that in the control group (0.02 ± 0.01 mmol/mL). In addition, the OPG concentration was significantly higher in the DCM group (2.44 ± 0.14 ng/mL) than in the control group (0.1 ± 0.08 ng/mL). Although the histopathology of the ileum did not significantly differ between groups, pathological changes were observed in the livers of the DCM group animals. In conclusion, multi-organ complications were recognized in DCM models and were accompanied by elevated serum I-FABP and OPG concentrations.

Early treatment with combination of SS31 and entresto effectively preserved the heart function in doxorubicin-induced dilated cardiomyopathic rat.

BACKGROUND: This study tested the hypothesis that early administration of SS31 and entresto (En) was superior to either one alone on preserving the heart function in setting of dilated cardiomyopathy (DCM) induced by doxorubicin (Dox) [accumulated dosage of 12.5 mg/kg/administered by intraperitoneal (IP) at 4 separated time points within 20 days] in rat. METHODS AND RESULTS: Adult-male SD rats (n = 40) were equally categorized into groups 1 (sham-control), 2 (DCM), 3 (DCM + SS31/0.7 mg/kg/day/IP, since day-14 after DCM induction to day-60), 4 [DCM + En (30 mg/kg/day/orally since day-14 after DCM induction to day-60)] and 5 (DCM + combined SS31-En), and animals were euthanized by day 60. By day 60, left-ventricular ejection-fraction (LVEF) was highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3 and 4 (all p < 0.0001), but it showed no difference between groups 3/4. The microscopic study showed that the fibrosis area/cardiomyocyte size and DNA-damaged (γ-H2AX+)/inflammatory (CD14+//CD68+) markers, and flow analysis of inflammatory (Ly6G+/MPO+/CD11b/c+) and early/late apoptosis (AN-V+/PI-//AN-V+/PI+) cells exhibited an opposite pattern of LVEF among the five groups (all p < 0.0001). The protein expressions of inflammatory upstream (TLR2/TLR4/MyD88/Mal/ TRAF6/IKK-α/IKK-ß) and downstream (p-NF-κb/TNF-α/IL-1ß/MMP-9), oxidative-stress/mitochondrial-damaged (NOX-1/NOX-2/cytosolic cytochrome-C/cyclophilin-D/DRP1) and autophagic/apoptotic (ratio of LC3B-II/LC3B-I and mitochondrial-Bax/caspase3/9) signaling pathways also exhibited an opposite pattern of LVEF among the five groups (all p < 0.0001). CONCLUSION: Combined SS31-En therapy was superior to either one alone on protecting the heart structural and functional integrities against Dox-induced DCM damage.

Concurrent Heavy Metal Exposures and Idiopathic Dilated Cardiomyopathy: A Case-Control Study from the Katanga Mining Area of the Democratic Republic of Congo.

Blood and/or urine levels of 27 heavy metals were determined by ICPMS in 41 patients with dilated cardiomyopathy (DCM) and 29 presumably healthy subjects from the Katanga Copperbelt (KC), in the Democratic Republic of Congo (DRC). After adjusting for age, gender, education level, and renal function, DCM probability was almost maximal for blood concentrations above 0.75 and 150 µg/dL for arsenic and copper, respectively. Urinary concentrations above 1 for chromium, 20 for copper, 600 for zinc, 30 for selenium, 2 for cadmium, 0.2 for antimony, 0.5 for thallium, and 0.05 for uranium, all in µg/g of creatinine, were also associated with increased DCM probability. Concurrent and multiple exposures to heavy metals, well beyond permissible levels, are associated with increased probability for DCM. Study findings warrant screening for metal toxicity in case of DCM and prompt public health measures to reduce exposures in the KC, DRC.

Drugs of Abuse and Heart Failure.

Substance use is common among those with heart failure (HF) and is associated with worse clinical outcomes. Alcohol, tobacco, cannabis, and cocaine are commonly abused substances that can contribute to the development and worsening of HF. Heavy alcohol consumption can lead to dilated cardiomyopathy, whereas moderate intake may decrease incident HF. Tobacco increases the risk of HF through coronary artery disease and coronary artery disease-independent mechanisms. Continued smoking worsens outcomes for those with HF and cessation is associated with an improved risk of major adverse cardiac events. Cannabis has complex interactions on the cardiovascular system depending on the method of consumption, amount consumed, and content of cannabinoids. Delta-9-tetrahydrocannabinol can increase sympathetic tone, cause vascular dysfunction, and may increase the risk of myocardial infarction. Cannabidiol is cardioprotective in preclinical studies and is a potential therapeutic target. Cocaine increases sympathetic tone and is a potent proarrhythmogenic agent. It increases the risk of myocardial infarction and can also lead to a dilated cardiomyopathy. The use of beta-blockers in those with HF and cocaine use is likely safe and effective. Future studies are needed to further elucidate the impact of these substances both on the development of HF and their effects on those who have HF.

Surgical ventricular restoration for rabbit dilated cardiomyopathy model: Preliminary study.

