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Mesenchymal stromal cells (MSCs) are increasingly combined with biomaterials to enhance their therapeutic properties, including their immunosuppressive function. However, clinical trials utilizing MSCs with or without biomaterials have shown limited success, potentially due to their functional heterogeneity across different donors and among different subpopulations of cells. Here, we evaluated the immunosuppressive capacity, as measured by the ability to reduce T-cell proliferation and activation, of interferon-gamma (IFN-γ)-licensed MSCs from multiple donors on fibrin and collagen hydrogels, the two most commonly utilized biomaterials in combination with MSCs in clinical trials worldwide according to ClinicalTrials.gov Variations in the immunosuppressive capacity between IFN-γ-licensed MSC donors on the biomaterials correlated with the magnitude of indoleamine-2,3-dioxygenase activity. Immunosuppressive capacity of the IFN-γ-licensed MSCs depended on the αV/α5 integrins when cultured on fibrin and on the α2/ß1 integrins when cultured on collagen. While all tested MSCs were nearly 100% positive for these integrins, sorted MSCs that expressed higher levels of αV/α5 integrins demonstrated greater immunosuppressive capacity with IFN-γ licensing than MSCs that expressed lower levels of these integrins on fibrin. These findings were equivalent for MSCs sorted based on the α2/ß1 integrins on collagen. These results demonstrate the importance of integrin engagement to IFN-γ licensed MSC immunosuppressive capacity and that IFN-γ-licensed MSC subpopulations of varying immunosuppressive capacity can be identified by the magnitude of integrin expression specific to each biomaterial.
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Colágeno/metabolismo , Fibrina/metabolismo , Terapia de Imunossupressão , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Integrina alfa2beta1/metabolismo , Interferon gama/farmacologia , Células-Tronco Mesenquimais/citologia , Antivirais/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Colágeno/química , Fibrina/química , Humanos , Hidrogéis/química , Hidrogéis/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismoRESUMO
Given the increased recognition of the importance of physiologically relevant microenvironments when designing in vitro assays, microphysiological systems (MPS) that mimic the critical function and structure of tissues and organs have gained considerable attention as alternatives to traditional experimental models. Accordingly, the field is growing rapidly, and some promising MPS are being tested for use in pharmaceutical development and toxicological testing. However, most MPS are complex and require additional infrastructure, which limits their successful translation. Here, we present a pumpless, modular MPS consisting of 1) a resistance module that controls flow rate and 2) a physiologically relevant, three-dimensional blood vessel module. Flow is provided by an attached reservoir tank that feeds fluid into the resistance channel via hydrostatic pressure. The flow rate is controlled by the height of the media in the tank and the resistance channel's dimensions. The flow from the resistance module is streamed into the blood vessel module using a liquid bridge. We utilize optical coherence tomography (OCT) to measure fluid velocity at regions of interest. The endothelial cells cultured in the MPS remain viable for up to 14 days and demonstrate the functional characteristics of the human blood vessels verified by tight junction expression and diffusion assay. Our results show that a modular MPS can simulate a functional endothelium in vitro while simplifying the operation of the MPS. The simplicity of the system allows for modifications to incorporate other microenvironmental components and to build other organ-modeling systems easily.
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Células Endoteliais , Dispositivos Lab-On-A-Chip , Humanos , PerfusãoRESUMO
This study investigated the chondrogenic activity of encapsulated mesenchymal stem cells (MSCs) and articular chondrocytes (ACs) and its impact on the mechanical properties of injectable poly(N-isopropylacrylamide)-based dual-network hydrogels loaded with poly( l -lysine) (PLL). To this effect, an ex vivo study model was employed to assess the behavior of the injected hydrogels-specifically, their surface stiffness and integration strength with the surrounding cartilage. The highest chondrogenic activity was observed from AC-encapsulated hydrogels, while the effect of PLL on MSC chondrogenesis was not apparent from biochemical analyses. Mechanical testing showed that there were no significant differences in either surface stiffness or integration strength among the different study groups. Altogether, the results suggest that the ex vivo model can allow further understanding of the relationship between biochemical changes within the hydrogel and their impact on the hydrogel's mechanical properties.
