Advancing physiological maturation in human induced pluripotent stem cell-derived cardiac muscle by gene editing an inducible adult troponin isoform switch.

Advancing maturation of stem cell-derived cardiac muscle represents a major barrier to progress in cardiac regenerative medicine. Cardiac muscle maturation involves a myriad of gene, protein, and cell-based transitions, spanning across all aspects of cardiac muscle form and function. We focused here on a key developmentally controlled transition in the cardiac sarcomere, the functional unit of the heart. Using a gene-editing platform, human induced pluripotent stem cell (hiPSCs) were engineered with a drug-inducible expression cassette driving the adult cardiac troponin I (cTnI) regulatory isoform, a transition shown to be a rate-limiting step in advancing sarcomeric maturation of hiPSC cardiac muscle (hiPSC-CM) toward the adult state. Findings show that induction of the adult cTnI isoform resulted in the physiological acquisition of adult-like cardiac contractile function in hiPSC-CMs in vitro. Specifically, cTnI induction accelerated relaxation kinetics at baseline conditions, a result independent of alterations in the kinetics of the intracellular Ca2+ transient. In comparison, isogenic unedited hiPSC-CMs had no cTnI induction and no change in relaxation function. Temporal control of adult cTnI isoform induction did not alter other developmentally regulated sarcomere transitions, including myosin heavy chain isoform expression, nor did it affect expression of SERCA2a or phospholamban. Taken together, precision genetic targeting of sarcomere maturation via inducible TnI isoform switching enables physiologically relevant adult myocardium-like contractile adaptations that are essential for beat-to-beat modulation of adult human heart performance. These findings have relevance to hiPSC-CM structure-function and drug-discovery studies in vitro, as well as for potential future clinical applications of physiologically optimized hiPSC-CM in cardiac regeneration/repair.

Comparing the Effects of Gamification and Teach-Back Training Methods on Adherence to a Therapeutic Regimen in Patients After Coronary Artery Bypass Graft Surgery: Randomized Clinical Trial.

BACKGROUND: Patients undergoing coronary artery bypass graft surgery (CABGS) may fail to adhere to their treatment regimen for many reasons. Among these, one of the most important reasons for nonadherence is the inadequate training of such patients or training using inappropriate methods. OBJECTIVE: This study aimed to compare the effect of gamification and teach-back training methods on adherence to a therapeutic regimen in patients after CABGS. METHODS: This randomized clinical trial was conducted on 123 patients undergoing CABGS in Tehran, Iran, in 2019. Training was provided to the teach-back group individually. In the gamification group, an app developed for the purpose was installed on each patient's smartphone, with training given via this device. The control group received usual care, or routine training. Adherence to the therapeutic regimen was assessed using a questionnaire on adherence to a therapeutic regimen (physical activity and dietary regimen) and an adherence scale as a pretest and a 1-month posttest. RESULTS: One-way analysis of variance (ANOVA) for comparing the mean scores of teach-back and gamification training methods showed that the mean normalized scores for the dietary regimen (P<.001, F=71.80), movement regimen (P<.001, F=124.53), and medication regimen (P<.001, F=9.66) before and after intervention were significantly different between the teach-back, gamification, and control groups. In addition, the results of the Dunnett test showed that the teach-back and gamification groups were significantly different from the control group in all three treatment regimen methods. There was no statistically significant difference in adherence to the therapeutic regimen between the teach-back and control groups. CONCLUSIONS: Based on the results of this study, the use of teach-back and gamification training approaches may be suggested for patients after CABGS to facilitate adherence to the therapeutic regimen. TRIAL REGISTRATION: Iranian Registry of Clinical Trials IRCT20111203008286N8; https://en.irct.ir/trial/41507.

Multi-Imaging Method to Assay the Contractile Mechanical Output of Micropatterned Human iPSC-Derived Cardiac Myocytes.