Dilated cardiomyopathy (DCM) is a common cardiovascular disease in dogs. It is primarily treated with beta-blockers. The aim of this preliminary study was to evaluate the efficacy of surgical ventricular restoration on daunorubicin-induced DCM in rabbits. The DCM model was generated in six rabbits by intravenous administration of daunorubicin (4 mg/kg/week) for 6 weeks. Echocardiography was performed before and after left ventricular (LV) reconstruction surgery to evaluate the LV function. The surgery was performed using non-absorbent prosthetic sheets and 5-0 polypropylene sutures, between the left anterior descending branch and the circumflex branch of the left coronary artery. We measured LV function 3 weeks postoperatively and collected the hearts for histopathological examination. We observed significant improvements in the LV internal dimension volume at both end-diastole and end-systole compared to the preoperative values. Fraction shortening showed a substantial improvement from 23.8 ± 1.4% to 30.9 ± 1.3%. In addition, the ejection fraction increased from 35.3% to 51.9%. On histological examination, the left ventricular wall was markedly thin. Furthermore, we observed fibrosis between the myocardial cells around the sutured site. The LV volume and LV functions significantly improved postoperatively. However, further investigation is required to determine the long-term effects of surgical ventricular restoration.

Gemcitabine-induced dilated-cardiomyopathy in patient with platinum-refractory ovarian-cancer: A case report and literature review.

INTRODUCTION: Gemcitabine is a nucleoside analog and pyrimidine antimetabolite that inhibits RNA synthesis, currently approved for use to treat a variety of cancers, among which ovarian cancers. Gemcitabine is considered relatively safe and it is generally well tolerated, with rarely reported cardiac side effects. CASE REPORT: We report a case of gemcitabine induced dilated cardiomyopathy in a 41-year-old woman receiving gemcitabine as second line treatment for platinum-resistant ovarian cancer without pre-existing hypertension or significant cardiac history.Management and Outcome: The patient presented with clinical symptoms and laboratory and imaging results suggestive of congestive cardiac failure, with a left ventricular ejection fraction of 15%. Gemcitabine administration was stopped and Furosemide with ACE-inhibitors and Beta-blocker agents were initiated. At that point the clinical situation improved: symptoms and findings disappeared with gemcitabine cessation. DISCUSSION: Our case demonstrated for the first time objective evidence for dilated cardiomyopathy induced by gemcitabine in a young patient with platinum-resistant ovarian cancer without pre-existing significant cardiac history. Although rare, gemcitabine-induced cardiotoxicity should be promptly recognized in order to take appropriate measures to manage it.

Epinephrine soaked tampons induced transient acute dilated cardiomyopathy during FESS procedure.

BACKGROUND: Epinephrine, in all modes of use, may pose a wide range of cardiotoxic events, ranging from sinus tachycardia to heart failure, life threatening arrhythmias, and even death. Because of daily and extensive use of epinephrine, these unusual and rare events tend to be forgotten by physicians. We present a case of dilated cardiomyopathy that developed following routine use of epinephrine-impregnated tampons during function endoscopic sinus (FESS) surgery. CASE PRESENTATION: A healthy, 24-year-old man with no family history of heart disease has undergone elective surgery under general anesthesia to repair the paranasal sinuses using endoscopic approach. During surgery, soon after being treated with 1: 1000 diluted epinephrine-soaked tampons, an hypertensive crisis was noticed followed by pulseless electrical activity. An extensive examination led to the diagnosis of non-ischemic dilated cardiomyopathy. After several days of heart failure medical therapy, complete resolution of all structural and functional changes was achieved. CONCLUSION: In our case, we present an unusual and rare event of acute dilated cardiomyopathy following the use of epinephrine-soaked tampons during elective FESS surgery. A prompt response was observed after several days of heart failure treatment. Awareness of the epinephrine cardiotoxic potential even in the form of soaked tampons is essential for proper diagnosis and prompt treatment.

Dilated Cardiomyopathy in an Adult Renal Transplant Recipient: Recovery Upon Tacrolimus to Sirolimus Switch: A Case Report.

The objective of immunosuppressive drugs used in solid organ transplantation is to achieve acceptable rejection rates, minimize infections, and prolong graft and patient survival. Cardiovascular disease is a major cause of death in kidney transplant recipients. The drugs commonly used to prevent rejection (calcineurin inhibitors [CNIs] and steroids) contribute to cardiac disease seen in transplant patients by increasing the risk of hypertension and diabetes. Direct cardiac toxicity of chemotherapeutic drugs such as doxorubicin is well-known but potential direct effect of CNIs on myocardium is less explored and understood. Cardiac toxicity a rare but serious adverse effect of tacrolimus, has been observed in patients receiving solid organ transplants such as liver, bowel and kidney. In this report, we describe a case of new onset severe dilated cardiomyopathy after kidney transplantation. Reversal of heart failure occurred after tacrolimus discontinuation and the switch to a mammalian target of rapamycin (mTOR) inhibitor: sirolimus.