Decellularized Adipose Tissue Research Articles

Challenges in Application: Gelation Strategies of DAT-Based Hydrogel Scaffolds.

Decellularized adipose tissue (DAT) has great clinical applicability, owing to its abundant source material, natural extracellular matrix microenvironment, and nonimmunogenic attributes, rendering it a versatile resource in the realm of tissue engineering. However, practical implementations are confronted with multifarious limitations. Among these, the selection of an appropriate gelation strategy serves as the foundation for adapting to diverse clinical contexts. The cross-linking strategies under varying physical or chemical conditions exert profound influences on the ultimate morphology and therapeutic efficacy of DAT. This review sums up the processes of DAT decellularization and subsequent gelation, with a specific emphasis on the diverse gelation strategies employed in recent experimental applications of DAT. The review expounds upon methodologies, underlying principles, and clinical implications of different gelation strategies, aiming to offer insights and inspiration for the application of DAT in tissue engineering and advance research for tissue engineering scaffold development.

High Throughput Bioprinting Using Decellularized Adipose Tissue-Based Hydrogels for 3D Breast Cancer Modeling.

3D bioprinting allows rapid automated fabrication and can be applied for high throughput generation of biomimetic constructs for in vitro drug screening. Decellularized extracellular matrix (dECM) hydrogel is a popular biomaterial choice for tissue engineering and studying carcinogenesis as a tumor microenvironmental mimetic. This study proposes a method for high throughput bioprinting with decellularized adipose tissue (DAT) based hydrogels for 3D breast cancer modeling. A comparative analysis of decellularization protocol using detergent-based and detergent-free decellularization methods for caprine-origin adipose tissue is performed, and the efficacy of dECM hydrogel for 3D cancer modeling is assessed. Histological, biochemical, morphological, and biological characterization and analysis showcase the cytocompatibility of DAT hydrogel. The rheological property of DAT hydrogel and printing process optimization is assessed to select a bioprinting window to attain 3D breast cancer models. The bioprinted tissues are characterized for cellular viability and tumor cell-matrix interactions. Additionally, an approach for breast cancer modeling is shown by performing rapid high throughput bioprinting in a 96-well plate format, and in vitro drug screening using 5-fluorouracil is performed on 3D bioprinted microtumors. The results of this study suggest that high throughput bioprinting of cancer models can potentially have downstream clinical applications like multi-drug screening platforms and personalized disease models.

Adipose tissue reconstruction facilitated with low immunogenicity decellularized adipose tissue scaffolds.

There is currently an urgent need to develop engineered scaffolds to support new adipose tissue formation and facilitate long-term maintenance of function and defect repair to further generate prospective bioactive filler materials capable of fulfilling surgical needs. Herein, adipose regeneration methods were optimized and decellularized adipose tissue (DAT) scaffolds with good biocompatibility were fabricated. Adipose-like tissues were reconstructed using the DAT and 3T3-L1 preadipocytes, which have certain differentiation potential, and the regenerative effects of the engineered adipose tissuesin vitroandin vivowere explored. The method improved the efficiency of adipose removal from tissues, and significantly shortened the time for degreasing. Thus, the DAT not only provided a suitable space for cell growth but also promoted the proliferation, migration, and differentiation of preadipocytes within it. Following implantation of the constructed adipose tissuesin vivo, the DAT showed gradual degradation and integration with surrounding tissues, accompanied by the generation of new adipose tissue analogs. Overall, the combination of adipose-derived extracellular matrix and preadipocytes for adipose tissue reconstruction will be of benefit in the artificial construction of biomimetic implant structures for adipose tissue reconstruction, providing a practical guideline for the initial integration of adipose tissue engineering into clinical medicine.

Combination of Adipose-Derived Stromal/Stem Cells and Decellularized Adipose Tissue Hydrogel for Osteogenic Applications.