RATIONALE: During each beat, cardiac myocytes (CMs) generate the mechanical output necessary for heart function through contractile mechanisms that involve shortening of sarcomeres along myofibrils. Human-induced pluripotent stem cells (hiPSCs) can be differentiated into CMs (hiPSC-CMs) that model cardiac contractile mechanical output more robustly when micropatterned into physiological shapes. Quantifying the mechanical output of these cells enables us to assay cardiac activity in a dish. OBJECTIVE: We sought to develop a computational platform that integrates analytic approaches to quantify the mechanical output of single micropatterned hiPSC-CMs from microscopy videos. METHODS AND RESULTS: We micropatterned single hiPSC-CMs on deformable polyacrylamide substrates containing fluorescent microbeads. We acquired videos of single beating cells, of microbead displacement during contractions, and of fluorescently labeled myofibrils. These videos were independently analyzed to obtain parameters that capture the mechanical output of the imaged single cells. We also developed novel methods to quantify sarcomere length from videos of moving myofibrils and to analyze loss of synchronicity of beating in cells with contractile defects. We tested this computational platform by detecting variations in mechanical output induced by drugs and in cells expressing low levels of myosin-binding protein C. CONCLUSIONS: Our method can measure the cardiac function of single micropatterned hiPSC-CMs and determine contractile parameters that can be used to elucidate mechanisms that underlie variations in CM function. This platform will be amenable to future studies of the effects of mutations and drugs on cardiac function.

Mitral valve-in-valve replacement supported by a transapically snared guidewire via septostomy.

We describe a 72-year-old woman, a known case of rheumatic heart disease with a history of mitral and aortic valve replacement 8 years previously, who underwent mitral valve-in-valve replacement supported by a transapically snared guidewire through septostomy.

Single-session double valve replacement: TAVI+tricuspid valve-in-valve procedures.

We describe a 70-year-old lady with rheumatic heart disease and a history of the mitral valve and tricuspid valve replacement, who underwent transcatheter aortic valve implantation and the tricuspid valve-in-valve procedure in a single session.

Smoking and wound complications after coronary artery bypass grafting.

BACKGROUND: The harmful effects of smoking on the postsurgical wound healing disturbances have been widely investigated across various surgical procedures. These effects after coronary artery bypass graft (CABG) surgery have been less explored. We aimed to investigate the association of smoking and the wound healing problems in post-CABG patients. MATERIALS AND METHODS: We compared the incidence of wound complications in 405 smokers and 405 nonsmokers who underwent an elective CABG surgery. The incidence of leg and sternal wound complications was evaluated during the first 7 d as well as at a 6-wk postoperative visit. RESULTS: One hundred fifty-six leg wound complications were noted in 132 patients (16.3%). The overall rate of leg wound healing disturbances was significantly higher in smokers than those in nonsmokers (odds ratio, 1.47; 95% confidence interval, 1.109-4.019; P = 0.010). The incidence rates of leg wound edge necrosis and dehiscence were significantly higher in smokers compared with those in nonsmokers (3.7% versus 0.7%, P = 0.004 and 6.6% versus 0.7%, P < 0.0001, respectively). We found no significant differences between the incidence of postoperative leg wound infection, hematoma, wound edema, and seroma in active smokers and those who never smoked. Thirty-seven postsurgical sternal wound complications (4.6%) were developed in 33 patients (4.1%). The overall rate of sternal wound healing disturbances was similar between smokers and nonsmokers. There was a trend between the sternal wound dehiscence and smoking (P = 0.03); however, the other sternal wound complications were not associated with smoking. CONCLUSIONS: Smoking may contribute to the disturbances of wound healing, especially wound dehiscence, in post-CABG patients.

Aortic root replacement using a modified composite valve graft.

OBJECTIVES: We used a modified technique of a composite graft by moving the valve prosthesis away from the end into the inside of the tube and compared the effectiveness of this surgical method with the standard valved conduits. METHODS: Through a prospective nonrandomized clinical study between March 2011 and June 2012, we performed replacement of the aortic valve and ascending aorta in 30 consecutive patients using a valved composite graft with a mechanical valve prosthesis. A modified self-assembled valved composite graft was employed in 20 patients (Modified group), while the remaining 10 patients received the standard composite graft (Control group). RESULTS: There was significantly less bleeding in the patients with modified grafts (184 vs. 415 mL, p < 0.05). Moreover, the mean transvalvular gradient of the composite graft patients was lower in the modified group than in the control group (9 vs. 14 mmHg, respectively, p < 0.05). CONCLUSIONS: The modified valve composite graft technique results in good hemodynamics and appears to limit blood loss.

Technetium-99m-ubiquicidin scintigraphy in the detection of infective endocarditis.

