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Decellularized tissues composed of extracellular matrix (ECM) have been clinically used to support the regeneration of various human tissues and organs. Most decellularized tissues so far have been derived from animals or cadavers. Therefore, despite the many advantages of decellularized tissue, there are concerns about the potential for immunogenicity and the possible presence of infectious agents. Herein, we present a biomaterial composed of ECM derived from human adipose tissue, the most prevalent, expendable, and safely harvested tissue in the human body. The ECM was extracted by successive physical, chemical, and enzymatic treatments of human adipose tissue isolated by liposuction. Cellular components including nucleic acids were effectively removed without significant disruption of the morphology or structure of the ECM. Major ECM components were quantified, including acid/pepsin-soluble collagen, sulfated glycosaminoglycan (GAG), and soluble elastin. In an in vivo experiment using mice, the decellularized ECM graft exhibited good compatibility to surrounding tissues. Overall results suggest that the decellularized ECM containing biological and chemical cues of native human ECM could be an ideal scaffold material not only for autologous but also for allograft tissue engineering.

Extracellular matrix (ECM) provides structural support and biochemical cues for tissue development and regeneration. Here we report a thermosensitive hydrogel composed of soluble ECM (sECM) and methylcellulose (MC) for injectable stem cell delivery. The sECM was prepared by denaturing solid ECM extracted from human adipose tissue and then blended with a MC solution. At low temperatures, the sECM-MC solution displayed a viscous solution state in which the loss modulus (G″) was predominant over the storage modulus (G'). With increasing temperature, G' increased dramatically and eventually exceeded G″ around 34 °C, characteristic of the transition from a liquid-like state to an elastic gel-like state. After a single injection of the stem cell-embedded hydrogel in full thickness cutaneous wound, the wound healed rapidly through re-epithelialization and neovascularization with minimum scar formation. The overall results suggest that in-situ-forming sECM-MC hydrogels are a promising injectable vehicle for stem cell delivery and tissue regeneration.

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Cells in tissues are surrounded by the extracellular matrix (ECM), a gel-like material of proteins and polysaccharides that are synthesized and secreted by cells. Here we propose that the ECM can be isolated from porcine adipose tissue and holds great promise as a xenogeneic biomaterial for tissue engineering and regenerative medicine. Porcine adipose tissue is easily obtained in large quantities from commonly discarded food waste. Decellularization protocols have been developed for extracting an intact ECM while effectively eliminating xenogeneic epitopes and minimally disrupting the ECM composition. Porcine adipose tissue was defatted by homogenization and centrifugation. It was then decellularized via chemical (1.5 M sodium chloride and 0.5% sodium dodecyl sulfate) and enzymatic treatments (DNase and RNase) with temperature control. After decellularization, immunogenic components such as nucleic acids and a-Gal were significantly reduced. However, abundant ECM components, such as collagen (332.9 -12.1 mg/mg ECM dry weight), sulfated glycosaminoglycan (GAG, 85 -0.7 mg/mg ECM dry weight), and elastin (152.6 -4.5 mg/mg ECM dry weight), were well preserved in the decellularized material. The biochemical and mechanical features of a decellularized ECM supported the adhesion and growth of human cells in vitro. Moreover, the decellularized ECM exhibited biocompatibility, longterm stability, and bioinductivity in vivo. The overall results suggest that the decellularized ECM derived from porcine adipose tissue could be useful as an alternative biomaterial for xenograft tissue engineering.