Adipose-derived stromal/stem cells (ASCs) and decellularized adipose tissue (DAT) are adipose tissue products obtained from individuals undergoing fat removal procedures like liposuction, lipectomy, or breast reduction. DAT hydrogel is prepared by removing the cells from the adipose tissue and digesting it to form a liquid material that forms a gel at physiological temperature. ASCs seeded on DAT have displayed osteogenic potential in vitro and in animal models of bone defects. Herein, we describe the methods for preparing DAT hydrogel, ASC seeding in DAT hydrogel, osteogenic differentiation of ASCs, creation of critical-sized femur defect model in mice, its treatment with ASC-DAT hydrogel, and analyses.

Manufacturing of a Human Adipose-Derived Hydrogel.

Hydrogels are considered a viable in vitro alternative to monolayer cultures. They provide quintessential characteristics for in vitro studies including biocompatibility, biodegradability, viscoelasticity, hydrophilicity, and low toxicity. Furthermore, many provide necessary extracellular matrix proteins and architecture to support cell growth, proliferation, differentiation, and migration. Synthetic and natural polymer-derived hydrogels both demonstrate positive qualities; however, natural hydrogels have attracted great interest due to their clinical relevancy. In particular, decellularized tissue-derived hydrogels have been identified as a significant resource for tissue engineering applications by mimicking the composition and architecture of their tissue of origin.The use of adipose tissue as a hydrogel has become more prevalent because of limitless resources and accessibility of the tissue itself. Obatala Sciences has established a manufacturing protocol for human decellularized adipose tissue (hDAT) using a series of steps including mechanical disruption, chemical disruption with N-Lauroylsarcosine, and enzymatic digestion with pepsin and hydrochloric acid.

Three-Dimensional Bioprinting in Soft Tissue Engineering for Plastic and Reconstructive Surgery.

Skeletal muscle tissue engineering (TE) and adipose tissue engineering have undergone significant progress in recent years. This review focuses on the key findings in these areas, particularly highlighting the integration of 3D bioprinting techniques to overcome challenges and enhance tissue regeneration. In skeletal muscle TE, 3D bioprinting enables the precise replication of muscle architecture. This addresses the need for the parallel alignment of cells and proper innervation. Satellite cells (SCs) and mesenchymal stem cells (MSCs) have been utilized, along with co-cultivation strategies for vascularization and innervation. Therefore, various printing methods and materials, including decellularized extracellular matrix (dECM), have been explored. Similarly, in adipose tissue engineering, 3D bioprinting has been employed to overcome the challenge of vascularization; addressing this challenge is vital for graft survival. Decellularized adipose tissue and biomimetic scaffolds have been used as biological inks, along with adipose-derived stem cells (ADSCs), to enhance graft survival. The integration of dECM and alginate bioinks has demonstrated improved adipocyte maturation and differentiation. These findings highlight the potential of 3D bioprinting techniques in skeletal muscle and adipose tissue engineering. By integrating specific cell types, biomaterials, and printing methods, significant progress has been made in tissue regeneration. However, challenges such as fabricating larger constructs, translating findings to human models, and obtaining regulatory approvals for cellular therapies remain to be addressed. Nonetheless, these advancements underscore the transformative impact of 3D bioprinting in tissue engineering research and its potential for future clinical applications.

Combining decellularized adipose tissue with decellularized adventitia extravascular matrix or small intestinal submucosa matrix for the construction of vascularized tissue-engineered adipose

