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Developing technologies for efficient and scalable disruption of gene expression will provide powerful tools for studying gene function, developmental pathways, and disease mechanisms. Here, we develop clustered regularly interspaced short palindromic repeat interference (CRISPRi) to repress gene expression in human induced pluripotent stem cells (iPSCs). CRISPRi, in which a doxycycline-inducible deactivated Cas9 is fused to a KRAB repression domain, can specifically and reversibly inhibit gene expression in iPSCs and iPSC-derived cardiac progenitors, cardiomyocytes, and T lymphocytes. This gene repression system is tunable and has the potential to silence single alleles. Compared with CRISPR nuclease (CRISPRn), CRISPRi gene repression is more efficient and homogenous across cell populations. The CRISPRi system in iPSCs provides a powerful platform to perform genome-scale screens in a wide range of iPSC-derived cell types, dissect developmental pathways, and model disease.

Cardiac and hepatic toxicity result from induced disruption of the functioning of cardiomyocytes and hepatocytes, respectively, which is tightly related to the organization of their subcellular structures. Cellular structure can be analyzed from microscopy imaging data. However, subtle or complex structural changes that are not easily perceived may be missed by conventional image-analysis techniques. Here we report the evaluation of PhenoTox, an image-based deep-learning method of quantifying drug-induced structural changes using human hepatocytes and cardiomyocytes derived from human induced pluripotent stem cells. We assessed the ability of the deep learning method to detect variations in the organization of cellular structures from images of fixed or live cells. We also evaluated the power and sensitivity of the method for detecting toxic effects of drugs by conducting a set of experiments using known toxicants and other methods of screening for cytotoxic effects. Moreover, we used PhenoTox to characterize the effects of tamoxifen and doxorubicin-which cause liver toxicity-on hepatocytes. PhenoTox revealed differences related to loss of cytochrome P450 3A4 activity, for which it showed greater sensitivity than a caspase 3/7 assay. Finally, PhenoTox detected structural toxicity in cardiomyocytes, which was correlated with contractility defects induced by doxorubicin, erlotinib, and sorafenib. Taken together, the results demonstrated that PhenoTox can capture the subtle morphological changes that are early signs of toxicity in both hepatocytes and cardiomyocytes.

Tracheoesophageal disorders and diseases are prevalent in humans such that an organoid model of human esophagus could be greatly beneficial. We therefore established a three-dimensional esophageal organoid culture system through the directed differentiation of human pluripotent stem cells (hPSCs). We identified that sequential manipulation of several signaling pathways was needed to first pattern definitive endoderm into foregut, then into anterior foregut (AFG), then dorsal AFG spheroids (dAFG). Outgrowth of dAFG spheroids for 1-2 months resulted in human esophageal organoids (HEOs) with a stratified squamous epithelium comparable to a late gestation mouse embryonic esophagus. We then used HEOs and mouse embryos to identify how SOX2 mediates separation of the esophageal and respiratory lineages and found that loss of endodermal Sox2 results in complete esophageal agenesis. At the transcriptional level, SOX2 acts to promote esophageal specification in both mice and humans in part by inhibiting Wnt signaling in the dorsal AFG and promoting survival of esophageal epithelium. In addition to this use of hPSC-derived esophageal organoids to study development, HEOs can be used for future studies of esophageal pathologies, such as Barrett’s metaplasia and carcinoma.

Background The ideal management of ischemic mitral regurgitation (MR) remains a clinical dilemma because of the suboptimal available therapeutic options. Recently, new concepts have emerged, pointing to the benefits of a patient selection approach when debating the management of moderate ischemic MR. We investigated the predictability of low-dose dobutamine stress echocardiography (DSE) in selecting candidates for CABG with moderate MR for valve repair. Methods From November 2002 to May 2010, 110 candidates for first-time CABG, who were admitted to the cardiac surgery department in Day General Hospital (Tehran, Iran), were enrolled in the present cross-sectional study. DSE was performed for each case before CABG. Those with positive findings underwent CABG alone and those with negative results underwent concomitant CABG and mitral valve repair. The patients were followed up for a minimum of 60 months. Results Of the 110 patients, 47 (42.72%) had positive test results and underwent CABG alone and 63 (57.28%) had negative DSE results and underwent concomitant CABG and mitral valve repair. The MR degree had decreased from 2.8 ± 0.3 preoperatively to 1.46 ± 0.6 early during the hospital stay and 1.9 ± 0.7 during late follow-up in the CABG group. It had decreased from 2.84 ± 0.4 preoperatively to 0.93 ± 0.65 postoperatively but then increased to 1.41 ± 0.9 during late follow-up, for a significant decrease in the combined group ( P Conclusions Despite its utility in selecting CABG patients with moderate ischemic MR for valve repair from a short-term perspective, the use of DSE cannot predict the long-term outcomes of these patients.