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Cartilagem Articular/metabolismo , Diferenciação Celular , Condrócitos/metabolismo , Condrogênese , Hidrogéis/química , Células-Tronco Mesenquimais/metabolismo , Engenharia Tecidual , Animais , Cartilagem Articular/citologia , Condrócitos/citologia , Técnicas de Cocultura , Células-Tronco Mesenquimais/citologia , CoelhosRESUMO
OBJECTIVE: Improve 19F magnetic resonance imaging uniformity of perfluorocarbon (PFC)-labeled cells by using a secondary inductive resonator tuned to 287 MHz to enhance the induced radio frequency (RF) magnetic field (B1) at 7.05 T. MATERIALS AND METHODS: Following Faraday's induction law, the sign of induced B1 made by the secondary resonator can be changed depending on the tuning of the resonator. A secondary resonator located on the opposite side of the phantom of the 19F surface coil can be shown to enhance or subtract the induced B1 field, depending upon its tuning. RESULTS: The numerical simulation results of rotating transmit B1 magnitude (|B 1 + |) and corresponding experimental 19F images were compared without and with the secondary resonator. With the secondary resonator tuned to 287 MHz, improvements of |B 1 + | and 19F image uniformity were demonstrated. The use of the secondary resonator improved our ability to visualize transplanted cell location non-invasively over a period of 6 weeks. CONCLUSION: The secondary resonator tuned to enhance the induced B1 results in improved image uniformity in a pre-clinical application, enabling cell tracking of PFC-labeled cells with the secondary resonator.
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Rastreamento de Células/métodos , Imagem por Ressonância Magnética de Flúor-19 , Flúor/química , Campos Magnéticos , Transplante de Células-Tronco , Animais , Desenho de Equipamento , Fluorocarbonos , Camundongos , Modelos Teóricos , Imagens de Fantasmas , Ondas de Rádio , Razão Sinal-RuídoRESUMO
Calculated panel reactive antibody (cPRA) represents possibility of encountering an incompatible donor for organ transplant candidates and has gradually replaced traditional PRA as a measurement of sensitization level. We tested two cPRA calculation methods on a cohort of renal candidate (n = 613). HLA typing of 563 Chinese deceased renal donors was used to estimate allele and haplotype frequencies of Hong Kong donor pool. The OPTN formula was adopted to generate cPRA (cPRA (freq)). We also incorporated a computer script to compare unacceptable antigens of patients against HLA phenotype of donors. The cPRA based on historical donor filtering was the percentage of filter out count over total number of donors (cPRA (filter)). Values of cPRA (freq) and cPRA (filter) showed almost perfect agreement with Lin's correlation coefficient equal to 1.000. SD of bias was 0.6 cPRA point. Limit of agreement was 0.9 to -1.5 points difference. Furthermore, the poor agreement between our in-house cPRA and values from other online calculators indicated the necessity to use local population data for accurate cPRA calculation. Built-in donor filtering method was more practicable for Hong Kong due to factors such as cost and flexibility. An on-going donor pool can reflect population allele frequencies and permits efficient periodic update of cPRA.
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Seleção do Doador/métodos , Antígenos HLA/imunologia , Isoanticorpos/sangue , Transplante de Rim/mortalidade , Sistema de Registros , Obtenção de Tecidos e Órgãos/métodos , Estudos de Coortes , Feminino , Rejeição de Enxerto , Sobrevivência de Enxerto , Teste de Histocompatibilidade/métodos , Hong Kong , Humanos , Transplante de Rim/efeitos adversos , Transplante de Rim/métodos , Masculino , Estudos Retrospectivos , Medição de Risco , Análise de Sobrevida , Imunologia de TransplantesRESUMO
This study aims to reveal the impact of semi-mandatory non-financial disclosure requirements on corporate ESG performance and its mechanism. Utilizing the "comply or explain" semi-mandatory ESG disclosure requirement implemented by the Hong Kong Exchanges and Clearing Limited (HKEx) of China in 2016 as a quasi-experiment, and adopting the difference-in-differences identification strategy, this paper finds that semi-mandatory non-financial disclosure requirements can significantly enhance corporate ESG performance. Through mechanism analysis, it is found that semi-mandatory non-financial disclosure requirement promotes firms' ESG performance by suppressing the myopic behavior of corporate management and improving the quality of corporate internal control. Through heterogeneity analysis, it is found that semi-mandatory non-financial disclosure requirements have a greater effect on the ESG performance of firms with high institutional investor attention and non-polluting firms, and a smaller effect on firms with executives with overseas experience.