Adipose tissue is an endocrine organ. It serves many important functions, such as energy storage, hormones secretion, and providing insulation, cushioning and aesthetics to the body etc. Adipose tissue engineering offers a promising treatment for soft tissue defects. Early adipose tissue production and long-term survival are closely associated with angiogenesis. Decellularized matrix has a natural ECM (extracellular matrix) component, good biocompatibility, and low immunogenicity. Therefore, in this study, the injectable composite hydrogels were developed to construct vascularized tissue-engineered adipose by using the pro-angiogenic effects of aortic adventitia extravascular matrix (Adv) or small intestinal submucosa (SIS), and the pro-adipogenic effects of decellularized adipose tissue (DAT). The composite hydrogels were cross-linked by genipin. The adipogenic and angiogenic abilities of composite hydrogels were investigated in vitro, and in a rat dorsal subcutaneous implant model. The results showed that DAT and SIS or Adv 1:1 composite hydrogel promoted the migration and tube formation of endothelial cells. Furthermore, DAT and SIS or Adv 1:1 composite hydrogel enhanced adipogenic differentiation of adipose-derived mesenchymal stem cells (ASCs) through activation of PPARγ and C/EBPα. The in vivo studies further demonstrated that DAT with SIS or Adv in a 1:1 ratio also significantly promoted adipogenesis and angiogenesis. In addition, DAT with SIS or Adv in a 1:1 ratio hydrogel recruited macrophage population with enhanced M2-type macrophage polarization, suggesting a positive effect of inflammatory response on angiogenesis. In conclusion, these data suggest that the composite hydrogels of DAT with SIS or Adv in 1:1 ratio have apparent pro-adiogenic and angiogenic abilities, thus providing a promising cell-free tissue engineering biomaterial with broad clinical applications. Statement of significanceDecellularized adipose tissue (DAT) has emerged as an important biomaterial in adipose tissue regeneration. Early adipose tissue production and long-term survival is tightly related to the angiogenesis. The revascularization of the DAT is a key issue that needs to be solved in adipose regeneration. In this study, the injectable composite hydrogels were developed by using DAT with Adv (aortic adventitia extravascular matrix) or SIS (small intestinal submucosa) in different ratio. We demonstrated that the combination of DAT with SIS or Adv in 1:1 ratio effectively improved the proliferation of adipose stem cells and endothelial cells, and promoted greater adipose regeneration and tissue vascularization as compared to the DAT scaffold. This study provides the potential biomaterial for clinical soft tissue regeneration.

Insulin modified Decellularized Adipose Tissue/Tremella Polysaccharide hydrogel loaded with ADSCs for skin wound healing

Full-thickness skin wounds still represent a challenge for clinical treatment. Adipose-derived stem cells (ADSCs) therapy is a promising approach to achieve efficient healing in skin wounds. The excellent cell scaffold can promote proliferation, differentiation and paracrine of ADSCs in wound microenvironment, and is a key factor in ADSCs application. Herein, we first prepared the composite hydrogel with decellularized adipose tissue (DAT) and tremella polysaccharide (TPS), and loaded insulin (INS) into the DAT/TPS composite hydrogel (DAT/TPS-gel) to fabricate an efficient carrier for ADSCs in treating skin wound. Our study showed that INS modified DAT/TPS-gel (INS-DAT/TPS-gel) can promote the proliferation, differentiation and paracrine of ADSCs. INS-DAT/TPS-gel laden with ADSCs (ADSCs/INS-DAT/TPS-gel) effectively facilitated the skin wound healing in SD rats. These findings indicated that INS-DAT/TPS-gel was an effective scaffold for ADSCs transplantation, and ADSCs/INS-DAT/TPS-gel provides a potential strategy for the treatment of skin wounds.

Engineered nanovesicles from stromal vascular fraction promote angiogenesis and adipogenesis inside decellularized adipose tissue through encapsulating growth factors