Background: Patient's illness perception is formed base on Patient's beliefs and perceived information about their conditions and it may influence the individual's mental health and how the patients deal with the medical conditions. The aim of this study was to determine the relationship between illness perception and quality of life in patients with coronary artery bypass graft (CABG). Methods: For this purpose, 82 patients (51 men and 31 women) who underwent CABG from October 2010 to May 2011 in four different hospitals in Tehran were selected as sample. The patients were evaluated with the brief illness perception questionnaire (Brief IPQ) and after three months follow up were assessed with 36-item Short-Form quality of life questionnaire (SF-36). Data was analyzed by Pearson correlation and multiple variable regression models. Findings: A relationship between illness perception and quality of life in patients with CABG was observed (r=0.445, p

Congenital aneurysmal dilatation of the left atrium is a rare anomaly that could be associated with supraventricular arrhythmias and life-threatening systemic embolization. We describe a 32-year-old man with a giant left atrial aneurysm diagnosed with new imaging modalities that underwent surgical resection with good results. Learning objective: Left atrial aneurysms are rare and characterized by their origin from an otherwise normal atrium, a clearly defined communication with the atrial cavity, and their intrapericardial location. Because of associated complications, early diagnosis and surgical excision are mandatory even in asymptomatic, otherwise healthy patients. The evaluations with cardiac imaging techniques should be considered in any patient with an unexplained abnormality on the chest radiograph or initial echocardiography.>

The aim of this study was to investigate the feasibility of performing papillary muscle repositioning (PMR) for subvalvular-sparing mitral valve replacement procedures in patients with ischemic mitral regurgitation and to determine the early and late effects of this procedure on the clinical outcome and left ventricular mechanics.We prospectively randomly allocated 50 patients with severe ischemic mitral regurgitation and left ventricle dysfunction who were candidates for coronary artery bypass graft surgery and mitral valve replacement into a total chordal-sparing mitral valve replacement group or a PMR group. Echocardiography was performed preoperatively, at discharge, and after 3 years to determine the left ventricular dimensions, shape, and function.The reduction in the left ventricle volumes and sphericity index in the PMR group was more significant than that in the other group. With regard to the left ventricular end-systolic and left ventricular end-diastolic volumes, sphericity index, and ejection fraction, the PMR group showed better results (p0.05), but the difference in New York Heart Association functional class after 3 years was not statistically significant between the two groups (p0.05).The PMR technique described herein can dramatically help ischemic patients by affecting the left ventricular shape and function more efficiently compared with the complete retention of the mitral subvalvular apparatus if the mitral valve is to be replaced.

ObjectiveIn patients with ischemic cardiomyopathy and substantial amounts of dysfunctional but viable myocardium, revascularization cannot always improve the left ventricular ejection fraction. We sought to investigate the interaction between the left ventricular volume and the amount of viable myocardium to predict the left ventricular ejection fraction increase after revascularization.MethodsEighty-five consecutive patients with a depressed left ventricular ejection fraction (mean: 27.3% ± 5.2%) underwent coronary artery bypass grafting after a dobutamine stress echocardiography had determined that they had at least 4 viable segments. Six months after coronary artery bypass grafting, left ventricular ejection fraction and regional wall motion were reassessed.ResultsAlthough the left ventricular ejection fraction was expected to recover more than 5% in all 85 patients after coronary artery bypass grafting, it did not improve in 15 patients (17.6%) despite the presence of viable segments. The likelihood of the left ventricular ejection fraction recovery decreased proportionally with an increase in the left ventricular end-systolic volume. The nonimprovers had a higher left ventricular end-systolic volume (164.2 ± 22.4 mL vs 125.6 ± 23.4 mL, P = .0001). In addition, the number of viable segments during the dobutamine stress echocardiography had a significant correlation with the ejection fraction increase after 6 months (P < .0001). Patients with 6 viable segments showed a good outcome irrespective of their left ventricular end-systolic volume. In patients with fewer than 6 viable segments, left ventricular end-systolic volume was a major factor in the prognosis: Patients with left ventricular end-systolic volume of 145 or more had a poor left ventricular ejection fraction increase and vice versa.ConclusionThe extent of left ventricular remodeling determines the rate of functional improvement after coronary artery bypass grafting. Patients with a high left ventricular end-systolic volume and fewer than 6 viable segments have a lower likelihood of improvement.

