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Almalla A, Elomaa L, Bechtella L, Daneshgar A, Yavvari P, Mahfouz Z, Tang P, Koksch B, Sauer I, Pagel K, Hillebrandt KH, Weinhart M. Papain-Based Solubilization of Decellularized Extracellular Matrix for the Preparation of Bioactive, Thermosensitive Pregels. Biomacromolecules 2023; 24:5620-5637. [PMID: 38009757 PMCID: PMC10716854 DOI: 10.1021/acs.biomac.3c00602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/17/2023] [Accepted: 10/25/2023] [Indexed: 11/29/2023]
Abstract
Solubilized, gel-forming decellularized extracellular matrix (dECM) is used in a wide range of basic and translational research and due to its inherent bioactivity can promote structural and functional tissue remodeling. The animal-derived protease pepsin has become the standard proteolytic enzyme for the solubilization of almost all types of collagen-based dECM. In this study, pepsin was compared with papain, α-amylase, and collagenase for their potential to solubilize porcine liver dECM. Maximum preservation of bioactive components and native dECM properties was used as a decisive criterion for further application of the enzymes, with emphasis on minimal destruction of the protein structure and maintained capacity for physical thermogelation at neutral pH. The solubilized dECM digests, and/or their physically gelled hydrogels were characterized for their rheological properties, gelation kinetics, GAG content, proteomic composition, and growth factor profile. This study highlights papain as a plant-derived enzyme that can serve as a cost-effective alternative to animal-derived pepsin for the efficient solubilization of dECM. The resulting homogeneous papain-digested dECM preserved its thermally triggered gelation properties similar to pepsin digests, and the corresponding dECM hydrogels demonstrated their enhanced bioadhesiveness in single-cell force spectroscopy experiments with fibroblasts. The viability and proliferation of human HepaRG cells on dECM gels were similar to those on pure rat tail collagen type I gels. Papain is not only highly effective and economically attractive for dECM solubilization but also particularly interesting when digesting human-tissue-derived dECM for regenerative applications, where animal-derived materials are to be avoided.
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Affiliation(s)
- Ahed Almalla
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Laura Elomaa
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Leïla Bechtella
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Assal Daneshgar
- Experimental
Surgery, Department of Surgery, CCM|CVK, Charité − Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Prabhu Yavvari
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Zeinab Mahfouz
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Peter Tang
- Experimental
Surgery, Department of Surgery, CCM|CVK, Charité − Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Beate Koksch
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Igor Sauer
- Experimental
Surgery, Department of Surgery, CCM|CVK, Charité − Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Kevin Pagel
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
- Fritz
Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
| | - Karl Herbert Hillebrandt
- Experimental
Surgery, Department of Surgery, CCM|CVK, Charité − Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
- Berlin
Institute of Health at Charité − Universitätsmedizin
Berlin, BIH Biomedical Innovation Academy, BIH Charité, Clinician
Scientist Program, Charitéplatz
1, 10117 Berlin, Germany
| | - Marie Weinhart
- Institute
of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
- Institute
of Physical Chemistry and Electrochemistry, Leibniz Universität
Hannover, 30167 Hannover, Germany
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Nellinger S, Kluger PJ. How Mechanical and Physicochemical Material Characteristics Influence Adipose-Derived Stem Cell Fate. Int J Mol Sci 2023; 24:ijms24043551. [PMID: 36834966 PMCID: PMC9961531 DOI: 10.3390/ijms24043551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/28/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
Adipose-derived stem cells (ASCs) are a subpopulation of mesenchymal stem cells. Compared to bone marrow-derived stem cells, they can be harvested with minimal invasiveness. ASCs can be easily expanded and were shown to be able to differentiate into several clinically relevant cell types. Therefore, this cell type represents a promising component in various tissue engineering and medical approaches (e.g., cell therapy). In vivo cells are surrounded by the extracellular matrix (ECM) that provides a wide range of tissue-specific physical and chemical cues, such as stiffness, topography, and chemical composition. Cells can sense the characteristics of their ECM and respond to them in a specific cellular behavior (e.g., proliferation or differentiation). Thus, in vitro biomaterial properties represent an important tool to control ASCs behavior. In this review, we give an overview of the current research in the mechanosensing of ASCs and current studies investigating the impact of material stiffens, topography, and chemical modification on ASC behavior. Additionally, we outline the use of natural ECM as a biomaterial and its interaction with ASCs regarding cellular behavior.
