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1.
Tissue-engineered blood vessels (TEBVs) are promising in the replacement of diseased vascular tissues. However, it remains a great challenge to obtain a sufficient number of functional smooth muscle cells (SMCs) in a clinical setting to construct patient-specific TEBVs. In addition, it is critical to develop a scaffold to accommodate these cells and retain their functional phenotype for the regeneration of TEBVs. In this study, human induced pluripotent stem cells (iPSCs) were established from primary human aortic fibroblasts, and characterized with the pluripotency markers expression and cells' capabilities to differentiate into all three germ layer cells. A highly efficient method was then developed to induce these human iPSCs into proliferative SMCs. After multiple times of expansion, the expanded SMCs retained the potential to be induced into the functional contractile phenotype of mature SMCs, which was characterized by the contractile response to carbachol treatment, up-regulation of specific collagen genes under transforming growth factor β1 treatment, and up-regulation of specific matrix metalloproteinase genes under cytokine stimulation. We also developed an advanced macroporous and nanofibrous (NF) poly(l-lactic acid) (PLLA) scaffold with suitable pore size and interpore connectivity to seed these human iPSC-derived SMCs and maintain their differentiated phenotype. Subcutaneous implantation of the SMC-scaffold construct in nude mice demonstrated vascular tissue formation, with robust collagenous matrix deposition inside the scaffold and the maintenance of differentiated SMC phenotype. Taken together, this study established an exciting approach towards the construction of patient-specific TEBVs. We established patient-specific human iPSCs, derived proliferative SMCs for expansion, turned on their mature contractile SMC phenotype, and developed an advanced scaffold for these cells to regenerate vascular tissue in vivo.  相似文献   

2.
The inability to adequately vascularize tissues in vitro or in vivo is a major challenge in lung tissue engineering. A method that integrates stem cell research with 3D-scaffold engineering may provide a solution. We have successfully isolated mouse pulmonary stem/progenitor cells (mPSCs) by a two-step procedure and fabricated mPSC-compatible gelatin/microbubble-scaffolds using a 2-channel fluid jacket microfluidic device. We then integrated the cells and the scaffold to construct alveoli-like structures. The mPSCs expressed pro-angiogenic factors (e.g., b-FGF and VEGF) and induced angiogenesis in vitro in an endothelial cell tube formation assay. In addition, the mPSCs were able to proliferate along the inside of the scaffolds and differentiate into type-II and type-I pneumocytes The mPSC-seeded microbubble-scaffolds showed the potential for blood vessel formation in both a chick chorioallantoic membrane (CAM) assay and in experiments for subcutaneous implantation in severe combined immunodeficient (SCID) mice. Our results demonstrate that lung stem/progenitor cells together with gelatin microbubble-scaffolds promote angiogenesis as well as the differentiation of alveolar pneumocytes, resulting in an alveoli-like structure. These findings may help advance lung tissue engineering.  相似文献   

3.
An ideal vascular graft should have the ability to guide the regeneration of neovessels with structure and function similar to those of the native blood vessels. Regeneration of vascular smooth muscle cells (VSMCs) with circumferential orientation within the grafts is crucial for functional vascular reconstruction in vivo. To date, designing and fabricating a vascular graft with well-defined geometric cues to facilitate simultaneously VSMCs infiltration and their circumferential alignment remains a great challenge and scarcely reported in vivo. Thus, we have designed a bi-layered vascular graft, of which the internal layer is composed of circumferentially aligned microfibers prepared by wet-spinning and an external layer composed of random nanofibers prepared by electrospinning. While the internal circumferentially aligned microfibers provide topographic guidance for in vivo regeneration of circumferentially aligned VSMCs, the external random nanofibers can offer enhanced mechanical property and prevent bleeding during and after graft implantation. VSMCs infiltration and alignment within the scaffold was then evaluated in vitro and in vivo. Our results demonstrated that the circumferentially oriented VSMCs and longitudinally aligned ECs were successfully regenerated in vivo after the bi-layered vascular grafts were implanted in rat abdominal aorta. No formation of thrombosis or intimal hyperplasia was observed up to 3 month post implantation. Further, the regenerated neoartery exhibited contraction and relaxation property in response to vasoactive agents. This new strategy may bring cell-free small diameter vascular grafts closer to clinical application.  相似文献   

