scholarly journals Effect of Real-Time Leak Current Correction on Action Potentials Recorded from Induced Pluripotent Stem Cell-Derived Cardiac Myocytes

2019 ◽  
Vol 116 (3) ◽  
pp. 100a
Author(s):  
Brian Panama ◽  
Mark Nowak ◽  
Brandon Franks ◽  
Leigh Korbel ◽  
Glenna Bett ◽  
...  
2017 ◽  
Vol 26 (4) ◽  
pp. 613-624 ◽  
Author(s):  
Scott C. Vermilyea ◽  
Jianfeng Lu ◽  
Miles Olsen ◽  
Scott Guthrie ◽  
Yunlong Tao ◽  
...  

Induced pluripotent stem cell (iPSC)-derived neurons represent an opportunity for cell replacement strategies for neurodegenerative disorders such as Parkinson's disease (PD). Improvement in cell graft targeting, distribution, and density can be key for disease modification. We have previously developed a trajectory guide system for real-time intraoperative magnetic resonance imaging (RT-IMRI) delivery of infusates, such as viral vector suspensions for gene therapy strategies. Intracerebral delivery of iPSC-derived neurons presents different challenges than viral vectors, including limited cell survival if cells are kept at room temperature for prolonged periods of time, precipitation and aggregation of cells in the cannula, and obstruction during injection, which must be solved for successful application of this delivery approach. To develop procedures suitable for RT-IMRI cell delivery, we first performed in vitro studies to tailor the delivery hardware (e.g., cannula) and defined a range of parameters to be applied (e.g., maximal time span allowable between cell loading in the system and intracerebral injection) to ensure cell survival. Then we performed an in vivo study to evaluate the feasibility of applying the system to nonhuman primates. Our results demonstrate that the RT-IMRI delivery system provides valuable guidance, monitoring, and visualization during intracerebral cell delivery that are compatible with cell survival.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
LouJin Song ◽  
Masayuki Yazawa

Human induced pluripotent stem cell (iPSC)-based model of cardiac diseases has been proved to be useful and valuable for identifying new therapeutics. However, the use of human iPSC-based model of cardiac diseases for drug screen is hampered by the high-cost and complexity of methods used for reprogramming, in vitro differentiation, and phenotyping. To address the limitations, we first optimized a protocol for reprogramming of human fibroblasts and keratinocytes into pluripotency using single lipofection and the episomal vectors in a 24-well plate format. This method allowed us to generate multiple lines of integration-free and feeder-free iPSCs from seven patients with cardiac diseases and three controls. Second, we differentiated human iPSCs derived from Timothy syndrome patients into cardiomyocytes using a monolayer differentiation method. We found that Timothy syndrome cardiomyocytes showed slower, irregular contractions and abnormal calcium handling compared to controls, which were consistent with previous reports using a retroviral method for reprogramming and using an embryoid body-based method for cardiac differentiation. Third, we developed an efficient approach for recording action potentials and calcium transients simultaneously in control and patient cardiomyocytes using genetically encoded fluorescent indicators, ArcLight and R-GECO1. The dual optical recordings enabled us to observe prolonged action potentials and abnormal calcium handling in Timothy syndrome cardiomyocytes. We confirmed that roscovitine rescued the phenotypes in Timothy syndrome cardiomyocytes and these findings were consistent with previous studies using conventional electrophysiological recordings and calcium imaging with dyes. The approaches using our optimized methods and dual optical recordings will improve iPSC applicability for disease modeling to test potential therapeutics. With those new approaches in hand, next we plan to use the iPSC-based model of Timothy syndrome to investigate novel molecules involved in the pathogenesis of Timothy syndrome and to screen and identify new therapeutic compounds for Timothy syndrome patients.


2019 ◽  
Vol 116 (3) ◽  
pp. 671-685 ◽  
Author(s):  
Xi Lou ◽  
Meng Zhao ◽  
Chengming Fan ◽  
Vladimir G Fast ◽  
Mani T Valarmathi ◽  
...  

Abstract Aims In regenerative medicine, cellular cardiomyoplasty is one of the promising options for treating myocardial infarction (MI); however, the efficacy of such treatment has shown to be limited due to poor survival and/or functional integration of implanted cells. Within the heart, the adhesion between cardiac myocytes (CMs) is mediated by N-cadherin (CDH2) and is critical for the heart to function as an electromechanical syncytium. In this study, we have investigated whether the reparative potency of human-induced pluripotent stem cell-derived cardiac myocytes (hiPSC-CMs) can be enhanced through CDH2 overexpression. Methods and results CDH2-hiPSC-CMs and control wild-type (WT)-hiPSC-CMs were cultured in myogenic differentiation medium for 28 days. Using a mouse MI model, the cell survival/engraftment rate, infarct size, and cardiac functions were evaluated post-MI, at Day 7 or Day 28. In vitro, conduction velocities were significantly greater in CDH2-hiPSC-CMs than in WT-hiPSC-CMs. While, in vivo, measurements of cardiac functions: left ventricular (LV) ejection fraction, reduction in infarct size, and the cell engraftment rate were significantly higher in CDH2-hiPSC-CMs treated MI group than in WT-hiPSC-CMs treated MI group. Mechanistically, paracrine activation of ERK signal transduction pathway by CDH2-hiPSC-CMs, significantly induced neo-vasculogenesis, resulting in a higher survival of implanted cells. Conclusion Collectively, these data suggest that CDH2 overexpression enhances not only the survival/engraftment of cultured CDH2-hiPSC-CMs, but also the functional integration of these cells, consequently, the augmentation of the reparative properties of implanted CDH2-hiPSC-CMs in the failing hearts.


2017 ◽  
Vol 26 (23) ◽  
pp. 1695-1705 ◽  
Author(s):  
Gary Duncan ◽  
Karl Firth ◽  
Vinoj George ◽  
Minh Duc Hoang ◽  
Andrew Staniforth ◽  
...  

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