An overview of tissue and whole organ decellularization processes

Abstract

Biologic scaffold materials composed of extracellular matrix (ECM) are typically derived by processes that involve decellularization of tissues or organs. Preservation of the complex composition and three-dimensional ultrastructure of the ECM is highly desirable but it is recognized that all methods of decellularization result in disruption of the architecture and potential loss of surface structure and composition. Physical methods and chemical and biologic agents are used in combination to lyse cells, followed by rinsing to remove cell remnants. Effective decellularization methodology is dictated by factors such as tissue density and organization, geometric and biologic properties desired for the end product, and the targeted clinical application. Tissue decellularization with preservation of ECM integrity and bioactivity can be optimized by making educated decisions regarding the agents and techniques utilized during processing. An overview of decellularization methods, their effect upon resulting ECM structure and composition, and recently described perfusion techniques for whole organ decellularization techniques are presented herein.

Figure 1

Example decellularization protocols for (A) thin laminates such as pericardium, (B) thicker laminates such as dermis, (C) fatty, amorphous tissues such as adipose, (D) composite tissues or whole simple organs such as trachea, and (E) whole vital organs such as liver. Arrow lengths represent relative exposure times for each processing step. Rinse steps for agent removal and sterilization methods are not shown to simplify comparison. (F) Representative images of the gross appearance of intact rat liver subjected to decellularization: (left to right) before, during, and after decellularization; decellularized liver perfused with blue dye. (G) Representative photomicrographs showing no nuclear staining after whole organ decellularization: (left to right) native rat liver H&E; decellularized liver ECM H&E; native rat liver DAPI; liver-ECM DAPI. Scale bars are 50 μm.

Figure 2

Quantification of (A) residual DNA and (B) ECM yield after decellularization of porcine spinal cord. DNA was quantified by PicoGreen assay (Invitrogen, Carlsbad, CA, USA). Yield is per unit mass of lyophilized ECM. Sample size is 3 for all groups.