4.
Host cell recruitment is crucial for vascular graft remodeling and integration into the native blood vessel; it is especially important for cell-free strategies which rely on host remodeling. Controlled release of growth factors from vascular grafts may enhance host cell recruitment. Stromal cell-derived factor (SDF)-1α has been shown to induce host progenitor cell migration and recruitment; however, its potential in regenerative therapies is often limited due to its short half-life in vivo. This report describes a coacervate drug delivery system for enhancing progenitor cell recruitment into an elastomeric vascular graft by conferring protection of SDF-1α. Heparin and a synthetic polycation are used to form a coacervate, which is incorporated into poly(glycerol sebacate) (PGS) scaffolds. In addition to protecting SDF-1α, the coacervate facilitates uniform scaffold coating. Coacervate-laden scaffolds have high SDF-1α loading efficiency and provide sustained release under static and physiologically-relevant flow conditions with minimal initial burst release. In vitro assays showed that coacervate-laden scaffolds enhance migration and infiltration of human endothelial and mesenchymal progenitor cells by maintaining a stable SDF-1α gradient. These results suggest that SDF-1α coacervate-laden scaffolds show great promise for in situ vascular regeneration.  相似文献   

5.
Insufficient neovascularization is associated with high levels of resorption and necrosis in autologous and engineered fat grafts. We tested the hypothesis that incorporating angiogenic growth factor into a scaffold–stem cell construct and implanting this construct around a vascular pedicle improves neovascularization and adipogenesis for engineering soft tissue flaps. Poly(lactic-co-glycolic-acid/polyethylene glycol (PLGA/PEG) microspheres containing vascular endothelial growth factor (VEGF) were impregnated into collagen-chitosan scaffolds seeded with human adipose-derived stem cells (hASCs). This setup was analyzed in vitro and then implanted into isolated chambers around a discrete vascular pedicle in nude rats. Engineered tissue samples within the chambers were harvested and analyzed for differences in vascularization and adipose tissue growth. In vitro testing showed that the collagen-chitosan scaffold provided a supportive environment for hASC integration and proliferation. PLGA/PEG microspheres with slow-release VEGF had no negative effect on cell survival in collagen-chitosan scaffolds. In vivo, the system resulted in a statistically significant increase in neovascularization that in turn led to a significant increase in adipose tissue persistence after 8 weeks versus control constructs. These data indicate that our model—hASCs integrated with a collagen-chitosan scaffold incorporated with VEGF-containing PLGA/PEG microspheres supported by a predominant vascular vessel inside a chamber—provides a promising, clinically translatable platform for engineering vascularized soft tissue flap. The engineered adipose tissue with a vascular pedicle could conceivably be transferred as a vascularized soft tissue pedicle flap or free flap to a recipient site for the repair of soft-tissue defects.  相似文献   

6.
Bioactive, functional scaffolds are required to improve the regenerative potential of stem cells for tissue reconstruction and functional recovery of damaged tissues. Here, we report a paper-based bioactive scaffold platform for stem cell culture and transplantation for bone reconstruction. The paper scaffolds are surface-engineered by an initiated chemical vapor deposition process for serial coating of a water-repellent and cell-adhesive polymer film, which ensures the long-term stability in cell culture medium and induces efficient cell attachment. The prepared paper scaffolds are compatible with general stem cell culture and manipulation techniques. An optimal paper type is found to provide structural, physical, and mechanical cues to enhance the osteogenic differentiation of human adipose-derived stem cells (hADSCs). A bioactive paper scaffold significantly enhances in vivo bone regeneration of hADSCs in a critical-sized calvarial bone defect. Stacking the paper scaffolds with osteogenically differentiated hADSCs and human endothelial cells resulted in vascularized bone formation in vivo. Our study suggests that paper possesses great potential as a bioactive, functional, and cost-effective scaffold platform for stem cell-mediated bone tissue engineering. To the best of our knowledge, this is the first study reporting the feasibility of a paper material for stem cell application to repair tissue defects.  相似文献   