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Microphysiological systems (MPS), also known as miniaturized physiological environments, have been engineered to create and study functional tissue units capable of replicating organ-level responses in specific contexts. The MPS has the potential to provide insights about the safety, characterization, and effectiveness of medical products that are different and complementary to insights gained from traditional testing systems, which can help facilitate the transition of potential medical products from preclinical phases to clinical trials, and eventually to market. While many MPS are versatile and can be used in various applications, most of the current applications have primarily focused on drug discovery and testing. Yet, there is a limited amount of research available that demonstrates the use of MPS in assessing biological products such as cellular and gene therapies. This review paper aims to address this gap by discussing recent technical advancements in MPS and their potential for assessing biological products. We further discuss the challenges and considerations involved in successful translation of MPS into mainstream product testing.
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Produtos Biológicos , Sistemas Microfisiológicos , Descoberta de DrogasRESUMO
Tourism efficiency has become an important role in promoting tourism competitiveness and driving sustainable development. It is particularly important to identify and agnalyze the factors and mechanisms that affect efficiency. This paper firstly evaluates the tourism efficiency of 11 coastal provinces regions in China from 2010 to 2020 by using the DEA-BBC model that includes undesirable outputs. After that, it investigates the internal driving mechanism of the efficiency change through the Malmquist index and its decomposition. Finally, it analyzes the external influencing elements of tourist efficiency by the Tobit model. The results show that: (1) Although the average value of the tourism efficiency was changed from 0.727 to 0.707, it does not achieve the target. Its trend shows fluctuating from 2010-2020, which indicates that the tourism efficiency of most provincial regions is not optimal. The main factor that restricts tourism efficiency is scale efficiency. (2) By analyzing the dynamic trend, it is found that the average increase of technical efficiency is 14.0%, the average increase of technical change is 9.5%, and the average increase of MI index is 25.4%. It indicates that the overall tourism efficiency of 11 coastal provinces region in China is on the rise. (3) The spatial difference of tourism efficiency is significant, but there is no obvious spatial correlation. (4) The influencing factors of tourism efficiency are consumer demand, industrial structure, labor force and urbanization.
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Turismo , China , Humanos , Desenvolvimento Sustentável/tendências , Modelos TeóricosRESUMO
Process models are a growing tool for pharmaceutical manufacturing process design and control. The Industry 4.0 paradigm promises to increase the amount of data available to understand manufacturing processes. Tools such as Artificial Intelligence (AI) might accelerate process development and allow better predictions of process trajectories. Several examples of process improvements realized through the application of process models have been shown in lyophilization, chromatography, fluid bed drying, bioreactor control, continuous direct compression, and wet granulation. An important consideration of implementing a process model is determining the impact of the model on the quality of the product and the risks associated with model maintenance over the product lifecycle. Several regulatory documents address risk-based considerations for process models. This work discusses existing risk-based frameworks for model validation and lifecycle maintenance that could aid the adoption of process models in pharmaceutical manufacturing. Hypothetical case studies illustrate the implications of applying a model risk framework to facilitate model validation and lifecycle maintenance in the manufacture of pharmaceuticals and biological products.
