Spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells maintain pluripotency of stem cells by regulating hypoxia-inducible factors

BACKGROUND: Spontaneous spheroid culture is a novel three-dimensional (3D) culture strategy for the rapid and efficient selection of progenitor cells. The objectives of this study are to investigate the pluripotency and differentiation capability of spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells (AB-MSCs); compare the advantages of spontaneous spheroids to those of mechanical spheroids; and explore the mechanisms of stemness enhancement during spheroid formation from two-dimensional (2D) cultured cells. METHODS: AB-MSCs were isolated from the alveolar bones of C57BL/6 J mice. Spontaneous spheroids formed in low-adherence specific culture plates. The stemness, proliferation, and multi-differentiation capacities of spheroids and monolayer cultures were investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, alkaline phosphatase (ALP) activity, and oil-red O staining. The pluripotency difference between the spontaneous and mechanical spheroids was analyzed using RT-qPCR. Hypoxia-inducible factor (HIFs) inhibition experiments were performed to explore the mechanisms of stemness maintenance in AB-MSC spheroids. RESULTS: AB-MSCs successfully formed spontaneous spheroids after 24 h. AB-MSC spheroids were positive for MSC markers and pluripotency markers (Oct4, KLF4, Sox2, and cMyc). Spheroids showed higher Ki67 expression and lower Caspase3 expression at 24 h. Under the corresponding conditions, the spheroids were successfully differentiated into osteogenic and adipogenic lineages. AB-MSC spheroids can induce neural-like cells after neurogenic differentiation. Higher expression of osteogenic markers, adipogenic markers, and neurogenic markers (NF-M, NeuN, and GFAP) was found in spheroids than in the monolayer. Spontaneous spheroids exhibited higher stemness than mechanical spheroids did. HIF-1α and HIF-2α were remarkably upregulated in spheroids. After HIF-1/2α-specific inhibition, spheroid formation was significantly reduced. Moreover, the expression of the pluripotency genes was suppressed. CONCLUSIONS: Spontaneous spheroids from AB-MSCs enhance stemness and pluripotency. HIF-1/2α plays an important role in the stemness regulation of spheroids. AB-MSC spheroids exhibit excellent multi-differentiation capability, which may be a potent therapy for craniomaxillofacial tissue regeneration.

Estudo do composto STX140, um análogo do estradiol, em linhagens de melanoma humano / STX140 compound study in human melanoma

O câncer de pele pode ser classificado como não melanoma e melanoma. O melanoma apresenta baixa incidência entre os cânceres de pele, porém é a forma mais letal e é considerado um dos tipos mais resistentes ao tratamento. Devido à infiltração de células malignas nos tecidos, vasos linfáticos e vasos sanguíneos, o melanoma invade e se espalha rapidamente. Suas metástases são frequentemente localizadas em linfonodos, cérebro, fígado e outros órgãos. Melanomas metastáticos abrigam múltiplas mutações gênicas e muitos tumores apresentam resistência aos tratamentos, como por exemplo com inibidores BRAF, devido à mutações e ativação de vias paralelas. Ou seja, existe uma necessidade clara da busca de novas opções de tratamento. Em trabalho realizado por nosso grupo, Massaro et al mostraram que o derivado de estradiol 2- Metoxiestradiol induz apoptose em células de melanoma e senescência. Neste sentido, o composto STX140, (um análogo do estradiol com biodisponibilidade superior), que já se mostrou eficaz no combate ao câncer de mama em diversos estudos in vitro e in vivo, será então avaliado para sua ação no melanoma de forma inédita. Este trabalho teve como principal objetivo explorar a ação antitumoral em células de melanoma do composto STX140, especialmente a indução de senescência. Utilizando a cultura de células de melanoma foram realizados os ensaios de: viabilidade celular - IC50, formação de colônias, análise do ciclo celular e caracterização de morte celular por citometria de fluxo, ensaio In vitro scratch, coloração para ß-galactosidase, PCR quantitativo e ELISA. Os resultados mostraram que o composto STX140: diminui a viabilidade celular, inibe a proliferação, formação de colônias e migração em linhagens de melanoma (não resistentes e resistentes ao vemurafenibe, inibidor de BRAF). Além do mais, o composto atuou diminuindo a secreção da interleucina pró-tumoral IL-8 em células resistentes. O STX140 induziu senescência nas células de melanoma que foram positivas para ß-galactosidase, também havendo aumento da expressão de genes chave de vias de senescência (CDKN1A e GADD45A) nas células de melanoma resistentes tratadas com o composto. Em conclusão, o STX140 mostrou ter um potencial antitumoral contra o melanoma, diminuindo sua viabilidade celular, inibindo sua proliferação e migração, induzindo senescência, diminuindo a secreção de interleucina pró- tumoral, com efeito mais acentuado nas linhagens de melanoma resistente