7.
Cartilage regeneration after trauma is still a great challenge for clinicians and researchers due to many reasons, such as joint load-bearing, synovial movement and the paucity of endogenous repair cells. To overcome these limitations, we constructed a functional biomaterial using a biphasic scaffold platform and a bone-derived mesenchymal stem cells (BMSCs)-specific affinity peptide. The biphasic scaffold platform retains more cells homogeneously within the sol–gel transition of chitosan and provides sufficient solid matrix strength. This biphasic scaffold platform is functionalized with an affinity peptide targeting a cell source of interest, BMSCs. The presence of conjugated peptide gives this system a biological functionality towards BMSC-specific homing both in vitro and in vivo. The functional biomaterial can stimulate stem cell proliferation and chondrogenic differentiation during in vitro culture. Six months after in vivo implantation, compared with routine surgery or control scaffolds, the functional biomaterials induced superior cartilage repair without complications, as indicated by histological observations, magnetic resonance imaging and biomechanical properties. Beyond cartilage repair, this functional biphasic scaffold may provide a biomaterial framework for one-step tissue engineering strategy by homing endogenous cells to stimulate tissue regeneration.  相似文献   

8.
Donor shortage remains a continued challenge in liver transplantation. Recent advances in tissue engineering have provided the possibility of creating functional liver tissues as an alternative to donor organ transplantation. Small bioengineered liver constructs have been developed, however a major challenge in achieving functional bioengineered liver in vivo is the establishment of a functional vasculature within the scaffolds. Our overall goal is to bioengineer intact livers, suitable for transplantation, using acellular porcine liver scaffolds. We developed an effective method for reestablishing the vascular network within decellularized liver scaffolds by conjugating anti-endothelial cell antibodies to maximize coverage of the vessel walls with endothelial cells. This procedure resulted in uniform endothelial attachment throughout the liver vasculature extending to the capillary bed of the liver scaffold and greatly reduced platelet adhesion upon blood perfusion in vitro. The re-endothelialized livers, when transplanted to recipient pigs, were able to withstand physiological blood flow and maintained for up to 24 h. This study demonstrates, for the first time, that vascularized bioengineered livers, of clinically relevant size, can be transplanted and maintained in vivo, and represents the first step towards generating engineered livers for transplantation to patients with end-stage liver failure.  相似文献   

9.
The goal of regenerative medicine is to achieve histological and functional recovery to the level of the original tissue. For this purpose, we have developed a biodegradable scaffold to create cell-free in-situ tissue-engineered vasculature (iTEV) with good long-term results. However, the regeneration process of vascular smooth muscle cells (VSMCs) over time has yet to be examined. To evaluate the regeneration ability of VSMCs, the inferior vena cava of experimental animals was replaced with iTEV, and tested at 1, 3, 6, 12, and 24 months (n = 6 each) after implantation. Six animals were enrolled to compare 24-month iTEV and native vasculature in single individual samples. There were no complications throughout the study. Immunohistology, protein expression analysis, and biochemical findings indicate that iTEV can gradually regenerate and develop into a mature vessel within 24 months using our biodegradable scaffold. These results provide a time course for the regeneration of VSMCs within the tissue-engineered vascular autograft constructed using a biodegradable scaffold.  相似文献   

10.
Cardiac tissue engineering is a promising technique to regenerate cardiac tissue and treat cardiovascular disease. Here we applied a modified method to generate ultrafine uniformly-aligned composite gelatin/polycaprolactone fibers that mimic functional heart tissue. We tested the physical properties of these fibers and analyzed how these composite fibrous scaffolds affected growth and cardiac lineage differentiation in rat adipose-derived stem cells (rADSCs). We found that uniformly aligned composite fiber scaffolds had an anisotropic arrangement, functional mechanical properties, and strong hydrophilicity. The anisotropic scaffolds improved cell attachment, viability, and proliferative capacity of ADSCs over randomly-aligned scaffolds. Furthermore, uniformly aligned composite fiber scaffolds increased the efficiency of cardiomyogenic differentiation, but might reduce the efficiency of cardiac conduction system cell differentiation in ADSCs compared to randomly-oriented scaffolds and tissue culture polystyrene. However, the randomly-oriented composite scaffolds showed no obviously facilitated effects over tissue culture polystyrene on the two cells’ differentiation process. The above results indicate that the scaffold fiber alignment has a greater effect on cell differentiation than the composition of the scaffold. Together, the uniformly-aligned composite fibers displayed excellent physical and biocompatible properties, promoted ADSC proliferation, and played distinct roles in the differentiation of cardiomyogenic cells and cardiac conduction system cells from ADSCs. These results provide new insight for the application of anisotropic fibrous scaffolds in cardiac tissue engineering for both in vitro and in vivo research.  相似文献   

