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Global Translational Medicine Advancements in cardiac regenerative therapy

Culture medium is a critical component for large- conditions involving factors such as activin A (100 ng/mL)
scale production, impacting both cost and quality control. and BMP4 (10 ng/mL) have demonstrated the potential to
Standard iPSC culture media, such as mTeSR 1 or Essential generate 10 – 10 iPSC-CMs (one to two folds of which
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8 , are commonly used, but their high costs present a are required per patient) in a single run, yielding sufficient
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bottleneck for scalability. On average, these media cost quantities of iPSC-CMs for therapeutic applications in 5 –
$500 – $700/L, with daily consumption in large-scale 10 L volumes within a 2 – 3 week timeframe. Differentiation
bioreactors ranging from 1 – 2 L, depending on cell density efficiencies of 70 – 90% are achieved through these
and bioreactor volume. Thus, media optimization, optimized protocols, meaning 7 – 9 out of every 10 iPSCs
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including potential shifts toward serum-free or chemically successfully differentiate into CMs, depending on the initial
defined formulations, is a key strategy for cost reduction. seeding density and bioreactor volume. 20,108 The estimated
Studies have shown that adjusting key components such as cost for generating these cells, including reagents, media,
GFs (e.g., fibroblast growth factor 2 [FGF and TGF-β) can and labor, ranges from $10,000 to $20,000 per patient dose,
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reduce media consumption by 20 – 30% while maintaining with ongoing efforts aimed to reduce this cost through
high cell viability and pluripotency. 77,78 process optimization and economies of scale. 63,109,110
Scalable production of iPSC-CMs requires meticulous As for process dimensions, estimates indicate that
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optimization of biomolecular and process factors to drive approximately 1 – 10 × 10 (1 – 10 billions) functional
differentiation toward CPCs mimicking the complexity active cells for each patient are required for solid organ
and multipotentiality of first heart field and second restoration, including substituting hepatocytes, pancreatic
heart field. 79-81 Key factors include: (1) transcription β-cells, or CMs. However, significantly larger quantities are
factors: Essential cardiac-specific marker genes such required in producing “in vitro blood,” with calculations
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as GATA4-6, 82,83 HAND1/2, NKX2-5, TBX5, 85,86 and suggesting that around 2 – 3 × 10 human iPSC-derived
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cardiac troponin T (cTnT) must be expressed to initiate red blood cells (iPSC-RBCs) are required to match 5 L of
cardiac development; 10,11 (2) signaling pathways: activation blood in adults, considering that 1 millimeter of blood
of pathways such as activin A, Wnt/β-catenin, and contains approximately 5 billion erythrocytes. 43
BMP/TGF-β to regulate lineage specification; (3) GFs and Calculations derived from experimental data indicate
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cytokines: supplementation with FGF, VEGF, BMP4, that current production of one billion human iPSC-CMs
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and cytokines such as IL-6 and IL-11 supports demands a bioprocess scale of 1 – 2.5 L. This implies
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directed differentiation; (4) extracellular matrix (ECM) that even with substantial future advancements, mass
components: collagen, fibronectin, and laminin in synthetic production of iPSC progenies will demand industrial-
scaffolds or decellularized matrices create an ideal cellular level procedures, which have already been developed for
environment, enhancing maturation; 93-95 (5) cell culture producing recombinant proteins or vaccines in mammalian
conditions: controlled oxygen levels, pH, and nutrient cell cultures at scales of approximately 1,000 L. In
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flow are crucial for maintaining cell viability; 96,97 (6) timing contrast, bioprocess development for iPSCs remains in its
and duration: the schedule and length of exposure to nascent stage, requiring the further advancement to meet
these cues directly impact differentiation efficiency; 98 industrial demands.
(7) iPSC line quality: the initial quality and pluripotency
of the iPSC line affect differentiation outcomes; 99,100 However, it is worth noting that STBs are not 3D
(8) reprogramming method: the method of iPSC systems in the same way as other bioreactor types, such as
3D suspension bioreactors. While STBs remain useful for
generation shapes the epigenetic profile and influences large-scale production, advancements in 3D cultures have
differentiation potential; 101,102 (9) epigenetic modifications: been increasingly explored to enhance the differentiation
DNA methylation and histone modifications regulate and maturation of iPSC-derived cells. These systems allow
cardiac gene expression throughout differentiation; and for more complex interactions, potentially improving both
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(10) mechanical forces and biophysical cues: shear stress the yields and functionalities of differentiated cells, though
and ES enhance maturation and functional rhythm. 104-107
STBs still provide a reliable and scalable approach for
The use of stirred tank bioreactors (STBs) remains achieving high-yield production. Some of the latest scalable
a widely employed method for scalable iPSC-CM methods include: (1) vertical-wheel bioreactors: designed
production, particularly for generating high-yield to reduce shear stress using a gentler mixing mechanism
quantities. Parameters such as medium composition, compared to traditional impeller-based stirred tanks,
ECM scaffold selection, and precise biochemical signaling potentially improving cell viability and differentiation
are essential to ensure consistency and reproducibility. In consistency, (2) microcarrier-based systems: By allowing
current large-scale differentiation protocols, optimized iPSCs to attach and grow on microcarriers, these systems

Volume 4 Issue 1 (2025) 8 doi: 10.36922/gtm.5745