We present a case of infective endocarditis (IE) diagnosed by the increased (99m)Tc-UBI specific uptake in the tricuspid valve region. In conclusion, our case data may indicate a first pass-like distribution with strong avidity of the tracer to infective endocarditis, facilitating image interpretation.

A fatal case of fulminant myocarditis after influenza infection with a rapidly progressive course: A case report.

Myocarditis is an inflammation of the heart muscle. The most common cause of myocarditis is viral infections. clinical presentation of acute myocarditis is highly variable and varies from asymptomatic to fulminant heart failure or sudden death. Fulminant myocarditis is a severe form of myocarditis characterized by heart failure, arrhythmia, cardiogenic shock, and sudden cardiac arrest. Early diagnosis and proper treatment are essential for improved survival. We present a case of a 34-year-old woman who presented with viral symptoms for two days and then died suddenly.

Targeting HDAC6 to treat heart failure with preserved ejection fraction in mice.

Heart failure with preserved ejection fraction (HFpEF) poses therapeutic challenges due to the limited treatment options. Building upon our previous research that demonstrates the efficacy of histone deacetylase 6 (HDAC6) inhibition in a genetic cardiomyopathy model, we investigate HDAC6's role in HFpEF due to their shared mechanisms of inflammation and metabolism. Here, we show that inhibiting HDAC6 with TYA-018 effectively reverses established heart failure and its associated symptoms in male HFpEF mouse models. Additionally, in male mice lacking Hdac6 gene, HFpEF progression is delayed and they are resistant to TYA-018's effects. The efficacy of TYA-018 is comparable to a sodium-glucose cotransporter 2 (SGLT2) inhibitor, and the combination shows enhanced effects. Mechanistically, TYA-018 restores gene expression related to hypertrophy, fibrosis, and mitochondrial energy production in HFpEF heart tissues. Furthermore, TYA-018 also inhibits activation of human cardiac fibroblasts and enhances mitochondrial respiratory capacity in cardiomyocytes. In this work, our findings show that HDAC6 impacts on heart pathophysiology and is a promising target for HFpEF treatment.

Functional human artificial chromosomes are generated and stably maintained in human embryonic stem cells.

We present a novel and efficient non-integrating gene expression system in human embryonic stem cells (hESc) utilizing human artificial chromosomes (HAC), which behave as autonomous endogenous host chromosomes and segregate correctly during cell division. HAC are important vectors for investigating the organization and structure of the kinetochore, and gene complementation. HAC have so far been obtained in immortalized or tumour-derived cell lines, but never in stem cells, thus limiting their potential therapeutic application. In this work, we modified the herpes simplex virus type 1 amplicon system for efficient transfer of HAC DNA into two hESc. The deriving stable clones generated green fluorescent protein gene-expressing HAC at high frequency, which were stably maintained without selection for 3 months. Importantly, no integration of the HAC DNA was observed in the hESc lines, compared with the fibrosarcoma-derived control cells, where the exogenous DNA frequently integrated in the host genome. The hESc retained pluripotency, differentiation and teratoma formation capabilities. This is the first report of successfully generating gene expressing de novo HAC in hESc, and is a significant step towards the genetic manipulation of stem cells and potential therapeutic applications.

Efficacy of papillary muscle approximation in preventing functional mitral regurgitation recurrence in high-risk patients with ischaemic cardiomyopathy and mitral regurgitation.

BACKGROUND: Dilated cardiomyopathy (DCM) is often complicated by the appearance of functional mitral regurgitation (FMR). Although mitral ring annuloplasty (MAP) is the most widely used surgical procedure for the surgical treatment of FMR, there are still reports of patients who suffer recurrent FMR at later follow-ups. We sought to investigate the efficacy of papillary muscle approximation (PMA) combined with MAP in preventing the recurrence of FMR in high-risk patients. METHODS: One hundred patients with ischaemic (74%) or non-ischaemic (26%) DCM along with severe (4+/4+) or moderately severe (3+/4+) FMR were enrolled in this prospective, cross-sectional study. According to the interpapillary muscle distance (iPMD) and coaptation depth (CD), the patients were risk stratified as low (iPMD + CD 30 mm, n= 69) and high-risk (iPMD + CD > 30 mm, n= 31) groups. The low-risk patients underwent only MAP, whereas the high-risk patients underwent MAP plus PMA. RESULTS: After a mean +/- SD follow-up of 40.8 +/- 12.5 months, recurrence of 3+ to 4+ MR was observed in 8 (8.7%) and 7 (11.1%) patients in the annuloplasty group (MAP-only) and one (3.4%) patient in the combination group (MAP plus PMA) (P= 0.428). At the final follow-up, the New York Heart Association (NYHA) function class was 1.57 +/- 0.62 in the annuloplasty group and 1.45 +/- 0.57 in the combination group; there was no significant difference in NYHA function class between the first and final follow-ups (P> 0.05). CONCLUSION: iPMD is a valuable index in the riskstratification of the recurrence of post-MAP MR in patients with DCM complicated by FMR.The patients treated with MAP plus PMA had more favourable outcomes and lower recurrence rates than those treated via the traditional route of MAP only.

