The heart is a highly organized organ that regularly and rhythmically pumps blood throughout the body. When heart tissue suffers from ischemia, the injured myocardium is not fully repaired due to its low proliferative capacity. Subsequent fibrosis leads to structural remodeling followed by congestive heart failure. Currently, apart from heart transplantation, no curative therapy is available for the failing heart. To address this medical issue, extensive research has been dedicated to developing cardiac regeneration therapies. For cell therapy to replace the fibrotic myocardium in failing hearts, the most promising cell source is induced pluripotent stem cells (iPSCs). iPSC-derived cardiomyocytes can be produced with optimized differentiation protocols and have been approved for clinical use. However, concerns remain regarding their structural and functional immaturity and the risk of tumorigenic undifferentiated cell contamination. Recent advances in regenerative medicine and bioengineering have been overcoming these hurdles. This review summarizes the history and current status of clinical application of iPSC-derived cardiomyocytes. Additionally, potential utilities of animal-derived iPSCs in veterinary medicine are also discussed particularly focusing on canine and feline cardiology.

The interval between the peak and end of the T-wave and the QT ratio (TpTe : QT) reflects the degree of repolarization heterogeneity in the myocardium and has high sensitivity for ventricular arrhythmia and mortality in humans. Based on this, the authors hypothesized that these markers are related to the myocardial pathological progression in canine dilated cardiomyopathy (DCM). The present report is a retrospective cohort study of Stage B2 DCM dogs diagnosed by experienced cardiology clinicians. Cases that died within two years after diagnosis were defined as the Early Mortality and all other cases were categorized as Controls. The TpTe : QT values were obtained by standard limb electrocardiogram and measured using the tangent method. The area under the curve (AUC) was used as the cutoff criteria for identifying the Early Mortality group. Out of 21 cases, 10 cases reached Early Mortality, while the remaining 11 cases were classified into the Control group. TpTe : QT showed a high AUC value with an optimal cutoff of 0.20 (sensitivity 89%, specificity 92%; AUC 0.90). In conclusion, TpTe : QT could be a potential prognostic indicator for Stage B2 DCM dogs. This study provided valuable information as a preliminary stage for a larger-scale clinical study to be conducted in the future.