Acellular matrix is a commonly used biomaterial in the field of biomedical engineering and revascularization is the key process to affect the effect of acellular matrix on tissue regeneration. The application of bioactive factors related to angiogenesis has been popular in the regulation of revascularization, but the immune system clearance, uncontrollable systemic reactions, and other factors make this method face challenges. Recent reports showed that engineered cells into nanovesicles can reorganize cell membranes and encapsulate cellular active factors, extending the in vitro preservation of cytokines. However, the problems of exogenous biological contamination and tumorigenicity restricted the clinical transformation and wide application of this method. Here, we for the first time engineer stromal vascular fraction (SVF) which is extracted from fat into nanovesicles (SVF-EVs) for angiogenesis in the acellular matrix. SVF-EVs not only promote the migration of vascular endothelial cells in vitro, but also facilitate the lipogenic differentiation of mesenchymal stem cells. In vivo, SVF-EVs enhanced the retention of decellularized adipose tissue after transplanting to the subcutaneous area of nude mice. Immunofluorescence staining further showed that SVF-EVs promoted the formation of vascular networks with large lumen diameter in the grafted acellular matrix, accompanied by adipocyte regeneration peripherally. These findings reveal that SVF-EVs can be a viable method for accelerating revascularization in acellular matrix, and this process of squeezing tissue into nanovesicles shows the potential for rapid clinical transformation.

Adjusting the stiffness of a cell-free hydrogel system based on tissue-specific extracellular matrix to optimize adipose tissue regeneration.

Large-area soft tissue defects are challenging to reconstruct. Clinical treatment methods are hampered by problems associated with injury to the donor site and the requirement for multiple surgical procedures. Although the advent of decellularized adipose tissue (DAT) offers a new solution to these problems, optimal tissue regeneration efficiency cannot be achieved because the stiffness of DAT cannot be altered in vivo by adjusting its concentration. This study aimed to improve the efficiency of adipose regeneration by physically altering the stiffness of DAT to better repair large-volume soft tissue defects. In this study, we formed three different cell-free hydrogel systems by physically cross-linking DAT with different concentrations of methyl cellulose (MC; 0.05, 0.075 and 0.10g/ml). The stiffness of the cell-free hydrogel system could be regulated by altering the concentration of MC, and all three cell-free hydrogel systems were injectable and moldable. Subsequently, the cell-free hydrogel systems were grafted on the backs of nude mice. Histological, immunofluorescence and gene expression analyses of adipogenesis of the grafts were performed on days 3, 7, 10, 14, 21 and 30. The migration of adipose-derived stem cells (ASCs) and vascularization were higher in the 0.10g/ml group than in the 0.05 and 0.075g/ml groups on days 7, 14 and 30. Notably, on days 7, 14 and 30, the adipogenesis of ASCs and adipose regeneration were significantly higher in the 0.075g/ml group than in the 0.05g/ml group (p < 0.01 or p < 0.001) and 0.10g/ml group (p < 0.05 or p < 0.001). Adjusting the stiffness of DAT via physical cross-linking with MC can effectively promote adipose regeneration, which is of great significance to the development of methods for the effective repair and reconstruction of large-volume soft tissue defects.

Pre-clinical evaluation of thermosensitive decellularized adipose tissue/platelet-rich plasma interpenetrating polymer network hydrogel for wound healing.

Wound healing remains a challenge worldwide, and an ideal wound dressing that promotes healing is urgently needed. In this study, we developed a thermosensitive injectable hydrogel known as the thermosensitive decellularized adipose tissue/platelet-rich plasma interpenetrating polymer network (t-DPI) hydrogel based on decellularized adipose tissue (DAT) and temperature-controlled platelet-rich plasma (t-PRP). Abundant platelets, growth factors (GFs), and bioactive substances from the decellularized extracellular matrix (dECM) in the t-DPI hydrogel had positive effects on wound healing. The morphology, thermosensitivity, and GFs release properties of the t-DPI hydrogel were studied. In vitro, the t-DPI hydrogel showed ideal cytocompatibility and the abilities to promote the proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs). Moreover, M2 macrophage polarization was enhanced after treated with t-DPI hydrogel. In vivo, the t-DPI hydrogel notably accelerated the full-thickness wound healing. The positive role of the t-DPI hydrogel on pro-angiogenesis, macrophage polarization and collagen deposition were validated in the nude mouse full-thickness skin defect model. In addition, the clinical application potential was confirmed using a pre-clinical porcine full-thickness wound model. Overall, this study demonstrated that the t-DPI hydrogel achieves fast and ideal wound healing in full-thickness wound defects and provides a potential clinical treatment strategy.