Functional analysis of a common BAG3 allele associated with protection from heart failure.

Multiple genetic association studies have correlated a common allelic block linked to the BAG3 gene with a decreased incidence of heart failure, but the molecular mechanism remains elusive. In this study, we used induced pluripotent stem cells to test if the only coding variant in this allele block, BAG3C151R, alters protein and cellular function in human cardiomyocytes. Quantitative protein interaction analysis identified changes in BAG3C151R protein partners specific to cardiomyocytes. Knockdown of genes encoding for BAG3-interacting factors in cardiomyocytes followed by myofibrillar analysis revealed that BAG3C151R associates more strongly with proteins involved in the maintenance of myofibrillar integrity. Finally, we demonstrate that cardiomyocytes expressing the BAG3C151R variant have improved response to proteotoxic stress in a dose-dependent manner. This study suggests that BAG3C151R could be responsible for the cardioprotective effect of the haplotype block, by increasing cardiomyocyte protection from stress. Preferential binding partners of BAG3C151R may reveal potential targets for cardioprotective therapies.

Surgical Repair of a Giant Right Atrium Aneurysm That was Incidentally Found in a Boy.

Giant right atrial aneurysms are rare defects with different clinical presentations ranging from lack of symptoms to heart failure. They are diagnosed based on incidental findings. It is commonly found when echocardiography or chest X-ray is performed. Concurrent congenital heart disease and large atrial size are risk factors that may increase the risks of complications such as thromboembolism, fatal arrhythmias, aneurysm rupture, and sudden death. The best treatment has been controversial, with some patients managed surgically and others conservatively. We present a case of a giant right atrium aneurysm that was incidentally detected during a routine examination. The patient underwent successful surgical resection of the right atrial aneurysm.

A Very Rare Case of Isolated Spontaneous Pneumopericardium Secondary to COVID-19.

Coronavirus disease 2019(COVID-19) is currently a pandemic. In addition to respiratory symptoms, involvement of other organs such as the pericardium is also seen. Pneumomediastinum in COVID-19 patients has rarely been reported. Isolated pneumopericardium without pneumomediastinum is even more uncommon. We described a case of COVID-19 in association with pneumopericardium. To the best of our knowledge, no case with isolated pneumopericardium has been reported thus far.

Incidentally Detected Asymptomatic Cardiac Myxoma in a Patient With COVID-19.

Primary cardiac tumors, such as myxomas, are rare. About 75% of myxomas occur in the left atrium of the heart. Myxomas can have a broad clinical spectrum. The clinical presentation varies from asymptomatic to sudden cardiac death. Sometimes, a diagnosis is difficult. Cardiac myxoma can cause hemodynamic disturbances in the setting of pneumonia and hypercoagulable state in patients with Coronavirus disease 2019(COVID-19) and make treatment decisions difficult. We present a case of unusually huge left atrial mass discovered incidentally in a patient with COVID-19. Upon workup, an echocardiogram revealed an incidental 7 × 5 cm left atrial myxoma. Preoperatively, the patient was monitored closely in the ICU. After stabilization in the ICU, the patient was taken to surgery and the tumor was successfully removed. Pathohistological results after surgical removal of the tumor confirmed the diagnosis of cardiac myxoma. We consider our case extremely rare due to the asymptomatic course despite the large size of the tumor.

Type B Interrupted Aortic Arch With a Very Large Right Subclavian Artery Aneurysm in an Adult.