Skin cancer can be classified as non-melanoma and melanoma. Melanoma has a low incidence among skin cancers, but it is the most lethal form and is considered one of the most resistant to treatment. Due to the infiltration of malignant cells into tissues, lymphatic vessels and blood vessels, melanoma invades and spreads rapidly. Its metastases are often located in lymph nodes, brain, liver and other organs. Metastatic melanomas presents multiple gene mutations and many tumors are resistant to treatments, such as with BRAF inhibitors, due to mutations and activation of parallel pathways. In other words, there is a clear need to search for new treatment options. In work carried out by our group, Massaro et al showed that the estradiol derivative 2- Methoxyestradiol induces apoptosis in melanoma cells and senescence. In this sense, the compound STX140, (an estradiol analogue with superior bioavailability), which has already been shown to be effective against breast cancer in vitro and in vivo studies will be then evaluated for its action on melanoma. The main objective of this work is to explore the antitumor action of the compound STX140 in melanoma cells, especially the induction of senescence. Using the melanoma cell culture the following assays were performed: cell viability - IC50, clonogenic, cell cycle analysis and cell death characterization by flow cytometry, wound assay, staining for ß-galactosidase, quantitative PCR and ELISA. Preliminary data from this work showed that the compound STX140: decreases cell viability, inhibits proliferation, colony formation and migration in melanoma cell lines (non-resistant and resistant to vemurafenib, BRAF inhibitor). It also decreased the secretion of pro-tumor interleukin IL-8 in resistant cells. STX140 induced senescence in melanoma cells, that were positive for ß-galactosidase, and there was also increased expression of key genes of senescence pathways (CDKN1A and GADD45A) in resistant melanoma cells treated with the compound. In conclusion, STX140 has been shown to have antitumor potential against melanoma, decreasing its cell viability, inhibiting its proliferation and migration, inducing senescence, decreasing pro-tumor interleukin secretion, with a more pronounced effect on resistant melanoma cell lines

Formulation and evaluation of the vascular endothelial growth factor loaded polycaprolactone nanoparticles

Abstract In an attempt to increase molecular stability and provide controlled release, vascular endothelial growth factor (VEGF) was encapsulated into polycaprolactone (PCL) nanoparticles. Both VEGF-free and VEGF-loaded PCL nanoparticles were formulated by w/o/w double emulsion of the dichloromethane-water system in the presence of polyvinyl alcohol (PVA) and rat serum albumin. To achieve the optimal formulation concerning particle size and monodispersity, studies were carried out with different formulation parameters, including PVA concentration, homogenization time and rate. Scanning electron microscopy and dynamic light scattering analysis showed respectively that particles had a spherical shape with a smooth surface and particle size varying between 58.68-751.9 nm. All of the formulations were negatively charged according to zeta potential analysis. In vitro release study was performed in pH 7.4 phosphate-buffered saline at 37°C and released VEGF amount was measured by enzyme-linked immunosorbent assay (ELISA) method. At the end of the 35th day, 10% of total encapsulated VEGF was released with a sustained-release profile, which fitted the Korsmeyer-Peppas kinetic model. The bioactivation of the nanoparticles was evaluated using XTT and ELISA methods. As a result, the released VEGF was biologically active and also VEGF loaded PCL nanoparticles enhanced proliferation of the human umbilical vein endothelial cells in cell culture.

Synthesis and characterization of chitosan-PVA hydrogel containing PEGylated recombinant epidermal growth factor on cell culture for wound healing substitute

Abstract The aim of the current study was to assess the physicochemical characteristics and wound healing activity of chitosan-polyvinyl alcohol (PVA) crosslinked hydrogel containing recombinant human epidermal growth factor (rh-EGF) or recombinant mouse epidermal growth factor (rm-EGF). The hydrogels were prepared and analyses were made of the morphological properties, viscosity, water absorption capacity, mechanical and bio-adhesive properties. The viscosity of the formulations varied between 14.400 - 48.500 cPs, with the greatest viscosity values determined in K2 formulation. F2 formulation showed the highest water absorption capacity. According to the studies of the mechanical properties, H2 formulation (0.153±0.018 N.mm) showed the greatest adhesiveness and E2 (0.245±0.001 mj/cm2) formulation, the highest bio-adhesion values. Hydrogels were cytocompatible considering in vitro cell viability values of over 76% on human keratinocyte cells (HaCaT, CVCL-0038) and of over 84% on human fibroblast cells (NIH 3T3, CRL-1658) used as a model cell line. According to the BrdU cell proliferation results, B1 (197.82±2.48%) formulation showed the greatest NIH 3T3 and C1 (167.43±5.89%) formulation exhibited the highest HaCaT cell proliferation ability. In addition, the scratch closure assay was performed to assess the wound healing efficiency of formulation and the results obtained in the study showed that F2 formulation including PEGylated rh-EGF had a highly effective role.