11.
Osteoarthritis is the most common joint disorder affecting millions of people. Most scaffolds developed for cartilage regeneration fail due to vascularization and matrix mineralization. In this study we present a chondrogenic extracellular matrix (ECM) incorporated collagen/chitosan scaffold (chondrogenic ECM scaffold) for potential use in cartilage regenerative therapy. Biochemical characterization showed that these scaffolds possess key pro-chondrogenic ECM components and growth factors. MRI characterization showed that the scaffolds possess mechanical properties and diffusion characteristics important for cartilage tissue regeneration. In vivo implantation of the chondrogenic ECM scaffolds with bone marrow derived mesenchymal stem cells (MSCs) triggered chondrogenic differentiation of the MSCs without the need for external stimulus. Finally, results from in vivo MRI experiments indicate that the chondrogenic ECM scaffolds are stable and possess MR properties on par with native cartilage. Based on our results, we envision that such ECM incorporated scaffolds have great potential in cartilage regenerative therapy. Additionally, our validation of MR parameters with histology and biochemical analysis indicates the ability of MRI techniques to track the progress of our ECM scaffolds non-invasively in vivo; highlighting the translatory potential of this technology.  相似文献   

12.
Liver tissue engineering requires a suitable cell source, methodologies to assemble the cells within their niche microenvironments in a spatially defined manner, and vascularization of the construct in vivo for maintenance of hepatocyte viability and function. Recently, we have developed methods of encapsulating cells within separate domains in multi-component hydrogel fibers and methods of assembling fibers to form 3D-patterned tissue constructs. In the present work, we have combined these approaches to encapsulate hepatocytes and endothelial cells within their specific niches, and to assemble them into endothelialized liver tissue constructs. The hepatocytes and endothelial cells were obtained in parallel by differentiating human recombinant protein-induced human pluripotent stem cells, resulting in a construct which contained genetically identical endothelial and parenchymal elements. We were able to demonstrate that the presence of endothelial cells in the scaffold significantly improved hepatocyte function in vitro and facilitated vascularization of the scaffold when implanted in a mouse partial hepatectomy model. The in vivo studies further asserted that integration of the scaffold with host vasculature had occurred, as demonstrated by the presence of human albumin in the mouse serum.  相似文献   

13.
While stem cell niches in vivo are complex three-dimensional (3D) microenvironments, the relationship between the dimensionality of the niche to its function is unknown. We have created a 3D microenvironment through electrospinning to study the impact of geometry and different extracellular proteins on the development of cardiac progenitor cells (Flk-1+) from resident stem cells and their differentiation into functional cardiovascular cells. We have investigated the effect of collagen IV, fibronectin, laminin and vitronectin on the adhesion and proliferation of murine ES cells as well as the effects of these proteins on the number of Flk-1+ cells cultured in 2D conditions compared to 3D system in a feeder free condition. We found that the number of Flk-1+ cells was significantly higher in 3D scaffolds coated with laminin or vitronectin compared to colIV-coated scaffolds. Our results show the importance of defined culture systems in vitro for studying the guided differentiation of pluripotent embryonic stem cells in the field of cardiovascular tissue engineering and regenerative medicine.  相似文献   

