Mechanical Maturation of 3D-Printed Human Induced Pluripotent Stem Cell Derived Cardiomyocytes
Cecillia Lui, MD, Yang Bai, MD, Enoch Yeung, MD, Seungman Park, PhD, Yun Chen, PhD, Chulan Kwon, MS, PhD, Gordon Tomaselli, MD, Gordon Tomaselli, MD, Luca A. Vricella, MD FACS, Narutoshi Hibino, MD.
Johns Hopkins Hospital, Baltimore, MD, USA.
Current tissue engineering efforts to develop a clinically relevant tissue graft from human induced pluripotent stem cells (hiPSCs) have been hindered by the persistent immature character of resultant cardiomyocytes. We hypothesize that mechanical stimulation of 3D printed cardiac tissues created from hiPSC-derived cardiomyocytes (CMs) will result in improved maturation of the graft.
Scaffold-free cardiac tissue graft patches were printed from hiPSC-derived CM cell spheroids using a 3D bioprinter (Regenova, Cyfuse Biomedical K.K., Tokyo, Japan), then either mechanically stimulated by stretching and mounting on to laminin-coated polydimethylsiloxane (PDMS) molds, or otherwise left to culture free-floating in media. After growth, we compared stretched and unstretched patch morphology and sarcomere length (n=3).
Immunofluorescence image analysis demonstrated significantly increased sarcomere length at 1 week and 4 weeks of culture compared to free-floating patches cultured for the same time. Based on this analysis, we expect that traction force microscopy, electromagnetic tweezers, and qPCR will reveal increased patch functional and molecular maturity as a result of mechanical stimulation. We anticipate that beating contractile force will increase, tensile strength by Young’s modulus of the tissues will improve, and genetic markers indicating cardiomyocyte differentiation will be upregulated.
Our studies so far suggest that mechanical stimulation plays an important role in maturation of hiPSC derived-CMs, and represent an incremental but foundational advance toward clinically applicable, scaffold-free human cardiac tissue grafts.
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