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Affiliation(s)
- Svenja Nellinger
- Reutlingen Research Institute, Reutlingen University, 72762 Reutlingen, Germany
| | - Petra Juliane Kluger
- School of Life Sciences, Reutlingen University, 72762 Reutlingen, Germany
- Correspondence: ; Tel.: +49-07121-271-2061
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Herrera Quijano MA, Sharma N, Morissette Martin P, Séguin CA, Flynn LE. Development of 2-D and 3-D culture platforms derived from decellularized nucleus pulposus. Front Bioeng Biotechnol 2022; 10:937239. [PMID: 36237211 PMCID: PMC9551564 DOI: 10.3389/fbioe.2022.937239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
Bioscaffolds derived from the extracellular matrix (ECM) have shown the capacity to promote regeneration by providing tissue-specific biological instructive cues that can enhance cell survival and direct lineage-specific differentiation. This study focused on the development and characterization of two-dimensional (2-D) and three-dimensional (3-D) cell culture platforms incorporating decellularized nucleus pulposus (DNP). First, a detergent-free protocol was developed for decellularizing bovine nucleus pulposus (NP) tissues that was effective at removing cellular content while preserving key ECM constituents including collagens, glycosaminoglycans, and the cell-adhesive glycoproteins laminin and fibronectin. Next, novel 2-D coatings were generated using the DNP or commercially-sourced bovine collagen type I (COL) as a non-tissue-specific control. In addition, cryo-milled DNP or COL particles were incorporated within methacrylated chondroitin sulphate (MCS) hydrogels as a 3-D cell culture platform for exploring the effects of ECM particle composition. Culture studies showed that the 2-D coatings derived from the DNP could support cell attachment and growth, but did not maintain or rescue the phenotype of primary bovine NP cells, which de-differentiated when serially passaged in monolayer culture. Similarly, while bovine NP cells remained highly viable following encapsulation and 14 days of culture within the hydrogel composites, the incorporation of DNP particles within the MCS hydrogels was insufficient to maintain or rescue changes in NP phenotype associated with extended in vitro culture based on gene expression patterns. Overall, DNP produced with our new decellularization protocol was successfully applied to generate both 2-D and 3-D bioscaffolds; however, further studies are required to assess if these platforms can be combined with additional components of the endogenous NP microenvironment to stimulate regeneration or lineage-specific cell differentiation.
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Affiliation(s)
- Marco A. Herrera Quijano
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
- Bone and Joint Institute, The University of Western Ontario, London, ON, Canada
| | - Nadia Sharma
- Bone and Joint Institute, The University of Western Ontario, London, ON, Canada
- School of Biomedical Engineering, The University of Western Ontario, London, ON, Canada
| | - Pascal Morissette Martin
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Cheryle A. Séguin
- Bone and Joint Institute, The University of Western Ontario, London, ON, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
- *Correspondence: Lauren E. Flynn, ; Cheryle A. Séguin,
| | - Lauren E. Flynn
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
- Bone and Joint Institute, The University of Western Ontario, London, ON, Canada
- School of Biomedical Engineering, The University of Western Ontario, London, ON, Canada
- Department of Chemical and Biochemical Engineering, Faculty of Engineering, The University of Western Ontario, London, ON, Canada
- *Correspondence: Lauren E. Flynn, ; Cheryle A. Séguin,
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Tutak FN, Kıvrak EG. The Effect of Human Umbilical Cord-Derived Lyophilized Stem Cells on Fat Graft Viability: An Experimental Study. Aesthetic Plast Surg 2022; 46:1973-1982. [PMID: 35303121 DOI: 10.1007/s00266-022-02836-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 02/24/2022] [Indexed: 12/30/2022]
Abstract
OBJECTIVE The extended use of autologous adipose tissue has increased the importance of the viability of fat graft cells. This experimental animal study assesses the effects of lyophilized mesenchymal stem cells on the viability and survival of autologous fat grafts. METHODS For this prospective treatment control study, 27 male Wistar albino rats were divided into three groups, each containing nine animals. In Group 1 (control), an incision was made in the right inguinal region, and the skin was closed with 4/0 prolene sutures. In Groups 2 and 3, fat pads collected from the right groin of the rats were lipoaspirated and placed on the sternum as a subcutaneous fat graft. The skin was then closed with 4/0 prolene sutures. Saline was added to the fat grafts of the Group 2 (sham) rats, and placenta-derived mesenchymal stem cell lyophilizate (MSC-L) was administered to the fat graft in the Group 3 (treatment) rats. After three months of treatment, the adipose tissue harvested from Group 1 and the fat grafts taken from Groups 2 and 3 were assessed histopathologically, stereologically and biochemically. RESULTS Adipose tissue volume was lower in Group 2 than in Groups 1 and 3, and the adipose tissue treated with MSC-L in Group 3 was better preserved than that in Group 1. Connective tissue and vascular volumes were greater in Group 3 than those in the other groups. The normal structures of adipocytes, fibrous tissues and vessels were better preserved in Group 3 than in Group 2, and a large number of new blood vessels were noted to have formed in Group 3. Damaged cystic cells, areas of calcification and degenerated adipocytes were noted in Group 2, while the G3PDH levels increased significantly more in Group 3 than in Group 2. CONCLUSION It was shown that MSC-L treatment plays an active role in maintaining the volume and survival of fat grafts by promoting neovascularization in this animal experimental study. NO LEVEL ASSIGNED This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.