Analysis of DAT Combined with the VSD Technique in Wound Repair of Rats and Its Effect on Inflammatory Factors.

The clinical efficacy of decellularized adipose tissue (DAT) combined with vacuum sealing drainage (VSD) in the treatment of wound healing in rats is investigated, and the changes of inflammatory factors are analyzed. The tissue defect model of SD (Sprague-Dawley) rats is established and divided into the combined group (n = 12) and the control group (n = 12) according to different treatment methods. The control group is treated with a single VSD technique, and the combined group is treated with DAT on the basis of the control group. The wound healing time of the two groups is observed. Wound tissue is collected 1 day, 10 days, 20 days, and 30 days after treatment, and neutrophil infiltration is observed by HE (hematoxylin-eosin) staining. The expression changes of IL-6 and IL-13 at each time point before and after treatment are compared. Histological observation shows that the cell infiltration is reduced in both groups, and the wound repair in the combined group is better than that in the control group. The experimental results show that the DAT combined with the VSD technique can further speed up wound healing and reduce inflammation in rats.

Enhanced Adipogenic Differentiation of Human Dental Pulp Stem Cells in Enzymatically Decellularized Adipose Tissue Solid Foams.

Simple SummaryObesity shortens human lifespan and represents one of the most important public health problems causing significant economic and societal consequences worldwide. However, the current development of physiological human 3D adipose tissue models for in vitro research on preclinical personalized medicine is limited and expensive. Here, we designed, produced, and characterized 3D solid foams using a mixture of bovine collagen I and decellularized human adipose tissue to serve as a 3D matrix mimicking in vivo adipose microenvironment for cell culture purposes. Furthermore, we sought to validate its compatibility for the culture of human mesenchymal stem cells isolated from the dental pulp. We demonstrated that 3D solid foams are able to integrate the stem cells from the dental pulp and provide the appropriate cues to differentiate them into mature adipocytes. The results represent an advance of in vitro 3D models using a human extracellular matrix derived material for future personalized stem cell therapies.Engineered 3D human adipose tissue models and the development of physiological human 3D in vitro models to test new therapeutic compounds and advance in the study of pathophysiological mechanisms of disease is still technically challenging and expensive. To reduce costs and develop new technologies to study human adipogenesis and stem cell differentiation in a controlled in vitro system, here we report the design, characterization, and validation of extracellular matrix (ECM)-based materials of decellularized human adipose tissue (hDAT) or bovine collagen-I (bCOL-I) for 3D adipogenic stem cell culture. We aimed at recapitulating the dynamics, composition, and structure of the native ECM to optimize the adipogenic differentiation of human mesenchymal stem cells. hDAT was obtained by a two-enzymatic step decellularization protocol and post-processed by freeze-drying to produce 3D solid foams. These solid foams were employed either as pure hDAT, or combined with bCOL-I in a 3:1 proportion, to recreate a microenvironment compatible with stem cell survival and differentiation. We sought to investigate the effect of the adipogenic inductive extracellular 3D-microenvironment on human multipotent dental pulp stem cells (hDPSCs). We found that solid foams supported hDPSC viability and proliferation. Incubation of hDPSCs with adipogenic medium in hDAT-based solid foams increased the expression of mature adipocyte LPL and c/EBP gene markers as determined by RT-qPCR, with respect to bCOL-I solid foams. Moreover, hDPSC capability to differentiate towards adipocytes was assessed by PPAR-γ immunostaining and Oil-red lipid droplet staining. We found out that both hDAT and mixed 3:1 hDAT-COL-I solid foams could support adipogenesis in 3D-hDPSC stem cell cultures significantly more efficiently than solid foams of bCOL-I, opening the possibility to obtain hDAT-based solid foams with customized properties. The combination of human-derived ECM biomaterials with synthetic proteins can, thus, be envisaged to reduce fabrication costs, thus facilitating the widespread use of autologous stem cells and biomaterials for personalized medicine.

