Transplantation of Human-induced Pluripotent Stem Cell-derived Cardiomyocytes Is Superior to Somatic Stem Cell Therapy for Restoring Cardiac Function and Oxygen Consumption in a Porcine Model of Myocardial Infarction

Recent progress in induced pluripotent stem cell-derived cardiac cell sheets for tissue engineering

The past decade has witnessed remarkable development in tissue engineering technologies and stem cells. Our lab has developed a novel technology - "cell sheet technology" for tissue engineering. After the confluent cells are cultured on an innovative temperature-responsive culture dish, the cells can be harvested as an intact sheet by lowering temperature. We have successfully created multiple cell sheet-based tissues for therapies of a vast variety of diseases, in particular, myocardial diseases. On the other side, the discovery of human induced pluripotent stem cells (hiPSC) enables stable production of defined tissue-specific cell types and thus makes it possible to regenerate tissues or even organs for clinical application and in vitro drug screening/disease modeling. Recently, we have combined cell sheet technology and hiPSC-derived cardiac cells for fabrication of functional human cardiac tissues. This review summarizes ongoing challenges in this field and our progresses in solving issues, such as large scale culture of hiPSC-derived cardiac cells, elimination of undifferentiated iPSCs to decrease the risk of tumor formation as well as myocardial tissue fabrication technologies.

Cardiac tissue engineering therapeutic products to enhance myocardial contractility

Researchers continue to develop therapeutic products for the repair and replacement of myocardial tissue that demonstrates contractility equivalent to normal physiologic states. As clinical trials focused on pure adult stem cell populations undergo meta-analysis for preclinical through clinical design, the field of tissue engineering is emerging as a new clinical frontier to repair the myocardium and improve cardiac output. This review will first discuss the three primary tissue engineering product themes that are advancing in preclinical to clinical models: (1) cell-free scaffolds, (2) scaffold-free cellular, and (3) hybrid cell and scaffold products. The review will then focus on the products that have advanced from preclinical models to clinical trials. In advancing the cardiac regenerative medicine field, long-term gains towards discovering an optimal product to generate functional myocardial tissue and eliminate heart failure may be achieved.

Adequate taylor couette flow-mediated shear stress is useful for dissociating human iPS cell-derived cell aggregates

Pluripotent stem cell including induced pluripotent stem cells (iPSC) are promising cell sources for regenerative medicine and for three-dimensional suspension culture technologies which may enable the generation of robust numbers of desired cells through cell aggregation. Although manual procedure is widely used for dissociating cell aggregates, the development of non-manual procedures using devices will contribute to efficient cell manufacturing. In the present study, we developed novel cell aggregate dissociation devices with a rotating cylinder inside based on taylor couette flow-mediated shear stress. The shear stress can be increased according to an increase in the size of the rotating cylinder inside the devices and the rotation rate. Adequate device size and suitable rotation rate efficiently dissociated cell aggregates after the undifferentiated expansion and the cardiac differentiation of human iPSC. These finding suggest that non-manual device procedure might be useful for harvesting single cells from human iPSC-derived cell aggregates.

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The newly device successfully generates taylor couette flow.

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Shear stress levels according to the different types of device and rotation rates are quantified through the flow analysis.

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Taylor couette flow-mediated adequate shear stress dissociate cell aggregates from human iPS cells.

[Pluripotent stem cells for the treatment of heart failure: current status, persisting issues and perspectives]

Although the first wave of cell therapy trials has not commonly yielded clinically meaningful improvements, some encouraging hints have emerged which suggest that stem cells or their secreted products could ultimately find a place within the armamentarium of therapies that can be offered to patients with heart failure. In this setting, pluripotent stem cells raise a particular interest because of their unique ability to generate lineage-specific cells which can be transplanted at the desired stage of differentiation. This review discusses the current status of research in this field, the persisting roadblocks that need to be overcome and the approaches which might hasten the clinical applications of this cell type.

Vascularization of Engineered Spatially Patterned Myocardial Tissue Derived From Human Pluripotent Stem Cells in vivo

Tissue engineering approaches to regenerate myocardial tissue after disease or injury is promising. Integration with the host vasculature is critical to the survival and therapeutic efficacy of engineered myocardial tissues. To create more physiologically oriented engineered myocardial tissue with organized cellular arrangements and endothelial interactions, randomly oriented or parallel-aligned microfibrous polycaprolactone scaffolds were seeded with human pluripotent stem cell-derived cardiomyocytes (iCMs) and/or endothelial cells (iECs). The resultant engineered myocardial tissues were assessed in a subcutaneous transplantation model and in a myocardial injury model to evaluate the effect of scaffold anisotropy and endothelial interactions on vascular integration of the engineered myocardial tissue. Here we demonstrated that engineered myocardial tissue composed of randomly oriented scaffolds seeded with iECs promoted the survival of iECs for up to 14 days. However, engineered myocardial tissue composed of aligned scaffolds preferentially guided the organization of host capillaries along the direction of the microfibers. In a myocardial injury model, epicardially transplanted engineered myocardial tissues composed of randomly oriented scaffolds seeded with iCMs augmented microvessel formation leading to a significantly higher arteriole density after 4 weeks, compared to engineered tissues derived from aligned scaffolds. These findings that the scaffold microtopography imparts differential effect on revascularization, in which randomly oriented scaffolds promote pro-survival and pro-angiogenic effects, and aligned scaffolds direct the formation of anisotropic vessels. These findings suggest a dominant role of scaffold topography over endothelial co-culture in modulating cellular survival, vascularization, and microvessel architecture.

CXCL4/PF4 is a predictive biomarker of cardiac differentiation potential of human induced pluripotent stem cells

Selection of human induced pluripotent stem cell (hiPSC) lines with high cardiac differentiation potential is important for regenerative therapy and drug screening. We aimed to identify biomarkers for predicting cardiac differentiation potential of hiPSC lines by comparing the gene expression profiles of six undifferentiated hiPSC lines with different cardiac differentiation capabilities. We used three platforms of gene expression analysis, namely, cap analysis of gene expression (CAGE), mRNA array, and microRNA array to efficiently screen biomarkers related to cardiac differentiation of hiPSCs. Statistical analysis revealed candidate biomarker genes with significant correlation between the gene expression levels in the undifferentiated hiPSCs and their cardiac differentiation potential. Of the candidate genes, PF4 was validated as a biomarker expressed in undifferentiated hiPSCs with high potential for cardiac differentiation in 13 additional hiPSC lines. Our observations suggest that PF4 may be a useful biomarker for selecting hiPSC lines appropriate for the generation of cardiomyocytes.