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Affiliation(s)
- Fatma Nilay Tutak
- Division of Plastic, Reconstructive and Aesthetic Surgery, Medical Faculty, Adiyaman University, Adiyaman, Turkey.
| | - Elfide Gizem Kıvrak
- Division of Histology and Embryology, Medical Faculty, Adiyaman University, Adiyaman, Turkey
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Zhang G, Ci H, Ma C, Li Z, Jiang W, Chen L, Wang Z, Zhou M, Sun J. Additive manufactured macroporous chambers facilitate large volume soft tissue regeneration from adipose-derived extracellular matrix. Acta Biomater 2022; 148:90-105. [PMID: 35671873 DOI: 10.1016/j.actbio.2022.05.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/12/2022] [Accepted: 05/31/2022] [Indexed: 12/12/2022]
Abstract
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 SIGNIFICANCE: Decellularized 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.
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Affiliation(s)
- Guo Zhang
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China
| | - Hai Ci
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China; Department of Burn and Plastic Surgery, the First Affiliated Hospital of Medical College of Shihezi University, Shihezi, Xinjiang 832008, China
| | - Chenggong Ma
- Department of Pathology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zhipeng Li
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China
| | - Wenbin Jiang
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China
| | - Lifeng Chen
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China
| | - Zhenxing Wang
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China
| | - Muran Zhou
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China.
| | - Jiaming Sun
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Wuhan Clinical Research Center for Superficial Organ Reconstruction, Wuhan 430022, China.
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Shengnan Q, Bennett S, Wen W, Aiguo L, Jiake X. The role of tendon derived stem/progenitor cells and extracellular matrix components in the bone tendon junction repair. Bone 2021; 153:116172. [PMID: 34506992 DOI: 10.1016/j.bone.2021.116172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/22/2021] [Accepted: 09/02/2021] [Indexed: 12/29/2022]
Abstract
Fibrocartilage enthesis is the junction between bone and tendon with a typical characteristics of fibrocartilage transition zones. The regeneration of this transition zone is the bottleneck for functional restoration of bone tendon junction (BTJ). Biomimetic approaches, especially decellularized extracellular matrix (ECM) materials, are strategies which aim to mimic the components of tissues to the utmost extent, and are becoming popular in BTJ healing because of their ability not only to provide scaffolds to allow cells to attach and migrate, but also to provide a microenvironment to guide stem/progenitor cells lineage-specific differentiation. However, the cellular and molecular mechanisms of those approaches, especially the ECM proteins, remain unclear. For BTJ reconstruction, fibrocartilage regeneration is the key for good integrity of bone and tendon as well as its mechanical recovery, so the components which can guide stem cells to a chondrogenic commitment in biomimetic approaches might well be the key for fibrocartilage regeneration and eventually for the better BTJ healing. In this review, we firstly discuss the importance of cartilage-like formation in the healing process of BTJ. Next, we explore the possibility of tendon-derived stem/progenitor cells as cell sources for BTJ regeneration due to their multi-differentiation potential. Finally, we summarize the role of extracellular matrix components of BTJ in guiding stem cell fate to a chondrogenic commitment, so as to provide cues for understanding the mechanisms of lineage-specific potential of biomimetic approaches as well as to inspire researchers to incorporate unique ECM components that facilitate BTJ repair into design.
