New Standards for hPSC-CM
Human pluripotent stem cells are a viable source for in vitro generation of cardiomyocytes useful for the study of human development, heart disease modeling, and regenerative medicine. As the number of laboratories and studies that utilize pluripotent stem cell-derived cardiomyocytes (hPSC-CM) has grown steadily over the past decade, the ability to accurately and precisely assess cell identity in differentiation cultures remains paramount to well-defined studies that can be replicated among laboratories. The question of how to confidently and accurately measure the percentage of cardiomyocytes within an hPSC-CM culture may seem straightforward. However, while flow cytometry is well-suited for this purpose, there is currently no consensus regarding which marker, antibody, or protocol is best suited to enable comparisons of hPSC-CM culture heterogeneity among experiments or laboratories. This poses serious challenges to evaluating outcomes generated among laboratories and studies.
Our laboratory works to address recent calls for added rigor in biomedical research by developing protocols, reagents, and knowledge that will facilitate reproducible generation, characterization, and selection of well-defined hPSC-CM. By establishing rigorous standards for quality control evaluation of hPSC-CM, we believe our efforts will enhance the use of hPSC-CM in a broad range of research and clinical applications, especially by enabling more accurate comparisons of results among studies.
Our protocols for generation and standardization of flow cytometry assessment can be found here:
Bhattacharya et al., JOVE, 2014; High efficiency differentiation of human pluripotent stem cells to cardiomyocytes and characterization by flow cytometry.
Waas et al., pre-print (manuscript currently in revision); Are these cardiomyocytes? Protocol development reveals impact of sample preparation on the accuracy of identifying cardiomyocytes by flow cytometry
Our long-term goals include the development of cell surface marker "barcodes" that enable identification and isolation of stage- and subtype-specific cardiomyocytes which can then be tested for their suitability for a wide variety of research and clinical applications.