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There is a need for better predictive models of the human immune system to evaluate safety and efficacy of immunomodulatory drugs and biologics for successful product development and regulatory approvals. Current in vitro models, which are often tested in two-dimensional (2D) tissue culture polystyrene, and preclinical animal models fail to fully recapitulate the function and physiology of the human immune system. Microphysiological systems (MPSs) that can model key microenvironment cues of the human immune system, as well as of specific organs and tissues, may be able to recapitulate specific features of the in vivo inflammatory response. This minireview provides an overview of MPS for modeling lymphatic tissues, immunity at tissue interfaces, inflammatory diseases, and the inflammatory tumor microenvironment in vitro and ex vivo. Broadly, these systems have utility in modeling how certain immunotherapies function in vivo, how dysfunctional immune responses can propagate diseases, and how our immune system can combat pathogens.
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Imunoterapia , Sistemas Microfisiológicos , Animais , Humanos , Microambiente TumoralRESUMO
Mesenchymal stromal cells (MSCs) continue to be proposed for clinical investigation to treat myriad diseases given their purported potential to stimulate endogenous regenerative processes, such as angiogenesis. However, MSC functional heterogeneity has hindered clinical success and still poses a substantial manufacturing challenge from a product quality control perspective. Here, a quantitative bioassay based on an enhanced-throughput is described, microphysiological system (MPS) to measure the specific bioactivity of MSCs to stimulate angiogenesis as a potential measure of MSC potency. Using this novel bioassay, MSCs derived from multiple donors at different passages are co-cultured with human umbilical vein endothelial cells and exhibit significant heterogeneity in angiogenic potency between donors and cell passage. Depending on donor source and cellular passage number, MSCs varied in their ability to stimulate tip cell dominant or stalk cell dominant phenotypes in angiogenic sprout morphology which correlated with expression levels of hepatocyte growth factor (HGF). These findings suggest that MSC angiogenic bioactivity may be considered as a possible potency attribute in MSC quality control strategies. Development of a reliable and functionally relevant potency assay for measuring clinically relevant potency attributes of MSCs will help to improve consistency in quality and thereby, accelerate clinical development of these cell-based products.
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Mesenchymal stromal cells (MSCs) continue to be proposed for use in clinical trials to treat various diseases due to their therapeutic potential to pleiotropically influence endogenous regenerative processes, such as vasculogenesis. However, the functional heterogeneity of MSCs has hampered their clinical success and poses a significant manufacturing challenge with respect to MSC quality control. Here, we evaluated and qualified a quantitative bioassay based on an enhanced-throughput, microphysiological system to measure the specific paracrine bioactivity of MSCs to stimulate vasculogenesis as a measure of MSC potency. Using this novel bioassay, MSCs derived from multiple donors at different passages were co-cultured with human umbilical vein endothelial cells (HUVECs) and exhibited significant heterogeneity in vasculogenic potency between donors and cell passage. Using our microphysiological system (MPS)-based platform, we demonstrated that variations in MSC vasculogenic bioactivity were maintained when assayed across laboratories and operators. The differences in MSC vasculogenic bioactivity were also correlated with the baseline expression of several genes involved in vasculogenesis (hepatocyte growth factor (HGF), angiopoietin-1 (ANGPT)) or the production of matricellular proteins (fibronectin (FN), insulin-like growth factor-binding protein 7 (IGFBP7)). These findings emphasize the significant functional heterogeneity of MSCs in vasculogenic bioactivity and suggest that changes in baseline gene expression of vasculogenic or matricellular protein genes during manufacturing may affect this bioactivity. The development of a reliable and functionally relevant potency assay for measuring the specific vasculogenic bioactivity of manufactured MSCs will help to reliably assure their quality when used in appropriate clinical trials.
