Acellular human glans extracellular matrix as a scaffold for tissue engineering: in vitro cell support and biocompatibility

Rabbit thyroid extracellular matrix as a 3D bioscaffold for thyroid bioengineering: a preliminary in vitro study

BACKGROUND

Advances in regenerative medicine technologies have been strongly proposed in the management of thyroid diseases. Mechanistically, the adoption of thyroid bioengineering requires a scaffold that shares a similar three-dimensional (3D) space structure, biomechanical properties, protein component, and cytokines to the native extracellular matrix (ECM).

METHODS

24 male New Zealand white rabbits were used in this experimental study. The rabbit thyroid glands were decellularized by immersion/agitation decellularization protocol. The 3D thyroid decellularization scaffolds were tested with histological and immunostaining analyses, scanning electron microscopy, DNA quantification, mechanical properties test, cytokine assay and cytotoxicity assays. Meanwhile, the decellularization scaffold were seeded with human thyroid follicular cells, cell proliferation and thyroid peroxidase were determined to explore the biocompatibility in vitro.

RESULTS

Notably, through the imaging studies, it was distinctly evident that our protocol intervention minimized cellular materials and maintained the 3D spatial structure, biomechanical properties, ECM composition, and biologic cytokine. Consequently, the decellularization scaffold was seeded with human thyroid follicular cells, thus strongly revealing its potential in reinforcing cell adhesion, proliferation, and preserve important protein expression.

CONCLUSIONS

The adoption of our protocol to generate a decellularized thyroid scaffold can potentially be utilized in transplantation to manage thyroid diseases through thyroid bioengineering.

Complete Human Penile Scaffold for Composite Tissue Engineering: Organ Decellularization and Characterization

Reconstruction for total penile defects presents unique challenges due to its anatomical and functional complexity. Standard methods suffer from high complication rates and poor functional outcomes. In this work we have developed the first protocol for decellularizing whole-organ human penile specimens for total penile tissue engineering. The use of a hybrid decellularization scheme combining micro-arterial perfusion, urethral catheter perfusion and external diffusion enabled the creation of a full-size scaffold with removal of immunogenic components. Decellularization was complete as assessed by H&E and immunohistochemistry, while quantification of residual DNA showed acceptably low levels (<50 ng/mg). An intact ECM was maintained with histologic architecture preservation on H&E and SEM as well as preservation of key proteins such as collagen-1, laminin and fibronectin and retention of growth factors VEGF (45%), EGF (57%) and TGF-beta1 (42%) on ELISA. Post-decellularization patency of the cavernosal arteries for future use in reseeding was demonstrated. Scaffold biocompatibility was evaluated using human adipose-derived stromal vascular cells. Live/Dead stains showed the scaffold successfully supported cell survival and expansion. Influence on cellular behavior was seen with significantly higher expression of VWF, COL1, SM22 and Desmin as compared to cell monolayer. Preliminary evidence for regional tropism was also seen, with formation of microtubules and increased endothelial marker expression in the cavernosa. This report of successful decellularization of the complete human phallus is an initial step towards developing a tissue engineered human penile scaffold with potential for more successfully restoring cosmetic, urinary and sexual function after complete penile loss.

Tissue-Engineered Grafts from Human Decellularized Extracellular Matrices: A Systematic Review and Future Perspectives

Tissue engineering and regenerative medicine involve many different artificial and biologic materials, frequently integrated in composite scaffolds, which can be repopulated with various cell types. One of the most promising scaffolds is decellularized allogeneic extracellular matrix (ECM) then recellularized by autologous or stem cells, in order to develop fully personalized clinical approaches. Decellularization protocols have to efficiently remove immunogenic cellular materials, maintaining the nonimmunogenic ECM, which is endowed with specific inductive/differentiating actions due to its architecture and bioactive factors. In the present paper, we review the available literature about the development of grafts from decellularized human tissues/organs. Human tissues may be obtained not only from surgery but also from cadavers, suggesting possible development of Human Tissue BioBanks from body donation programs. Many human tissues/organs have been decellularized for tissue engineering purposes, such as cartilage, bone, skeletal muscle, tendons, adipose tissue, heart, vessels, lung, dental pulp, intestine, liver, pancreas, kidney, gonads, uterus, childbirth products, cornea, and peripheral nerves. In vitro recellularizations have been reported with various cell types and procedures (seeding, injection, and perfusion). Conversely, studies about in vivo behaviour are poorly represented. Actually, the future challenge will be the development of human grafts to be implanted fully restored in all their structural/functional aspects.