Background Ischemic mitral regurgitation (IMR) is a complex lesion to repair, and its successful management requires an understanding of its mechanism and severity. Ring annuloplasty, currently the surgical treatment of choice for IMR, has failure rates as high as 30% in patients with functional IMR. We sought to study the variables that can predict IMR recurrence after ring annuloplasty. Methods This is a prospective study of 114 patients with 3+ to 4+ IMR who underwent coronary artery bypass grafting and mitral valve annuloplasty with acceptable results at an approximately 2-year follow-up. Variables were compared in a failure group, comprising patients with 2+ or higher MR and a nonfailure group, consisting of those with less than +2 MR. Results There were five postoperative in-hospital deaths. During follow-up, 14 patients died and 95 patients were evaluated. After a mean follow-up of 22.2 ± 4.6 months for the nonfailure group and 18.6 ± 5.6 months for the failure group, 23 patients (24.4%) exhibited annuloplasty failure. Some variables had an effect in our univariate analysis, but only interpapillary muscle distance had a relationship with recurrent MR in the multivariate analysis. Mean preoperative interpapillary muscle distance was 15.0 ± 4.0 and 26.5 ± 2.9 in the nonfailure group and failure group, respectively ( p Conclusions Interpapillary muscle distance, as a reliable index of dysfunctional subvalvular apparatus in patients with IMR, can predict late postrepair MR and indicate the need for a procedure complementary to annuloplasty.

Background The aim of this study was to investigate the feasibility of performing papillary muscle repositioning for mitral valve replacement procedures in patients with left ventricular dysfunction and to determine the early and late effects of this procedure on clinical outcome and left ventricular mechanics. Methods One hundred patients with ejection fraction less than 40, who were candidates for isolated surgical correction of mitral insufficiency, had mitral valve replacement and were prospectively randomly assigned to either total chordal-sparing or papillary muscle repositioning. Fifty subjects underwent papillary muscle repositioning (PMR group), and the remaining 50 had complete preservation of all chordal structures with mitral valve replacement (CMVR group). Echocardiography was performed preoperatively, at discharge, and after 2 years to determine dimensions, left ventricular shape, and function. Results End-diastolic and -systolic volumes decreased in both groups initially and continued to decline. Decreasing volumes, however, were more significant in the PMR group, in which the significant decrease in the sphericity index continued for another 2 years. In contrast, the sphericity index in the CMVR group had no significant changes at discharge and at 2 years. In terms of systolic performance, ejection fraction had no significant changes in the CMVR group, whereas ejection fraction significantly increased in the PMR group. Conclusions Papillary muscle repositioning may result in more favorable left ventricular remodeling compared with complete retention of the mitral subvalvular apparatus during mitral valve replacement. It confers a significant early and late advantage by causing significant reductions in the left ventricular chamber volume, sphericity index, and systolic performance.

We present a practical and accurate way to measure artificial chordae length in mitral valve repair. During preoperative transesophageal echocardiography, the distance between the head of the posterior papillary muscle and the mitral annulus plane at the coaptation of the leaflets is measured; this is the length of the new chorda. Every millimeter of braided 4-0 Gore-Tex (W.L. Gore & Assoc, Flagstaff, AZ) contains two tight reverse knots; therefore, the number of the knots determines the accurate length of the artificial chorda.

A 53-year-old woman presented to our center with progressive fatigue and dyspnea on exertion (New York Heart Association functional class III). The patient's medical history was significant for multiple cardiac interventions: open mitral commissurotomy for the treatment of rheumatic mitral stenosis

A 30-year-old man was kicked in the chest during a fight and developed chest pain. He presented to the hospital the same day, but it was thought that the pain was due to a broken rib and he was discharged with nonsteroidal antiinflammatory drugs. The pain was intermittent and continued; after three days he was referred to our hospital for a possible cardiac source of the pain. An electrocardiogram showed extensive anteroseptal myocardial infarction, and ST segment was elevated in leads V1 to V6. Cardiac enzymes were elevated. Echocardiography demonstrated akinesia in all left anterior descending artery territory. The patient underwent angiography, which demonstrated that the left anterior descending artery was totally occluded at the proximal portion. The other coronary arteries were completely normal (Figs 1 and 2). A stent was placed in the left anterior descending artery, and the blood flow was restored (Fig 3). After 3 months, the patient developed ischemic cardiomyopathy. He had a left ventricle ejection fraction of 15 and right ventricle ejection fraction of 15. He is being treated medically for heart failure. Fig 1.

© 2011 by The Society of Thoracic Surgeons Published by Elsevier Inc large paravalvular leak for which he had undergone Amplatzer closure 5 months prior. Laboratory tests confirmed hemolysis, and echocardiography and fluoroscopy showed restricted motion of prosthetic valve leaflet. The patient underwent surgery, which revealed the interference of the Amplatzer in valve mobility (Figs 1 and 2). The Amplatzer was thereafter removed, Fig 2.

30-year-old patient came to our cardiac clinic complaining of exertional dyspnea and a nonspecific chest pain. An echocardiogram showed a mass in the left atrium of about 2 cm, which was highly suggestive of eft atrial myxoma. The pathologic condition was determined by eans of multislice computed tomography, which reconfirmed the ass in the left atrium (Figures 1 and E1). The patient underwent an operation, during which the pathoogic condition was similar to that identified by means of echoardiography and multislice computed tomography (Figure 2, A). he tumor was excised, and the left atrium was closed (Figu , and E2). The patient was weaned off cardiopulmonary by neventfully. He was discharged from the hospital 5 days after the peration.