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Células-Tronco Mesenquimais , Humanos , Células-Tronco Mesenquimais/metabolismo , Técnicas de Cocultura , Diferenciação Celular , Células Endoteliais da Veia Umbilical Humana/metabolismo , Bioensaio , Células Cultivadas , Proliferação de CélulasRESUMO
Focal adhesions are critical to a number of cellular processes that involve mechanotransduction and mechanical interaction with the cellular environment. The growth and strengthening of these focal adhesions is dependent on the interaction between talin and vinculin. This study investigates said interaction and how vinculin activation influences it. Using molecular dynamics, the interaction between talin's vinculin binding site (VBS) and vinculin's domain 1 (D1) is simulated both before and after vinculin activation. The simulations of VBS binding to vinculin before activation suggest the proximity of the vinculin tail to D1 prevents helical movement in D1 and thus prevents binding of VBS. In contrast, interaction of VBS with activated vinculin shows the possibility of complete VBS insertion into D1. In the simulations of both activated and autoinhibited vinculin where VBS fails to fully bind, VBS demonstrates significant hydrophobic interaction with surface residues in D1. These interactions link VBS to D1 even without its proper insertion into the hydrophobic core. Together these simulations suggest VBS binds to vinculin with the following mechanism: 1), VBS links to D1 via surface hydrophobic interactions; 2), vinculin undergoes activation and D1 is moved away from the vinculin tail; 3), helices in D1 undergo conformational change to allow VBS binding; and 4), VBS inserts itself into the hydrophobic core of D1.
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Citoesqueleto/química , Simulação de Dinâmica Molecular , Talina/química , Vinculina/química , Sítios de Ligação , Cristalografia por Raios X , Adesões Focais/fisiologia , Interações Hidrofóbicas e Hidrofílicas , Mecanotransdução Celular/fisiologia , Ligação Proteica/fisiologia , Conformação Proteica , Estrutura Terciária de Proteína/fisiologiaRESUMO
Osteochondral defects present a unique clinical challenge due to their combination of phenotypically distinct cartilage and bone, which require specific, stratified biochemical cues for tissue regeneration. Furthermore, the articular cartilage exhibits significantly worse regeneration than bone due to its largely acellular and avascular nature, prompting significant demand for regenerative therapies. To address these clinical challenges, we have developed a bilayered, modular hydrogel system that enables the click functionalization of cartilage- and bone-specific biochemical cues to each layer. In this system, the crosslinker poly(glycolic acid)-poly(ethylene glycol)-poly(glycolic acid)-di(but-2-yne-1,4-dithiol) (PdBT) was click conjugated with either a cartilage- or bone-specific peptide sequence of interest, and then mixed with a suspension of thermoresponsive polymer and mesenchymal stem cells (MSCs) to generate tissue-specific, cell-encapsulated hydrogel layers targeting the cartilage or bone. We implanted bilayered hydrogels in rabbit femoral condyle defects and investigated the effects of tissue-specific peptide presentation and cell encapsulation on osteochondral tissue repair. After 12 weeks implantation, hydrogels with a chondrogenic peptide sequence produced higher histological measures of overall defect filling, cartilage surface regularity, glycosaminoglycan (GAG)/cell content of neocartilage and adjacent cartilage, and bone filling and bonding compared to non-chondrogenic hydrogels. Furthermore, MSC encapsulation promoted greater histological measures of overall defect filling, cartilage thickness, GAG/cell content of neocartilage, and bone filling. Our results establish the utility of this click functionalized hydrogel system for in vivo repair of the osteochondral unit. STATEMENT OF SIGNIFICANCE: Osteochondral repair requires mimicry of both cartilage- and bone-specific biochemical cues, which are highly distinct. While traditional constructs for osteochondral repair have mimicked gross compositional differences between the cartilage and bone in mineral content, mechanical properties, proteins, or cell types, few constructs have recapitulated the specific biochemical cues responsible for the differential development of cartilage and bone. In this study, click biofunctionalized, bilayered hydrogels produced stratified presentation of developmentally inspired peptide sequences for chondrogenesis and osteogenesis. This work represents, to the authors' knowledge, the first application of bioconjugation chemistry for the simultaneous repair of bone and cartilage tissue. The conjugation of tissue-specific peptide sequences successfully promoted development of both cartilage and bone tissues in vivo.
