Porcine Small Intestine Submucosa for Soft Tissue Augmentation

Wound-healing effect of adipose stem cell-derived extracellular matrix sheet on full-thickness skin defect rat model: Histological and immunohistochemical study

The potential use of extracellular matrix (ECM) as a source of wound dressing material has recently received much attention. The ECM is an intricate network of various combinations of elastin, collagens, laminin, fibronectin, and proteoglycans that play a key role in stimulating cell proliferation and differentiation. We evaluated the efficacy of an ECM sheet derived from human adipose tissue as a wound dressing material to enhance healing. We prepared a novel porous ECM sheet dressing scaffold from human adipose tissue. in vitro analysis of the ECM sheets showed efficient decellularisation; absence of immunostimulatory components; and the presence of a wide number of angiogenic and bioactive factors, including collagen, elastin, and proteoglycans. To evaluate in vivo efficacy, full-thickness excisional wounds were created on the dorsal skin of a rat, and the ECM sheets; secondary healing foam wound dressing, Healoderm; or a conventional dressing were applied to each wound site. Photographs were taken every other day, and the degree of reepithelialisation of the wounds was determined. Application of an ECM sheet dressing enhanced the macroscopic wound-healing rate on days 4, 7, and 10 compared with that in the control group. Microscopic analysis indicated that the reepithelialisation rate of the wound was higher in the ECM group compared with that in the control group; the reepithelialisation rate was better than that of the secondary healing foam wound dressing. Moreover, a denser and more organised granulation tissue was formed in the ECM sheet group compared with that in the secondary healing foam wound dressing and control groups. The ECM sheet also showed the highest microvessel density compared with the secondary healing foam wound dressing and control groups. Based on these data, we suggest that a bioactive ECM sheet dressing derived from human adipose can provide therapeutic proteins for wound healing.

Design and characterization of tissue-specific extracellular matrix-derived microcarriers

The three-dimensional (3D) extracellular matrix (ECM) environment plays a critical role in mediating normal cellular behavior and tissue organization. While commercially available microcarriers have shown promise, limited research has been conducted on the design of tissue-specific, custom-fabricated microcarriers, engineered to mimic the composition of the native ECM of cells or tissues of interest. Moving toward this goal, methods were developed to fabricate microcarriers from decellularized adipose tissue (DAT) via minimally-cytotoxic protocols. Characterization by microscopy confirmed the production of stable spherical microcarriers, with a microporous surface topography and porous interior. The mean diameter of the DAT microcarriers was 934±51 μm, while the porosity was estimated as 29%±4% using liquid displacement. Stability and swelling behavior over 4 weeks indicated that the DAT microcarriers were effectively stabilized with the photochemical crosslinking agent rose bengal, with total protein release in a simulated physiological environment remaining below 10 μg/mL at all time points. Preliminary cell culture studies with human adipose-derived stem cells (ASCs) in a spinner flask system indicated enhanced cell attachment and proliferation of ASCs on DAT microcarriers over 14 days, as compared with gelatin control microcarriers fabricated using similar methods. Testing confirmed injectability of the DAT microcarriers, further supporting the clinical potential of the approach for localized cell delivery and small volume augmentation in plastic and reconstructive surgery. Overall, tissue-specific microcarriers prepared from solubilized DAT were found to be highly supportive of human ASCs cultured in a 3D dynamic environment.

Decellularized extracellular matrix derived from human adipose tissue as a potential scaffold for allograft tissue engineering

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.

Fabrication of porous extracellular matrix scaffolds from human adipose tissue

Adipose tissue is found over the whole body and easily obtained in large quantities with minimal risk by a common surgical operation, liposuction. Although liposuction was originally intended for the removal of undesired adipose tissue, it may provide an ideal material for tissue engineering scaffolds. Here we present novel, porous scaffolds prepared from human adipose tissues. The scaffolds were fabricated in a variety of macroscopic shapes such as round dishes, squares, hollow tubes, and beads. The microscopic inner porous structure was controlled by the freezing temperature, with a decrease in pore size as the freezing temperature decreased. The scaffold prepared from human adipose tissue contains extracellular matrix components including collagen. Preliminary in vitro studies showed that human adipose-derived stem cells attached to a human extracellular matrix scaffold and proliferated. This scaffold based on human adipose tissue holds great promise for many clinical applications in regenerative medicine, particularly in patients requiring soft-tissue regeneration.

Human extracellular matrix (ECM) powders for injectable cell delivery and adipose tissue engineering

Here, we present extracellular matrix (ECM) powders derived from human adipose tissue as injectable cell delivery carriers for adipose tissue engineering. We postulate that human adipose tissue may provide an ideal biomaterial because it contains large amounts of ECM components including collagen. Fresh human adipose tissue was obtained by a simple surgical operation (liposuction). After removing blood and oil components, the tissue was homogenized, centrifuged, freeze-dried, and ground to powders by milling. In an in vitro study, the human ECM powders were highly effective for promotion of cell attachment and proliferation for three-dimensional (3D) cell culture. In in vivo studies, suspensions of human ECM powders containing human adipose-derived stem cells (hASCs) were subcutaneously injected into nude mice. At eight weeks post-injection, numerous blood vessels were observed and the newly formed tissue exhibited adipogenesis with accumulated intracellular small lipid droplets. Overall, the grafts showed well-organized adipose tissue constructs without any signs of tissue necrosis, cystic spaces, or fibrosis. We believe that human ECM powders could act as efficient injectable biomaterials for tissue engineering and have great potential for meeting clinical challenges in regenerative medicine, particularly in relation to adipose tissue engineering.