Establecimiento e implementación de un protocolo simplificado de expansión y cultivo de Células Madre de Pulpa Dental Humana (DPSCh) / Estabelecimento e implementação de um protocolo simplificado para expansão e cultura de células-tronco da polpa dentária humana (DPSCh) / Establishing and implementing a simplified protocol for the expansion and culture of human dental pulp stem cells (hDPSCs)

Resumen Objetivos: Establecer e implementar un protocolo simplificado de extracción, aislamiento primario y cultivo de células madre derivadas de la pulpa dental humana (DPSCh). Analizar cuantitativamente y cualitativamente las células aisladas. Metodología: 10 terceros molares sanos donados por pacientes que concurrieron a la Facultad de Odontología, UdelaR y otorgaron su consentimiento escrito fueron procesados antes de las 48 hs. Se realizó la fractura de la pieza para la obtención del tejido pulpar y se procesó por el método explante. Se analizó viabilidad celular y expresión de marcadores por citometría de flujo en pasajes 4 y 12 y se corroboró mediante inmunocitoquímica. Resultados: Las células obtenidas presentaron una vitalidad mayor al 90% en todos los pasajes, observándose una morfología característica y expresión de marcadores de células madre mesenquimales CD90, C105, CD73, CD29 y 166 mediante citometría de flujo en ambos pasajes. Conclusiones: Se logró establecer un protocolo de aislamiento y expansión celular, con alta tasa de éxito de una población de DPSCh.

Resumo Objetivos: Estabelecer e implementar um protocolo simplificado para a extração, isolamento primário e cultura de células-tronco da polpa dentária humana (DPSCh). Analise as células isoladas quantitativa e qualitativamente. Metodologia: 10 terceiros molares saudáveis ​​doados por pacientes que frequentaram a Faculdade de Odontologia UdelaR e deram consentimento por escrito foram processados ​​antes de 48 horas. A fratura da peça foi realizada para obtenção do tecido pulpar e processada pelo método do explante. A viabilidade celular e a expressão do marcador foram analisadas por citometría de fluxo nas passagens 4 e 12 e confirmadas por inmunocitoquímica. Resultados: As células obtidas apresentaram viabilidade superior a 90% em todas as passagens, observando uma morfologia característica e expressão dos marcadores de células-tronco mesenquimais CD90, C105, CD73, CD29 e 166 por citometría de fluxo em ambas as passagens. Conclusões: Foi possível estabelecer um protocolo de isolamento celular, com alta taxa de sucesso e segurança para isolar o DPSCh.

Abstract Objectives: To establish and implement a simplified protocol for the extraction, primary isolation, and culture of human dental pulp stem cells (hDPSCs). To analyze the isolated cells quantitatively and qualitatively. Methodology: Ten healthy third molars were donated by patients who attended the School of Dentistry, UdelaR, and gave their written consent. The teeth were processed within 48 hours. The teeth were sectioned to obtain the pulp tissue and processed with the explant method. Cell viability and marker expression were analyzed by flow cytometry at passages 4 and 12 and verified by immunocytochemistry. Results: The cells obtained had a vitality greater than 90% in all passages. We found the characteristic morphology and the expression of CD90, C105, CD73, CD29 and 166 mesenchymal stem cell markers by flow cytometry in both passages. Conclusion: It was possible to establish a cell isolation protocol that is highly successful and safe to isolate hDPSC.

Magnetic hyperthermia therapy in glioblastoma tumor on-a-Chip model / Terapia de magneto-hipertermia no modelo de tumor de glioblastoma on-a-Chip

ABSTRACT Objective: To evaluate the magnetic hyperthermia therapy in glioblastoma tumor-on-a-Chip model using a microfluidics device. Methods: The magnetic nanoparticles coated with aminosilane were used for the therapy of magnetic hyperthermia, being evaluated the specific absorption rate of the magnetic nanoparticles at 300 Gauss and 305kHz. A preculture of C6 cells was performed before the 3D cells culture on the chip. The process of magnetic hyperthermia on the Chip was performed after administration of 20μL of magnetic nanoparticles (10mgFe/mL) using the parameters that generated the specific absorption rate value. The efficacy of magnetic hyperthermia therapy was evaluated by using the cell viability test through the following fluorescence staining: calcein acetoxymethyl ester (492/513nm), for live cells, and ethidium homodimer-1 (526/619nm) for dead cells dyes. Results: Magnetic nanoparticles when submitted to the alternating magnetic field (300 Gauss and 305kHz) produced a mean value of the specific absorption rate of 115.4±6.0W/g. The 3D culture of C6 cells evaluated by light field microscopy imaging showed the proliferation and morphology of the cells prior to the application of magnetic hyperthermia therapy. Fluorescence images showed decreased viability of cultured cells in organ-on-a-Chip by 20% and 100% after 10 and 30 minutes of the magnetic hyperthermia therapy application respectively. Conclusion: The study showed that the therapeutic process of magnetic hyperthermia in the glioblastoma on-a-chip model was effective to produce the total cell lise after 30 minutes of therapy.