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Cartilagem Articular , Hidrogéis , Animais , Condrogênese , Peptídeos , Coelhos , Engenharia TecidualRESUMO
This work investigated the effect of poly(l-lysine) (PLL) molecular weight and concentration on chondrogenesis of cocultures of mesenchymal stem cells (MSCs) and articular chondrocytes (ACs) in PLL-loaded hydrogels. An injectable dual-network hydrogel composed of a poly(N-isopropylacrylamide)-based synthetic thermogelling macromer and a chondroitin sulfate-based biological network was leveraged as a model to deliver PLL and encapsulate the two cell populations. Incorporation of PLL into the hydrogel did not affect the hydrogel's swelling properties and degradation characteristics, nor the viability of encapsulated cells. Coculture groups demonstrated higher type II collagen expression compared to the MSC monoculture group. Expression of hypertrophic phenotype was also limited in the coculture groups. Histological analysis indicated that the ratio of MSCs to ACs was an accurate predictor of the degree of long-term chondrogenesis, while the presence of PLL was shown to have a more substantial short-term effect. Altogether, this study demonstrates that coculturing MSCs with ACs can greatly enhance the chondrogenicity of the overall cell population and offers a platform to further elucidate the short- and long-term effect of polycationic factors on the chondrogenesis of MSC and AC cocultures.
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Cartilagem Articular , Células-Tronco Mesenquimais , Diferenciação Celular , Células Cultivadas , Condrócitos , Condrogênese , Técnicas de Cocultura , Hidrogéis , PolilisinaRESUMO
In this study, we describe the synthesis and characterization of a biosynthetic hydrogel system that consists of a thermally responsive macromer and biological cross-linkers. By combining a poly(N-isopropylacrylamide)-based thermogelling macromer with epoxy pendant groups and chondroitin sulfate cross-linkers that are modified to contain either hydrazide or N-hydroxysuccinimide pendant groups, we successfully fabricated a system that undergoes gelation when the temperature is raised from room temperature to 37 °C and is further stabilized via covalent links between the macromers. The anionic charge on chondroitin sulfate contributed to a high degree of gel swelling, while the cross-linking reaction between the macromers prevented post-formation syneresis. The rate of degradation of CS-cross-linked hydrogels was dependent on the degree of substitution of hydrazide-modified chondroitin sulfate cross-linkers. A higher molar content of chondroitin sulfate led to a greater osmotic pressure within the hydrogel and thus a higher compressive modulus. On the other hand, excessive amounts of chondroitin sulfate caused time-dependent cytotoxicity, as confirmed by a leachables cytocompatibility study. Overall, the system described in this study provides a versatile platform to synthesize hydrogels with differing combinations of compressive moduli and rates of degradation, which is achievable by varying the degree of substitution of hydrazide groups on CS-based cross-linkers.
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The Hong Kong Renal Registry (HKRR) is an electronic paperless registry that services as database for patients on various renal replacement therapies in the territory. The database consists of demographic data, dialysis and transplant treatments, complications, and inquiries and reports. The HKRR can be helpful for individual patient's management, for renal center management, and for territory-wide management.
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Falência Renal Crônica/terapia , Diálise Peritoneal , Sistema de Registros , Previsões , Planejamento em Saúde/métodos , Planejamento em Saúde/tendências , Hong Kong , HumanosRESUMO
Heterogeneity in cell function has presented a significant hurdle to the successful clinical translation of many cellular therapies. Current techniques for assessing cell quality and the effects of microenvironmental cues and manufacturing processes on cell behavior often inadequately address heterogeneity due to issues such as population versus single-cell measurements and the therapeutic relevance and throughput/robustness of the assay. Due to the well-established relationship between morphology and cellular function, morphological profiling has become increasingly utilized to better understand functional heterogeneity and its impact on therapeutic development. In this review, we introduce an emerging field we term functionally-relevant morphological profiling with great potential to improve our understanding of cellular heterogeneity through discovering novel quality attributes, optimizing manufacturing, and screening drugs/biomaterials.