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Affiliation(s)
- Qin Shengnan
- Guangzhou Institute of Traumatic Surgery, Department of Orthopedics, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, China
| | - Samuel Bennett
- School of Biomedical Sciences, The University of Western Australia, Perth, Australia
| | - Wang Wen
- Guangzhou Institute of Traumatic Surgery, Department of Orthopedics, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, China
| | - Li Aiguo
- Guangzhou Institute of Traumatic Surgery, Department of Orthopedics, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, China.
| | - Xu Jiake
- School of Biomedical Sciences, The University of Western Australia, Perth, Australia.
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Li S, Liu Y, McCann J, Ravnic DJ, Gimble JM, Hayes DJ. Hybrid adipose graft materials synthesized from chemically modified adipose extracellular matrix. J Biomed Mater Res A 2021; 110:156-163. [PMID: 34263999 DOI: 10.1002/jbm.a.37273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/24/2021] [Accepted: 07/07/2021] [Indexed: 12/17/2022]
Abstract
Decellularized extracellular matrix (ECM) from tissues is a promising biomaterial that can provide a complex 3D microenvironment capable of modulating cell response and tissue regeneration. In this study, we have integrated the decellularized thiolated adipose-derived ECM, at different concentrations, with polyethylene glycol (PEG) using Michael addition between thiol and acrylate moieties. The potential for this material to support adipogenic differentiation of human adipose-derived stem cells was evaluated by encapsulating cells in hydrogels with increasing concentrations of chemically modified ECM (mECM). Our results demonstrated a positive correlation between the ECM content in the hydrogels and cell proliferation, adipogenic marker expression, and lipid formation and accumulation. Furthermore, we have shown host cell infiltration and enhanced adipogenesis in vivo after implantation. These findings support the graft as a potential alternative for adipose tissue regeneration.
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Affiliation(s)
- Shue Li
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Yiming Liu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Jacob McCann
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Dino J Ravnic
- Department of Surgery, Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Jeffrey M Gimble
- Obatala Sciences, Inc., Advanced Materials Research Institute, University of New Orleans, New Orleans, Louisiana, USA
| | - Daniel J Hayes
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA.,Material Research Institute, The Pennsylvania State University, University Park, Pennsylvania, USA.,The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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Modular cell-assembled adipose matrix-derived bead foams as a mesenchymal stromal cell delivery platform for soft tissue regeneration. Biomaterials 2021; 275:120978. [PMID: 34182328 DOI: 10.1016/j.biomaterials.2021.120978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 12/19/2022]
Abstract
With the goal of establishing a new clinically-relevant bioscaffold format to enable the delivery of high densities of human adipose-derived stromal cells (ASCs) for applications in soft tissue regeneration, a novel "cell-assembly" method was developed to generate robust 3-D scaffolds comprised of fused networks of decellularized adipose tissue (DAT)-derived beads. In vitro studies confirmed that the assembly process was mediated by remodelling of the extracellular matrix by the seeded ASCs, which were well distributed throughout the scaffolds and remained highly viable after 8 days in culture. The ASC density, sulphated glycosaminoglycan content and scaffold stability were enhanced under culture conditions that included growth factor preconditioning. In vivo testing was performed to compare ASCs delivered within the cell-assembled DAT bead foams to an equivalent number of ASCs delivered on a previously-established pre-assembled DAT bead foam platform in a subcutaneous implant model in athymic nude mice. Scaffolds were fabricated with human ASCs engineered to stably co-express firefly luciferase and tdTomato to enable long-term cell tracking. Longitudinal bioluminescence imaging showed a significantly stronger signal associated with viable human ASCs at timepoints up to 7 days in the cell-assembled scaffolds, although both implant groups were found to retain similar densities of human ASCs at 28 days. Notably, the infiltration of CD31+ murine endothelial cells was enhanced in the cell-assembled implants at 28 days. Moreover, microcomputed tomography angiography revealed that there was a marked reduction in vascular permeability in the cell-assembled group, indicating that the developing vascular network was more stable in the new scaffold format. Overall, the novel cell-assembled DAT bead foams represent a promising platform to harness the pro-regenerative paracrine functionality of human ASCs and warrant further investigation as a clinically-translational approach for volume augmentation.
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