RESUMO Objetivo: Avaliar a terapia de magneto-hipertermia em modelo de tumor de glioblastoma on-a-Chip. Métodos: As nanopartículas magnéticas recobertas com aminosilana foram utilizadas para a terapia da magneto-hipertermia, sendo avaliada a taxa de absorção específica das nanopartículas magnéticas em 300 Gauss e 305kHz. Uma pré-cultura de células C6 foi realizada e, seguidamente, foi feito o cultivo das células 3D no chip. O processo de magneto-hipertermia no chip foi realizado após administração de 20μL de nanopartículas magnéticas (10mgFe/mL), utilizando os parâmetros que geraram o valor da taxa de absorção específica. A eficácia da terapia de magneto-hipertermia foi avaliada pela viabilidade celular por meio dos corantes fluorescentes acetoximetiléster de calceína (492/513nm), para células vivas, e etídio homodímero-1 (526/619nm), para células mortas. Resultados: As nanopartículas magnéticas, quando submetidas ao campo magnético alternado (300 Gauss e 305kHz), produziram um valor médio da taxa de absorção específica de 115,4±6,0W/g. A cultura 3D das células C6 avaliada por imagem de microscopia de campo claro mostrou a proliferação e a morfologia das células antes da aplicação da terapia de magneto-hipertermia. As imagens de fluorescência mostraram diminuição da viabilidade das células cultivadas no organ-on-a-Chip em 20% e 100% após 10 e 30 minutos, respectivamente, da aplicação da terapia de magneto-hipertermia. Conclusão: O processo terapêutico da magneto-hipertermia no modelo de tumor glioblastoma on-a-chip foi eficaz para produzir lise total das células após 30 minutos de terapia.

Phenotype changes of oral epithelial stem cells after in vitro culture

Abstract The aim of our study was to isolate populations of keratinocyte stem cells based on the expression of cell surface markers and to investigate whether the culture could affect their phenotype. keratinocytes from human oral mucosa were sorted based on the expression of the epithelial stem cell markers p75NTR and CD71. We also examined the co-expression of other epithelial stem markers such as integrins β1 and α6 and their stem cell-like proprieties in in vitro assays. Three passages after being sorted by MACS, more than 93% of the p75NTR+ve cells lost the expression of p75NTR, while 5.46% of the p75NTR-ve gained it. Within the small population of the p75NTR+ve cells, 88% co-expressed other epithelial stem cell markers such as integrins β1 and α6, while only 28% of p75NTR-ve cells co-expressed these markers. These results were confirmed by sorting cells by FACS. Additionally, when double staining was used for sorting cells, 99% of the p75NTR+veCD71-ve and 33% of the p75NTR-veCD71+ve cells expressed both integrins, but just one week after culture, only 1.74% of the p75NTR+veCD71-ve cells still expressed p75NTR and only 0.32% still expressed CD71. Similar results were obtained when co-culturing p75NTR+ve and p75NTR-ve populations before analysis. Our results suggest that phenotype changes may be part of an intrinsic cellular mechanism to conserve levels of protein expression as they may found in the human body. In addition, in vitro culture may not offer ideal conditions for epithelial stem cell maintenance due to phenotype changes under standard culture conditions.

Estudo imuno-histoquímico e in vitro de proteínas do sistema ativador de plasminogênio em carcinomas de células escamosas de língua oral / Immunohistochemical and in vitro study of plasminogen activator system proteins in oral tongue squamous cell carcinomas

O carcinoma de células escamosas (CCE) é a neoplasia maligna mais frequente da cavidade oral e apresenta prognóstico desfavorável. Assim sendo, pesquisas têm buscado esclarecer o papel de biomarcadores no comportamento biológico do CCE oral. Nesta perspectiva, destacam-se o ativador de plasminogênio tipo uroquinase (uPA) e seu receptor (uPAR), além do inibidor do ativador de plasminogênio-1 (PAI-1). O presente trabalho analisou, por meio de imuno-histoquímica, a expressão das proteínas uPA, uPAR e PAI-1 no CCE de língua oral (CCELO) e sua relação com parâmetros clinicopatológicos. