Gingiva and Periodontal Tissue Regeneration
Vincenzo Guarino, Marco Antonio Alvarez-Pérez in Current Advances in Oral and Craniofacial Tissue Engineering, 2020
The future challenge for 3D tissue engineering in the field of regenerative therapy is the development of 3D tissue constructs without hydrogels. One of the recently developed hydrogel-free approaches is the use of a decellularized Extracellular Matrix (dECM) as a native scaffold (Badylak et al. 2011). This approach was first reported by Cho et al. (Pati et al. 2014), who fabricated the complex channel structure with dECM, using 3D printing technology. Despite this success, numerous issues remain, the most significant being the potential removal of the various types of molecules in the ECM during the decellularization process. Therefore, the mechanical properties of fabricated tissues remain less strong as compared to those of native tissues. Another example of hydrogel-free approaches is the use of cellular aggregates, such as spheroids. Hydrogel-free tubular tissues have been created by the 3D printing of spheroids into a needle array (Itoh et al. 2015). These approaches may overcome the limitations of the hydrogels, but their potential is still being investigated. The understanding and methodology developed in the hydrogel microfabrication can contribute to the advancements in hydrogel free technologies.
Biological reactions to reconstructive materials
Steven J. Kronowitz, John R. Benson, Maurizio B. Nava in Oncoplastic and Reconstructive Management of the Breast, 2020
The decellularization process involves a balance between the competing aims of complete removal of antigenic cellular material (nucleic acids, lipids, and certain cellular proteins) and preserving the structure of ECM (collagen, elastin, GAGs, and growth factors), such that it provides an optimal substrate for regeneration of functional host tissues. In contrast to thinner tissues such as intestinal submucosa, the thickness and complexity of dermis requires more intensive mechanical and chemical methods to achieve adequate decellularization.8 These harsher processing methods have been shown to result in variable degradation of extracellular matrix structure as well as reduction in GAG and growth factor content. However, failure of a decellularization method to remove major histocompatibility complex (MHC) antigens to below a critical level will result in a failure of matrix remodeling and incorporation.7 A variety of decellularization methods have been described, including mechanical, chemical, enzymatic, and detergent-based protocols, and often a combination of these.1 The optimal decellularization protocol depends on tissue type, thickness, shape, cell density, and matrix density and thus will vary by tissue of origin and reconstructive purposes.1 While decellarization protocols of particular commercially available ADMs are proprietary, they presumably involve some combination of the above-reported methods.
3D In Vitro/Ex Vivo Systems
Anthony J. Hickey, Sandro R.P. da Rocha in Pharmaceutical Inhalation Aerosol Technology, 2019
Decellularization of tissues was first pioneered in the late 1970s (Hjelle et al. 1979) with the aim of isolating tissue-specific basement membrane. Over the years, several key groups, such as the Badylak and Ott laboratories, have made great strides in the development of decellularization methods that can extend to xenograph or allograph scaffolds and many different organs. The goal of this research is to develop a tissue-specific scaffold for cell growth and differentiation of a patient’s cells. Once cells have been removed, the extracellular matrix that is left behind can be used as a scaffold for tissue engineering by providing the architecture of the native organ. Decellularized tissues do not require the preservation of the cellular function and therefore can be frozen before use or taken from donors unsuitable for transplant. This creates a less demanding model, in terms of sterility and controlled environmental conditions, compared to an ex vivo perfused model. It is important to note that this technology can be costly and usually requires further methods, such as recellularization, to make this a useful experimental tool.
