RESUMO
In a myocardial infarction, blood supply to the left ventricle is abrogated due to blockage of one of the coronary arteries, leading to ischemia, which further triggers the generation of reactive oxygen species (ROS). These sequential processes eventually lead to the death of contractile cells and affect the integrity of blood vessels, resulting in the formation of scar tissue. A new heart therapy comprised of cardiac implants encapsulated within an injectable extracellular matrix-gold nanoparticle composite hydrogel is reported. The particles on the collagenous fibers within the hydrogel promote fast transfer of electrical signal between cardiac cells, leading to the functional assembly of the cardiac implants. The composite hydrogel is shown to absorb reactive oxygen species in vitro and in vivo in mice ischemia reperfusion model. The reduction in ROS levels preserve cardiac tissue morphology and blood vessel integrity, reduce the scar size and the inflammatory response, and significantly prevent the deterioration of heart function.
Assuntos
Hidrogéis/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Nanocompostos/administração & dosagem , Próteses e Implantes , Espécies Reativas de Oxigênio/metabolismo , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Ouro , Coração/efeitos dos fármacos , Coração/fisiologia , Hidrogéis/administração & dosagem , Hidrogéis/metabolismo , Injeções , Masculino , Nanopartículas Metálicas , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
One of the strategies for heart regeneration includes cell delivery to the defected heart. However, most of the injected cells do not form quick cell-cell or cell-matrix interactions, therefore, their ability to engraft at the desired site and improve heart function is poor. Here, the use of a microfluidic system is reported for generating personalized hydrogel-based cellular microdroplets for cardiac cell delivery. To evaluate the system's limitations, a mathematical model of oxygen diffusion and consumption within the droplet is developed. Following, the microfluidic system's parameters are optimized and cardiac cells from neonatal rats or induced pluripotent stem cells are encapsulated. The morphology and cardiac specific markers are assessed and cell function within the droplets is analyzed. Finally, the cellular droplets are injected to mouse gastrocnemius muscle to validate cell retention, survival, and maturation within the host tissue. These results demonstrate the potential of this approach to generate personalized cellular microtissues, which can be injected to distinct regions in the body for treating damaged tissues.
Assuntos
Transplante de Células , Terapia Baseada em Transplante de Células e Tecidos , Coração , Hidrogéis , Miocárdio , Animais , Transplante de Células/métodos , Terapia Baseada em Transplante de Células e Tecidos/métodos , Injeções , Camundongos , Microfluídica , Modelos Biológicos , Miocárdio/citologia , RatosRESUMO
Generation of thick vascularized tissues that fully match the patient still remains an unmet challenge in cardiac tissue engineering. Here, a simple approach to 3D-print thick, vascularized, and perfusable cardiac patches that completely match the immunological, cellular, biochemical, and anatomical properties of the patient is reported. To this end, a biopsy of an omental tissue is taken from patients. While the cells are reprogrammed to become pluripotent stem cells, and differentiated to cardiomyocytes and endothelial cells, the extracellular matrix is processed into a personalized hydrogel. Following, the two cell types are separately combined with hydrogels to form bioinks for the parenchymal cardiac tissue and blood vessels. The ability to print functional vascularized patches according to the patient's anatomy is demonstrated. Blood vessel architecture is further improved by mathematical modeling of oxygen transfer. The structure and function of the patches are studied in vitro, and cardiac cell morphology is assessed after transplantation, revealing elongated cardiomyocytes with massive actinin striation. Finally, as a proof of concept, cellularized human hearts with a natural architecture are printed. These results demonstrate the potential of the approach for engineering personalized tissues and organs, or for drug screening in an appropriate anatomical structure and patient-specific biochemical microenvironment.
RESUMO
Despite incremental improvements in the field of tissue engineering, no technology is currently available for producing completely autologous implants where both the cells and the scaffolding material are generated from the patient, and thus do not provoke an immune response that may lead to implant rejection. Here, a new approach is introduced to efficiently engineer any tissue type, which its differentiation cues are known, from one small tissue biopsy. Pieces of omental tissues are extracted from patients and, while the cells are reprogrammed to become induced pluripotent stem cells, the extracellular matrix is processed into an immunologically matching, thermoresponsive hydrogel. Efficient cell differentiation within a large 3D hydrogel is reported, and, as a proof of concept, the generation of functional cardiac, cortical, spinal cord, and adipogenic tissue implants is demonstrated. This versatile bioengineering approach may assist to regenerate any tissue and organ with a minimal risk for immune rejection.
Assuntos
Hidrogéis/química , Próteses e Implantes , Animais , Diferenciação Celular , Reprogramação Celular , Células Endoteliais/citologia , Células Endoteliais/imunologia , Células Endoteliais/transplante , Matriz Extracelular/imunologia , Matriz Extracelular/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/citologia , Miócitos Cardíacos/imunologia , Miócitos Cardíacos/transplante , Omento/citologia , Omento/imunologia , Omento/metabolismo , Suínos , Engenharia Tecidual , Alicerces Teciduais , Transplante AutólogoRESUMO
Two dehydrogenases, cellobiose dehydrogenase from Corynascus thermophilus and pyranose dehydrogenase from Agaricus meleagris, were displayed for the first time on the surface of Saccharomyces cerevisiae using the yeast surface display system. Surface displayed dehydrogenases were used in a microbial fuel cell and generated high power outputs. Surface displayed cellobiose dehydrogenase has demonstrated a midpoint potential of -28mV (vs. Ag/AgCl) at pH=6.5 and was used in a mediator-less anode compartment of a microbial fuel cell producing a power output of 3.3µWcm(-2) using lactose as fuel. Surface-displayed pyranose dehydrogenase was used in a microbial fuel cell and generated high power outputs using different substrates, the highest power output that was achieved was 3.9µWcm(-2) using d-xylose. These results demonstrate that surface displayed cellobiose dehydrogenase and pyranose dehydrogenase may successfully be used in microbial bioelectrochemical systems.
Assuntos
Fontes de Energia Bioelétrica/microbiologia , Desidrogenases de Carboidrato/genética , Desidrogenases de Carboidrato/metabolismo , Saccharomyces cerevisiae/genética , Adsorção , Agaricus/enzimologia , Eletroquímica , Eletrodos , Azul de Metileno/metabolismo , Oxirredução , Sordariales/enzimologia , Águas Residuárias/microbiologiaRESUMO
In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.