Minocycline enhances the mesenchymal stromal/stem cell pro-healing phenotype in triple antimicrobial-loaded hydrogels

Mesenchymal stromal/stem cells (MSCs) have demonstrated pro-healing properties including an anti-inflammatory cytokine profile and the promotion of angiogenesis via expression of growth factors in pre-clinical models. MSCs encapsulated in poly(ethylene glycol) diacrylate (PEGdA) and thiolated gelatin poly(ethylene glycol) (Gel-PEG-Cys) crosslinked hydrogels have led to controlled cellular presentation at wound sites with favorable wound healing outcomes. However, the therapeutic potential of MSC-loaded hydrogels may be limited by non-specific protein adsorption on the delivery matrix that could facilitate the initial adhesion of microorganisms and subsequent virulent biofilm formation. Antimicrobials loaded concurrently in the hydrogels with MSCs could reduce microbial bioburden and promote healing, but the antimicrobial effect on the MSC wound healing capacity and the antibacterial efficacy of the hydrogels is unknown. We demonstrate that minocycline specifically induces a favorable change in MSC migration capacity, proliferation, gene expression, extracellular matrix (ECM) attachment, and adhesion molecule and growth factor release with subsequent increased angiogenesis. We then demonstrate that hydrogels loaded with MSCs, minocycline, vancomycin, and linezolid can significantly decrease bacterial bioburden. Our study suggests that minocycline can serve as a dual mechanism for the regenerative capacity of MSCs and the reduction of bioburden in triple antimicrobial-loaded hydrogels.

STATEMENT OF SIGNIFICANCE

Wound healing is a complex biological process that can be hindered by bacterial infection, excessive inflammation, and inadequate microvasculature. In this study, we develop a new formulation of poly(ethylene glycol) diacrylate and thiolated gelatin poly(ethylene glycol) crosslinked hydrogels loaded with minocycline, vancomycin, linezolid, and mesenchymal stromal/stem cells that induces a favorable wound healing phenotype in mesenchymal stromal/stem cells and prevents bacterial bioburden on the hydrogel. This combinatorial approach to biomaterial development has the potential to impact wound healing for contaminated full thickness cutaneous wounds.

Cogels of Hyaluronic Acid and Acellular Matrix for Cultivation of Adipose-Derived Stem Cells: Potential Application for Vocal Fold Tissue Engineering

Stem cells based tissue engineering has been one of the potential promising therapies in the research on the repair of tissue diseases including the vocal fold. Decellularized extracellular matrix (DCM) as a promising scaffold has be used widely in tissue engineering; however, it remained to be an important issue in vocal fold regeneration. Here, we applied the hydrogels (hyaluronic acid [HA], HA-collagen [HA-Col], and HA-DCM) to determine the effects of hydrogel on the growth and differentiation of human adipose-derived stem cells (hADSCs) into superficial lamina propria fibroblasts. hADSCs were isolated and characterized by fluorescence-activated cell sorting. The results indicated that HA-DCM hydrogel enhanced cell proliferation and prolonged cell morphology significantly compared to HA and HA-Col hydrogel. Importantly, the differentiation of hADSCs into fibroblasts was also promoted by cogels of HA-Col and HA-DCM significantly. The differentiation of hADSCs towards superficial lamina propria fibroblasts was accelerated by the secretion of HGF, IL-8, and VEGF, the decorin and elastin expression, and the synthesis of chondroitin sulfate significantly. Therefore, the cogel of HA-DCM hydrogel was shown to be outstanding in apparent stimulation of hADSCs proliferation and differentiation to vocal fold fibroblasts through secretion of important growth factors and synthesis of extracellular matrix.