The decellularized ovary as a potential scaffold for maturation of preantral ovarian follicles of prepubertal mice
Published in Systems Biology in Reproductive Medicine, 2021
Sanaz Alaee, Raheleh Asadollahpour, Abasalt Hosseinzadeh Colagar, Tahereh Talaei-Khozani
The histochemical data showed that the integrity of the ovarian tissue was well preserved after decellularization. Both H&E and Hoechst staining illustrated that the cells were absent in the decellularized ovary (Figure 2). The quantitative DNA assay displayed a statistically significant decline in the DNA content of the decellularized ovaries compared to that of the intact ovaries (21.45 ± 3.36 ng/mg versus 414.20 ± 31.90 ng/mg dry tissue weight; P < 0.001), confirming efficient cell removal (Figure 3A). Staining by Masson’s trichrome showed that collagen fibers were preserved in the ovaries after decellularization, with a distribution similar to that of the normal tissue (Figure 2). Performing Alcian blue staining to identify GAG content revealed that it partially remained after decellularization (Figure 2). Overall, histochemical staining showed that the decellularization procedure kept the main part of the ECM while efficiently removing the cells.
Surgical Models to Explore Acellular Liver Scaffold Transplantation: Step-by-Step
Published in Organogenesis, 2020
Marlon L. Dias, Cíntia M. P. Batista, Victor J. K. Secomandi, Alexandre C. Silva, Victoria R. S. Monteiro, Lanuza A. Faccioli, Regina C. S. Goldenberg
Chronic liver diseases affect more than 500 million people worldwide.1 Currently, transplantation is the only treatment available for liver failure. However, problems such as organ availability, graft viability and immune rejection create a long waiting list. Tissue engineering appears as a promising alternative with the production of acellular organs and tissues from the extracellular matrix (ECM) of potential use in Regenerative Medicine. ECM is a complex and dynamic environment characterized by biophysical, mechanical and biochemical properties specific to each organ. Acellular scaffolds can be produced by decellularization techniques.2 The decellularization process removes all cell content of an organ or tissue, leaving only the components of the extracellular matrix specific to the organ or tissue such as collagen, fibronectin, laminin and others.3 The technique of decellularization has already been used for several organs such as heart, lung, kidney, placenta and liver, as well as tissues such as skin, intestinal mucosa, heart valve, among others.4-11 Some studies have shown that these acellular organs can be transplanted in animals.12, 13 Unfortunately, regarding acellular liver transplantation several aspects have not yet been reported, such as endogenous ECM potency to cell recruitment in vivo, acellular liver graft long-term function and contribution to recipient rat liver functions post-transplantation.14
Airway reconstruction using decellularized aortic xenografts in a dog model
Published in Organogenesis, 2020
Shao-Fei Cheng, Song Wu, Qian-Ping Li, Hong-Yang Sang, Zheng-Yang Fan
Experimental evidence indicates that a decellularized biologic material composed of ECM matrix provide a popular scaffold for functional recipient cells.25 However, the method of decellularization closely affects the biochemical composition, tissue ultrastructure, and mechanical behavior of the remaining ECM scaffold, which is important for the subsequent regeneration and adhesion of host cells on the graft.15,26 Decellularized aortic graft by sodium dodecylsulfate (SDS) treatment reportedly leads to a complete loss of cellular structures from the three layers of the arterial wall and only conservation of the main component of the ECM. However, that decellularized aortic graft failed to transform into a new tracheal epithelium.27 Study has shown that fibroblasts are important in activating epithelial cell proliferation and migration when co-cultured tracheal epithelial cells with fibroblasts.28 In our study, aortic grafts were decellularized with method including detergent and enzyme extraction which only removed the endothelial cell of the arterial wall and better conserved the majority of arterial wall including fibroblasts, muscle cell layer, and ECM. The results of H&E staining and SEM revealed regenerated epithelium and cilia on the reconstructed luminal surface at 6 months after implantation. Whether re-epithelialization after the implantation of decellularized bovine aortic graft is caused by conserved fibroblasts is needed further investigation.
Related Knowledge Centers
- Antibody
- Artificial Organ
- Biomaterial
- Tissue
- Cellular Differentiation
- Immune System
- Extracellular Matrix
- Tissue Engineering
- Antigen
- Progenitor Cell