Interruption of the aortic arch and right subclavian artery aneurysm is a rare congenital malformation. Survival in adults depends on the formation of collaterals to supply the descending aorta. The interruption of the aortic arch must be taken into account, particularly in patients with hypertension and weak pulses in the lower extremities. We present a case of aortic arch interruption and a right subclavian artery aneurysm in a woman who survived to adulthood.

Phenotypic screening with deep learning identifies HDAC6 inhibitors as cardioprotective in a BAG3 mouse model of dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is characterized by reduced cardiac output, as well as thinning and enlargement of left ventricular chambers. These characteristics eventually lead to heart failure. Current standards of care do not target the underlying molecular mechanisms associated with genetic forms of heart failure, driving a need to develop novel therapeutics for DCM. To identify candidate therapeutics, we developed an in vitro DCM model using induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) deficient in B-cell lymphoma 2 (BCL2)-associated athanogene 3 (BAG3). With these BAG3-deficient iPSC-CMs, we identified cardioprotective drugs using a phenotypic screen and deep learning. From a library of 5500 bioactive compounds and siRNA validation, we found that inhibiting histone deacetylase 6 (HDAC6) was cardioprotective at the sarcomere level. We translated this finding to a BAG3 cardiomyocyte-knockout (BAG3cKO) mouse model of DCM, showing that inhibiting HDAC6 with two isoform-selective inhibitors (tubastatin A and a novel inhibitor TYA-018) protected heart function. In BAG3cKO and BAG3E455K mice, HDAC6 inhibitors improved left ventricular ejection fraction and reduced left ventricular diameter at diastole and systole. In BAG3cKO mice, TYA-018 protected against sarcomere damage and reduced Nppb expression. Based on integrated transcriptomics and proteomics and mitochondrial function analysis, TYA-018 also enhanced energetics in these mice by increasing expression of targets associated with fatty acid metabolism, protein metabolism, and oxidative phosphorylation. Our results demonstrate the power of combining iPSC-CMs with phenotypic screening and deep learning to accelerate drug discovery, and they support developing novel therapies that address underlying mechanisms associated with heart disease.

The interval between Ins2 and Ascl2 is dispensable for imprinting centre function in the murine Beckwith-Wiedemann region.

Imprinted genes are commonly clustered in domains across the mammalian genome, suggesting a degree of coregulation via long-range coordination of their monoallelic transcription. The distal end of mouse chromosome 7 (Chr 7) contains two clusters of imprinted genes within a approximately 1 Mb domain. This region is conserved on human 11p15.5 where it is implicated in the Beckwith-Wiedemann syndrome. In both species, imprinted regulation requires two critical cis-acting imprinting centres, carrying different germline epigenetic marks and mediating imprinted expression in the proximal and distal sub-domains. The clusters are separated by a region containing the gene for tyrosine hydroxylase (Th) as well as a high density of short repeats and retrotransposons in the mouse. We have used the Cre-loxP recombination system in vivo to engineer an interstitial deletion of this approximately 280-kb intervening region previously proposed to participate in the imprinting mechanism or to act as a boundary between the two sub-domains. The deletion allele, Del(7AI), is silent with respect to epigenetic marking at the two flanking imprinting centres. Reciprocal inheritance of Del(7AI) demonstrates that the deleted region, which represents more than a quarter of the previously defined imprinted domain, is associated with intrauterine growth restriction in maternal heterozygotes. In homozygotes, the deficiency behaves as a Th null allele and can be rescued pharmacologically by bypassing the metabolic requirement for TH in utero. Our results show that the deleted interval is not required for normal imprinting on distal Chr 7 and uncover a new imprinted growth phenotype.

Huge Hydatid Cyst of the Right Ventricular Outflow Tract.

Hydatid disease is a common health problem in sheep-farming countries such as Iran. The liver and lungs are the most common primary sites of hydatid cysts in humans. Cardiac involvement is an uncommon manifestation, and the right ventricle outflow tract (RVOT) is rarely involved. This is a case report of a 34-year-old man who presented to the Heart Clinic, Tehran, Iran, in 2019 with a history of dyspnoea and fatigue. Following an imaging study, the patient was diagnosed with an RVOT hydatid cyst. He underwent surgical resection of the cyst. The post-operative course was uneventful.