Decellularized adipose tissue matrix-coated and simvastatin-loaded hydroxyapatite microspheres for bone regeneration.

Simvastatin (SIM)-loaded and human decellularized adipose tissue (DAT)-coated porous hydroxyapatite (HAp) microspheres were developed for the first time to investigate their potential on bone regeneration. Microspheres were loaded with SIM and then coated with DAT for modifying SIM release and improving their biological response. HAp microspheres were prepared by water-in-oil emulsion method using camphene (C10 H16 ) as porogen followed by camphene removal by freeze-drying and sintering at 1200°C for 3 h. Sintered HAp microspheres with an average particle size of ~400 µm were porous and spherical in shape. Microspheres were incubated with 1, 2.5, and 5 mg/ml SIM stock solutions for drug loading, and drug loading was determined as 7.5 ± 0.79, 20.41 ± 1.93, and 46.26 ± 0.29 µg SIM/mg microspheres, respectively. SIM loading increased with the increase of the initial SIM loading amount. Faster SIMrelease was observed in DAT-coated microspheres compared to bare counterparts. Higher SaoS-2 cell attachment and proliferation were observed on DAT-coated microspheres. Significantly higher alkaline phosphatase activity of SaoS-2 cells was observed on DAT-coated microspheres containing 0.01 mg/ml SIM than all other groups (p < 0.01). DAT-coated microspheres loaded with SIM at low doses hold promise for bone tissue engineering applications.

Additively manufactured macroporous chambers facilitate large volume soft tissue regeneration from adipose-derived extracellular matrix

Breast tissue engineering is a promising alternative intervention for breast reconstruction. Due to their low immunogenicity and well-preserved adipogenic microenvironment, decellularized adipose tissue (DAT) can potentially regenerate adipose tissue in vivo. However, the volume of adipose tissue regenerated from DAT can hardly satisfy the demand for breast reconstruction. Tissue engineering chamber (TEC) is an effective technique for generation of large adipose tissue volumes. However, TEC applications necessitate reoperation to remove non-degradable plastic chambers and harvest autologous tissue flaps, which prolongs the operation time and causes potential damage to donor sites. We improved the TEC strategy by combining bioresorbable polycaprolactone (PCL) chambers and decellularized adipose tissues (DAT). A miniaturized porous PCL chamber was fabricated based on scaling differences between human and rabbit chests, and basic fibroblast growth factor (bFGF)-loaded DAT successfully prepared. In rabbit models, a highly vascularized adipose tissue that nearly filled up the PCL chamber (5 mL) was generated de novo from 0.5 mL bFGF-loaded DAT. The newly formed tissue had significantly high expressions of adipogenic genes, compared to the endogenous adipose tissue. The concept described here can be exploited for breast tissue engineering. Statement of significanceDecellularized adipose tissue (DAT), which provides infiltrated cells adipogenic microenvironment, can potentially regenerate adipose tissue in vivo. Nevertheless, the volume of regenerated adipose tissue is insufficient to repair large sized tissue defect. Tissue engineering chamber (TEC) could provide a protective space for in situ regeneration of large volume tissue. Herein, a new strategy by combining biodegradable polycaprolactone chambers and basic fibroblast growth factor-loaded decellularized adipose tissue is proposed. In rabbit model, newly formed adipose tissue regenerated from DAT successfully filled the dome shaped chamber with ten folds higher volume than DAT, which is proportionally similar to women breast. This work highlighted the importance of adipogenic microenvironment and protective space for adipose tissue regeneration.

Decellularized Human Adipose Tissue as an Alternative Graft Material for Bone Regeneration.