14.
Cancer therapeutics are developed through extensive screening; however, many therapeutics evaluated with 2D in vitro cultures during pre-clinical trials suffer from lower efficacy in patients. Replicating the in vivo tumor microenvironment in vitro with three-dimensional (3D) porous scaffolds offers the possibility of generating more predictive pre-clinical models to enhance cancer treatment efficacy. We developed a chitosan and hyaluronic acid (HA) polyelectrolyte complex 3D porous scaffold and evaluated its physical properties. Chitosan-HA (C-HA) scaffolds had a highly porous network. C-HA scaffolds were compared to 2D surfaces for in vitro culture of U-118 MG human glioblastoma (GBM) cells. C-HA scaffold cultures promoted tumor spheroid formation and increased stem-like properties of GBM cells as evidenced by the upregulation of CD44, Nestin, Musashi-1, GFAP, and HIF-1α as compared with 2D cultures. Additionally, the invasiveness of GBM cells cultured in C-HA scaffolds was significantly enhanced compared to those grown in 2D cultures. C-HA scaffold cultures were also more resistant to chemotherapy drugs, which corresponded to the increased expression of ABCG2 drug efflux transporter. These findings suggest that C-HA scaffolds offer promise as an in vitro GBM platform for study and screening of novel cancer therapeutics.  相似文献   

15.
Despite the promise for stem cell-based tissue engineering for regenerative therapy, slow and insufficient vascularization of large tissue constructs negatively impacts the survival and function of these transplanted cells. A combination of channeled porous silk scaffolds and prevascularization with endothelial cells was investigated to test the ability of this tissue engineering strategy to support rapid and extensive vascularization process. We report that hollow channels promote in vitro prevascularization by facilitating endothelial cell growth, VEGF secretion, and capillary-like tube formation. When implanted in vivo, the pre-established vascular networks in the hollow channel scaffolds anastomose with host vessels and exhibit accelerated vascular infiltration throughout the whole tissue construct, which provides timely and sufficient nutrients to ensure the survival of the transplanted stem cells. This tissue engineering strategy can promote the effective application of stem cell-based regeneration to improve future clinical applications.  相似文献   

16.
A defined xeno-free system for patient-specific iPSC derivation and differentiation is required for translation to clinical applications. However, standard somatic cell reprogramming protocols rely on using MEFs and xenogeneic medium, imposing a significant obstacle to clinical translation. Here, we describe a well-defined culture system based on xeno-free media and LN521 substrate which supported i) efficient reprogramming of normal or diseased skin fibroblasts from human of different ages into hiPSCs with a 15–30 fold increase in efficiency over conventional viral vector-based method; ii) long-term self-renewal of hiPSCs; and iii) direct hiPSC lineage-specific differentiation. Using an excisable polycistronic vector and optimized culture conditions, we achieved up to 0.15%–0.3% reprogramming efficiencies. Subsequently, transgene-free hiPSCs were obtained by Cre-mediated excision of the reprogramming factors. The derived iPSCs maintained long-term self-renewal, normal karyotype and pluripotency, as demonstrated by the expression of stem cell markers and ability to form derivatives of three germ layers both in vitro and in vivo. Importantly, we demonstrated that Parkinson's patient transgene-free iPSCs derived using the same system could be directed towards differentiation into dopaminergic neurons under xeno-free culture conditions. Our approach provides a safe and robust platform for the generation of patient-specific iPSCs and derivatives for clinical and translational applications.  相似文献   

17.
Acellular scaffolds from complex whole organs such as lung are being increasingly studied for ex vivo organ generation and for in vitro studies of cell–extracellular matrix interactions. We have established effective methods for efficient de and recellularization of large animal and human lungs including techniques which allow multiple small segments (∼1–3 cm3) to be excised that retain 3-dimensional lung structure. Coupled with the use of a synthetic pleural coating, cells can be selectively physiologically inoculated via preserved vascular and airway conduits. Inoculated segments can be further sliced for high throughput studies. Further, we demonstrate thermography as a powerful noninvasive technique for monitoring perfusion decellularization and for evaluating preservation of vascular and airway networks following human and porcine lung decellularization. Collectively, these techniques are a significant step forward as they allow high throughput in vitro studies from a single lung or lobe in a more biologically relevant, three-dimensional acellular scaffold.  相似文献   

