Induced pluripotent stem cell-derived gamete-associated proteins incite rejection of induced pluripotent stem cells in syngeneic mice

Engineering Human Cardiac Muscle Patch Constructs for Prevention of Post-infarction LV Remodeling

Tissue engineering combines principles of engineering and biology to generate living tissue equivalents for drug testing, disease modeling, and regenerative medicine. As techniques for reprogramming human somatic cells into induced pluripotent stem cells (iPSCs) and subsequently differentiating them into cardiomyocytes and other cardiac cells have become increasingly efficient, progress toward the development of engineered human cardiac muscle patch (hCMP) and heart tissue analogs has accelerated. A few pilot clinical studies in patients with post-infarction LV remodeling have been already approved. Conventional methods for hCMP fabrication include suspending cells within scaffolds, consisting of biocompatible materials, or growing two-dimensional sheets that can be stacked to form multilayered constructs. More recently, advanced technologies, such as micropatterning and three-dimensional bioprinting, have enabled fabrication of hCMP architectures at unprecedented spatiotemporal resolution. However, the studies working on various hCMP-based strategies for in vivo tissue repair face several major obstacles, including the inadequate scalability for clinical applications, poor integration and engraftment rate, and the lack of functional vasculature. Here, we review many of the recent advancements and key concerns in cardiac tissue engineering, focusing primarily on the production of hCMPs at clinical/industrial scales that are suitable for administration to patients with myocardial disease. The wide variety of cardiac cell types and sources that are applicable to hCMP biomanufacturing are elaborated. Finally, some of the key challenges remaining in the field and potential future directions to address these obstacles are discussed.

Induction of mesenchymal stem cell‑like transformation in rat primary glial cells using hypoxia, mild hypothermia and growth factors

The transformation of rat primary glial cells into mesenchymal stem cells (MSCs) is intriguing as more seed cells can be harvested. The present study aimed to evaluate the effects of growth factors, hypoxia and mild hypothermia on the transformation of primary glial cells into MSCs. Rat primary glial cells were induced to differentiate by treatment with hypoxia, mild hypothermia and basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). Immunohistochemistry and western blotting were then used to determine the expression levels of glial fibrillary acidic protein (GFAP), nestin, musashi-1, neuron specific enolase (NSE) and neuronal nuclei (NeuN), in each treatment group. bFGF and EGF increased the proportion of CD44⁺ and CD105⁺ cells, while anaerobic mild hypothermia increased the proportion of CD90⁺ cells. The combination of bFGF and EGF, and anaerobic mild hypothermia increased the proportion of CD29⁺ cells and significantly decreased the proportions of GFAP⁺ cells and NSE⁺ cells. Treatment of primary glial cells with bFGF and EGF increased the expression levels of nestin, Musashi-1, NSE and NeuN. Anaerobic mild hypothermia increased the expression levels of Musashi-1 and decreased the expression levels of NSE and NeuN in glial cells. The results of the present study demonstrated that bFGF, EGF and anaerobic mild hypothermia treatments may promote the transformation of glial cells into MSC-like cells, and that the combination of these two treatments may have the optimal effect.

Tumorigenic and Immunogenic Properties of Induced Pluripotent Stem Cells: a Promising Cancer Vaccine

Induced pluripotent stem cells (iPSCs) are mainly characterized by their unlimited proliferation abilities and potential to develop into almost any cell type. The creation of this technology has been of great interest to many scientific fields, especially regenerative biology. However, concerns about the safety of iPSC application in transplantation have arisen due to the tumorigenic and immunogenic properties of iPSCs. This review will briefly introduce the developing history of somatic reprogramming and applications of iPSC technology in regenerative medicine. In addition, the review will highlight two challenges to the efficient usage of iPSCs and the underlying mechanisms of these challenges. Finally, the review will discuss the expanding application of iPSC technology in cancer immunotherapy as a potential cancer vaccine and its advantages in auxiliary treatment compared with oncofetal antigen-based and embryonic stem cell (ESC)-based vaccines.

MHC matching fails to prevent long-term rejection of iPSC-derived neurons in non-human primates

Cell therapy products (CTP) derived from pluripotent stem cells (iPSCs) may constitute a renewable, specifically differentiated source of cells to potentially cure patients with neurodegenerative disorders. However, the immunogenicity of CTP remains a major issue for therapeutic approaches based on transplantation of non-autologous stem cell-derived neural grafts. Despite its considerable side-effects, long-term immunosuppression, appears indispensable to mitigate neuro-inflammation and prevent rejection of allogeneic CTP. Matching iPSC donors' and patients' HLA haplotypes has been proposed as a way to access CTP with enhanced immunological compatibility, ultimately reducing the need for immunosuppression. In the present work, we challenge this paradigm by grafting autologous, MHC-matched and mis-matched neuronal grafts in a primate model of Huntington's disease. Unlike previous reports in unlesioned hosts, we show that in the absence of immunosuppression MHC matching alone is insufficient to grant long-term survival of neuronal grafts in the lesioned brain.