Tissue engineering approaches to treat damaged bone include various tissue transplants such as autologous, allogeneic, and xenografts. Artificial materials have been widely introduced to meet the demand for graft materials, but insufficiency in supply is still not resolved. In this study, human adipose tissue, easily obtained from the human body, was harvested, and the tissue was decellularized to fabricate a decellularized human adipose tissue matrix (DM) as an alternative graft material. Human adipose tissue was obtained via liposuction. The obtained fresh adipose tissue sample was cut into pieces then put into decellularization solution (1% antibiotic-antimycotic solution and 1% phenylmethanesulphonyl fluoride). Lipids were further removed via treatment in isopropanol. The sample was then subjected to another enzymatic digestion and lipid removal processes. The obtained decellularized adipose tissue matrix was lyophilized to form a graft material in disc shape. Decellularization was confirmed by nuclear staining methods and detection of RNA and DNA via PCR. Bone morphogenetic protein 2 (BMP2)-loaded DM showed the ability to form new bone tissue when implanted in subcutaneous tissue. In recovery of a mouse calvarial defect model, BMP2-loaded DM exhibited similar levels of bone tissue regeneration efficiency compared with a well-defined commercial product, BMP2-loaded CollaCote®. The DM developed in this study is expected to address the problem of insufficient supply of graft materials and contribute to the treatment of bone defects of critical size as an alternative bone graft material with preserved extracellular matrix components.

Three-dimensional cultivation of human adipose-derived stem cells with human decellularized adipose tissue matrix scaffold promotes diabetic wound healing

Diabetic wounds are a worldwide health problem, with increasing morbidity and risk of amputation. This study investigated a novel application of a human decellularized adipose tissue matrix (hDAM) as a natural 3D scaffold for delivering human adipose-derived stem cells (hASCs) to diabetic wounds. The porous structure, ability to preserve extracellular matrix components, and convenient storage conditions of decellularized hDAM make it a potential clinical wound dressing material. The hASCs cultured in the hDAM scaffold exhibited a fibroblast-like morphology and more evenly distributed cells on both the surface and inside the porous structure of the hDAM scaffold. In addition, the biocompatibility of hDAM enhanced the hASCs proliferation, maintenance of the stemness properties, and release of angiogenic cytokines compared to those under standard culture conditions. Moreover, cell suspensions derived from hASCs cultured in hDAM scaffolds promoted the proliferation and migration of human umbilical vascular endothelial cells, indicating its potential effect in promoting angiogenesis. Furthermore, the potential clinical therapeutic efficacy of the hASC-hDAM composite for diabetic wound healing was evaluated using a full-thickness wound model in diabetic mice. Diabetic rats treated with the hASCs-seeded hDAM scaffold displayed enhanced wound healing efficiency, including an improved blood perfusion volume for wounds, reduced number of inflammatory cells, and enhanced epithelization. This study demonstrated that the 3D model that combined hASCs and an hDAM could accelerate wound healing and might hold potential for clinical application to enhance diabetic wound healing and regeneration.

Construction of adipose tissue using a silica expander capsule and cell sheet-assembled of decellularized adipose tissue