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Forma Celular , Técnicas Citológicas/métodos , Processamento de Imagem Assistida por Computador/métodos , Microscopia/métodos , Imagem Óptica/métodos , Técnicas de Cultura de Células/métodos , Terapia Baseada em Transplante de Células e Tecidos/métodos , Humanos , Tecnologia Farmacêutica/métodosRESUMO
Multipotent stromal cells (MSCs) are an attractive cell source for bone and cartilage tissue repair strategies. However, the functional heterogeneity of MSCs derived from different donors and manufacturing conditions has limited clinical translation, emphasizing the need for improved methods to assess MSC chondrogenic capacity. We used functionally relevant morphological profiling to dynamically monitor emergent morphological phenotypes of chondrogenically induced MSC aggregates to identify morphological features indicative of MSC chondrogenesis. Toward this goal, we characterized the morphology of chondrogenically stimulated MSC aggregates from eight different human cell-lines at multiple passages and demonstrated that MSC aggregates exhibited unique morphological dynamics that were both cell line- and passage-dependent. This variation in 3D morphology was shown to be informative of long-term MSC chondrogenesis based on multiple quantitative functional assays. We found that the specific morphological features of spheroid area, radius, minimum feret diameter, and minor axis length to be strongly correlated with MSC chondrogenic synthetic activity but not gene expression as early as day 4 in 3D culture. Our high-throughput, nondestructive approach could potentially serve as a tool to identify MSC lines with desired chondrogenic capacity toward improving manufacturing strategies for MSC-based cellular products for cartilage tissue repair. Stem Cells Translational Medicine 2018;1-12.
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Células-Tronco Mesenquimais/metabolismo , Esferoides Celulares/metabolismo , Transcriptoma , Células da Medula Óssea/citologia , Técnicas de Cultura de Células , Diferenciação Celular , Células Cultivadas , Condrogênese , Análise por Conglomerados , Humanos , Células-Tronco Mesenquimais/citologia , Fenótipo , Análise de Componente Principal , Esferoides Celulares/citologiaRESUMO
After myocardial infarction (MI), the scar tissue contributes to ventricular dysfunction by electrically uncoupling viable cardiomyocytes in the infarct region. Injection of a conductive hydrogel could not only provide mechanical support to the infarcted region, but also synchronize contraction and restore ventricular function by electrically connecting isolated cardiomyocytes to intact tissue. Methods: We created a conductive hydrogel by introducing graphene oxide (GO) nanoparticles into oligo(poly(ethylene glycol) fumarate) (OPF) hydrogels. The hydrogels were characterized by AFM and electrochemistry workstation. A rat model of myocardial infarction was used to investigate the ability of OPF/GO to improve cardiac electrical propagation in the injured heart in vivo. Echocardiography (ECHO) was used to evaluate heart function 4 weeks after MI. Ca2+ imaging was used to visualize beating cardiomyocytes (CMs). Immunofluorescence staining was used to visualize the expression of cardiac-specific markers. Results: OPF/GO hydrogels had semiconductive properties that were lacking in pure OPF. In addition, the incorporation of GO into OPF hydrogels could improve cell attachment in vitro. Injection of OPF/GO 4 weeks after myocardial infarction in rats enhanced the Ca2+ signal conduction of cardiomyocytes in the infarcted region in comparison with PBS or OPF alone. Moreover, the injection of OPF/GO hydrogel into the infarct region enhanced the generation of cytoskeletal structure and intercalated disc assembly. Echocardiography analysis showed improvement in load-dependent ejection fraction/fractional shortening of heart function 4 weeks after injection. Conclusions: We prepared a conductive hydrogel (OPF/GO) that provide mechanical support and biological conduction in vitro and in vivo. We found that injected OPF/GO hydrogels can provide mechanical support and electric connection between healthy myocardium and the cardiomyocytes in the scar via activating the canonical Wnt signal pathway, thus upregulating the generation of Cx43 and gap junction associated proteins. Injection of OPF/GO hydrogel maintained better heart function after myocardial infarction than the injection of a nonconductive polymer.