Clinical Regenerative Medicine in Urology by Bup Wan Kim

Author:Bup Wan Kim
Language: eng
Format: epub
Publisher: Springer Singapore, Singapore

7.4.1.2 Decellularized Cadaveric Scaffold

Artificial scaffold also can be generated from organs of animal or human’s cadaver through decellularization [173–176]. The decellularization process can remove DNA, cellular material, and cell surface antigens from the extracellular matrix scaffold while preserving the structural and functional characteristics of vascular channels. The process of decellularization includes the repeated irrigation of cadaveric organs with acids or detergents through the innate vasculature, although organs with higher fat component, such as pancreas, often require the addition of lipid solvents [177]. To generate cadaveric scaffold, complete decellularization must be achieved because residual cellular material may contain antigenic epitopes that trigger inflammatory reactions and compromise subsequent recellularization [178, 179]. Ethylene oxide or paracetic acid can effectively sterilized the extracellular matrix without denaturing the extracellular matrix proteins or growth factors after decellularization [180, 181].

Using this technique, a functional artificial rat heart using a cadaveric heart as a scaffold was successfully generated [182]. For this, a whole-heart scaffold with intact three-dimensional geometry and vasculature was created via coronary perfusion with detergents into the cadaveric heart, followed by repopulation with neonatal cardiac cells or rat aortic endothelial cells and cultured under physiological conditions to stimulate organ maturation. In this study, the injected neonatal cardiac cells formed a contractile myocardium, which performed the stroke function. Decellularized cadaveric scaffolds have also been used to generate other organs, such as the liver, respiratory tract, and urinary bladder [183–185].

Recent advancement of decellularization-recellularization technique enabled to generate more complex organs, such as the kidney. Ross et al. first reported successful regeneration of an entire kidney using the decellularized rat kidney as a scaffold [186]. After fabricating intact scaffold, murine embryonic stem cells were injected through the innate vasculature. In this study, embryonic stem cells were used for seeding population because of their high doubling capacity, pluripotency, and potential to differentiate and integrate into primordial kidney cultures. The kidney scaffold successfully supported the growth and migration of the seeded embryonic stem cells within glomerular, vascular, and tubular structures while inducing differentiation down renal cell lines. Immunohistochemical analysis indicated that the seeded embryonic stem cells had lost their embryonic appearance and had shown gross morphological changes consistent with mature kidney cells, as well as expression of immunohistochemical markers of renal differentiation, such as Pax-2, Ksp-cadherin, and pan-cytokeratin. Through this study, the authors suggested several points to advance this research field that pretreatment of the embryonic stem cell with prodifferentiation agents, such as retinoic acid, activin-A, and BMP-7, may promote implantation and proliferation by providing a more kidney-specific lineage. Moreover, while injected cells through innate vascular channels can be evenly distributed in the renal cortex, the cells may not localize in the collecting system. Thus, retrograde seeding via ureter was attempted to resolve this problem, but this method caused uneven cell dispersion. Furthermore, murine scaffolds are not feasible for adult human kidney regeneration in terms of size and structure. Therefore, organs of larger animals, such as pig, or primates had to be considered to be investigated using this technique to meet human renal requirements.

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