18.
Tissue engineering provides a promising alternative therapy to the complex surgical reconstruction of auricular cartilage by using ear-shaped autologous costal cartilage. Bacterial nanocellulose (BNC) is proposed as a promising scaffold material for auricular cartilage reconstruction, as it exhibits excellent biocompatibility and secures tissue integration. Thus, this study evaluates a novel bilayer BNC scaffold for auricular cartilage tissue engineering. Bilayer BNC scaffolds, composed of a dense nanocellulose layer joined with a macroporous composite layer of nanocellulose and alginate, were seeded with human nasoseptal chondrocytes (NC) and cultured in vitro for up to 6 weeks. To scale up for clinical translation, bilayer BNC scaffolds were seeded with a low number of freshly isolated (uncultured) human NCs combined with freshly isolated human mononuclear cells (MNC) from bone marrow in alginate and subcutaneously implanted in nude mice for 8 weeks. 3D morphometric analysis showed that bilayer BNC scaffolds have a porosity of 75% and mean pore size of 50 ± 25 μm. Furthermore, endotoxin analysis and in vitro cytotoxicity testing revealed that the produced bilayer BNC scaffolds were non-pyrogenic (0.15 ± 0.09 EU/ml) and non-cytotoxic (cell viability: 97.8 ± 4.7%). This study demonstrates that bilayer BNC scaffolds offer a good mechanical stability and maintain a structural integrity while providing a porous architecture that supports cell ingrowth. Moreover, bilayer BNC scaffolds provide a suitable environment for culture-expanded NCs as well as a combination of freshly isolated NCs and MNCs to form cartilage in vitro and in vivo as demonstrated by immunohistochemistry, biochemical and biomechanical analyses.  相似文献   

19.
Zhang Y  Yang F  Liu K  Shen H  Zhu Y  Zhang W  Liu W  Wang S  Cao Y  Zhou G 《Biomaterials》2012,33(10):2926-2935
The success of in vitro cartilage regeneration provides a promising approach for cartilage repair. However, the currently engineered cartilage in vitro is unsatisfactory for clinical application due to non-homogeneous structure, inadequate thickness, and poor mechanical property. It has been widely reported that orientation of scaffolds can promote cell migration and thus probably contributes to improving tissue regeneration. This study explored the impact of microtubular oriented scaffold on in vitro cartilage regeneration. Porcine articular chondrocytes were seeded into microtubule-oriented PLGA scaffolds and non-oriented scaffolds respectively. A long-term in vitro culture followed by a long-term in vivo implantation was performed to evaluate the influence of scaffold orientation on cartilage regeneration. The current results showed that the oriented scaffolds could efficiently promote cell migration towards the inner region of the constructs. After 12 weeks of in vitro culture, the chondrocyte-scaffold constructs in the oriented group formed thicker cartilage with more homogeneous structure, stronger mechanical property, and higher cartilage matrix content compared to the non-oriented group. Furthermore, the in vitro engineered cartilage based on oriented scaffolds showed better cartilage formation in terms of size, wet weight, and homogeneity after 12-week in vivo implantation in nude mice. These results indicated that the longitudinal microtubular orientation of scaffolds can efficiently improve the structure and function of in vitro engineered cartilage.  相似文献   

20.
Human dental pulp cells (hDPCs) are a valuable source for the generation of patient-specific human induced pluripotent stem cells (hiPSCs). An advanced strategy for the safe and efficient reprogramming of hDPCs and subsequent lineage-specific differentiation is a critical step toward clinical application. In present research, we successfully generated hDPC-iPSCs using only two non-oncogenic factors: Oct4 and Sox2 (2F hDPC-hiPSCs) and evaluated the feasibility of hDPC-iPSCs as substrates for endothelial progenitor cells (EPCs), contributing to EPC-based therapies. Under conventional differentiation conditions, 2F hDPC-hiPSCs showed higher differentiation efficiency, compared to hiPSCs from other cell types, into multipotent CD34+ EPCs (2F-hEPCs) capable to differentiate into functional endothelial and smooth muscle cells. The angiogenic and neovasculogenic activities of 2F-hEPCs were confirmed using a Matrigel plug assay in mice. In addition, the therapeutic effects of 2F-hEPC transplantation were confirmed in mouse models of hind-limb ischemia and myocardial infarction. Importantly, 2F-EPCs effectively integrated into newly formed vascular structures and enhanced neovascularization via likely both direct and indirect paracrine mechanisms. 2F hDPC-hiPSCs have a robust capability for the generation of angiogenic and vasculogenic EPCs, representing a strategy for patient-specific EPC therapies and disease modeling, particularly for ischemic vascular diseases.  相似文献   

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