Delayed neovascularization and unstable adipose formation are major confounding factors in adipose tissue engineering. A system using decellularized adipose tissue (DAT), adipose-derived stem cells (ADSCs), and human umbilical vein endothelial cells (HUVECs) has been preliminarily studied, but it requires optimization, as adipogenic and angiogenic capabilities for maintaining a stable construct shape are limited. The current study aimed to address these limitations. Our initial modification involved the addition of exogenous chemokine (C–C motif) ligand 2 (CCL2), which resulted in enhanced adipogenesis and angiogenesis. However, further improvement was required due to delayed blood recanalization. To further optimize the system, a vascularized fibrous capsule derived from an implanted silica expander was utilized as a second modification. We hypothesized this would function as both a microbioreactor to fix the seed cells and exogenous CCL2 locally and as a vascular bed to promote neovascularization. Compared with that of the CCL2 loaded ADSC-HUVECs cell sheet assembled DAT system, adding the silica expander capsule resulted in significantly increased construct stability, new vessel intensity, a greater number of Oil Red O-positive lipid droplets, more enhanced tissue remodeling, and upregulated peroxisome proliferator-activated receptor gamma (PPARγ) & leptin expression. Thus, these two modifications helped optimize the currently available ADSC-HUVEC cell sheet assembled DAT system, providing an adipose tissue construction strategy with enhanced adipogenesis and angiogenesis to reconstruct soft tissue defects. Moreover, close-to-normal leptin expression provided the engineered adipose tissue with a glucometabolic function, in addition to remodeling capabilities. Statement of significanceDelayed neovascularization and unstable adipose formation are the two major problems in tissue engineering adipose. Here, we introduced an adipose tissue engineering construction strategy using a silica expander capsule along with hADSCs-HUVECs cell sheet-assembled DAT in a CCL2-rich microenvironment. Our data suggested that CCL2 could improve angiogenesis and adipogenesis in vitro and in vivo. The addition of tissue expander capsule could further improve the stability of construction and fabricated adipose tissue with increased new vessel intensity, greater numbers of Oil Red O-positive lipid droplets, more enhanced tissue remodeling, and upregulated leptin expression. CCL2 and expander capsule can have clinical utility for soft tissue defects repair, and these two factors can be useful in other tissue engineering.

VEGF loaded porcine decellularized adipose tissue derived hydrogel could enhance angiogenesis in vitro and in vivo

Decellularized adipose tissue (DAT) has been widely applied in soft tissue regeneration, however, DAT may play a promising role in accelerating wound healing because of suitable physical characteristics and biological properties. In this research, we fabricated the DAT hydrogel and the VEGF loaded heparinized-DAT hydrogel (VEGF hydrogel) and evaluated their efficiency in full-thickness skin wound model. We designed one method to encapsulate VEGF to hep-DAT hydrogel in order to control VEGF release rate. Result showed that the VEGF release could last up to 3 day, and 1 ml hep-DAT hydrogel (5 mg/ml) could bind up to (64.521 ± 11.550) ng VEGF which was 4.2 times to that of DAT hydrogels. Moreover, the VEGF released in 3 days still preserved biological activities that the released VEGF could enhance tube formation of HUVECs in vitro. Otherwise, the VEGF hydrogel could significantly accelerate wound healing compared with DAT hydrogel and VEGF injection, collagen deposition and newly formed vessels in the VEGF hydrogel groups were also higher than those of other groups. We believed that the VEGF hydrogel could be one attractive biomaterial for potential clinical applications.

Development and characterization of matrix-derived microcarriers from decellularized tissues using electrospraying techniques.

Stirred bioreactor systems integrating microcarriers represent a promising approach for therapeutic cell manufacturing. While a variety of microcarriers are commercially available, current options do not integrate the tissue-specific composition of the extracellular matrix (ECM), which can play critical roles in directing cell function. The current study sought to generate microcarriers comprised exclusively of ECM from multiple tissue sources. More specifically, porcine decellularized dermis, porcine decellularized myocardium, and human decellularized adipose tissue were digested with α-amylase to obtain ECM suspensions that could be electrosprayed into liquid nitrogen to generate 3D microcarriers that were stable over a range of ECM concentrations without the need for chemical crosslinking or other additives. Characterization studies confirmed that all three microcarrier types had similar soft and compliant mechanical properties and were of a similar size range, but that their composition varied depending on the native tissue source. In vivo testing in immunocompetent mice revealed that the microcarriers integrated into the host tissues, supporting the infiltration of host cells including macrophages and endothelial cells at 2 weeks post-implantation. In vitro cell culture studies validated that the novel microcarriers supported the attachment of tissue-specific stromal cell populations under dynamic culture conditions within spinner flasks, with a significant increase in live cell numbers observed over 1week on the dermal- and adipose-derived microcarriers. Overall, the findings demonstrate the versatility of the electrospraying methods and support the further development of the microcarriers as cell culture and delivery platforms.