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Purpose of Review: The advent of induced pluripotent stem cells (iPSC) has paved the way for new in vitro models of human cardiomyopathy. Herein, we will review existing models of disease as well as strengths and limitations of the system., Recent Findings: Preclinical studies have now demonstrated that iPSCs generated from patients with both acquired or heritable genetic diseases retain properties of the disease in vitro and can be used as a model to study novel therapeutics. iPSCs can be differentiated in vitro into the cardiomyocyte lineage into cells resembling adult ventricular myocytes that retain properties of cardiovascular disease from their respective donor. iPSC pluripotency allows for them to be frozen, stored, and continually used to generate iPSC-derived myocytes for future experiments without need for invasive procedures or repeat myocyte isolations to obtain animal or human cardiac tissues. While not without their limitations, iPSC models offer new ways for studying patient-specific cardiomyopathies. iPSCs offer a high-throughput avenue for drug development, modeling of disease pathophysiology in vitro, and enabling experimental repair strategies without need for invasive procedures to obtain cardiac tissues., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Cardiac- (CSC) and mesenchymal-derived (MSC) CD117+ isolated stem cells improve cardiac function after injury. However, no study has compared the therapeutic benefit of these cells when used autologously., Methods: MSCs and CSCs were isolated on day 0. Cardiomyopathy was induced (day 28) by infusion of L-isoproterenol (1,100 ug/kg/hour) from Alzet minipumps for 10 days. Bromodeoxyuridine (BrdU) was infused via minipumps (50 mg/mL) to identify proliferative cells during the injury phase. Following injury (day 38), autologous CSC (n = 7) and MSC (n = 4) were delivered by intracoronary injection. These animals were compared to those receiving sham injections by echocardiography, invasive hemodynamics, and immunohistochemistry., Results: Fractional shortening improved with CSC (26.9 ± 1.1% vs. 16.1 ± 0.2%, p = 0.01) and MSC (25.1 ± 0.2% vs. 12.1 ± 0.5%, p = 0.01) as compared to shams. MSC were superior to CSC in improving left ventricle end-diastolic (LVED) volume (37.7 ± 3.1% vs. 19.9 ± 9.4%, p = 0.03) and ejection fraction (27.7 ± 0.1% vs. 19.9 ± 0.4%, p = 0.02). LVED pressure was less in MSC (6.3 ± 1.3 mmHg) as compared to CSC (9.3 ± 0.7 mmHg) and sham (13.3 ± 0.7); p = 0.01. LV BrdU+ myocytes were higher in MSC (0.17 ± 0.03%) than CSC (0.09 ± 0.01%) and sham (0.06 ± 01%); p < 0.001., Conclusions: Both CD117+ isolated CSC and MSC therapy improve cardiac function and attenuate pathological remodeling. However, MSC appear to confer additional benefit., (© 2015 Wiley Periodicals, Inc.)

Myocardial water content and infarct size were studied in 39 pigs randomly assigned to a nonintervention group, a group with an intracoronary infusion of a control solution, and a group with a hyperosmotic infusion to 450 mosM by the addition of D-mannitol. The intracoronary solutions were selectively infused into the left anterior descending coronary artery just distal to the occlusion site starting 48 min after occlusion. Reperfusion was performed 3 min later and the infusion rate progressively tapered off over the following 33 min. Multiple myocardial fragments were then obtained in nine pigs, from endocardial, mesocardial, and epicardial regions of the ischemic and control myocardium. Water content measured after 48 h of dessication was significantly greater in the reperfused [530 +/- 7 ml/100 (mean +/- SE) g dry wt] compared with control myocardium (374 +/- 3; P less than 0.0001) and similar in reperfused control and isotonic infusion groups (556 +/- 7 and 543 +/- 8 ml/100 g dry wt); it was 491 +/- 11 with intracoronary D-mannitol infusion, representing 35% less increase (P less than 0.001). In the 30 remaining pigs, area at risk and infarct size were measured 24 h later by in vivo fluorescein and in vitro triphenyltetrazolium chloride. Infarct size was similar in control and in the isotonic reperfused hearts, 6.80 +/- 1.05 and 6.22 +/- 0.76% of ventricular weight, and smaller with D-mannitol, 4.46 +/- 0.46 (P less than 0.05). The ratio of infarct size to area at risk was also smaller [0.415 +/- 0.029 vs. 0.543 +/- 0.052 and 0.547 +/- 0.045 (P less than 0.02)].(ABSTRACT TRUNCATED AT 250 WORDS)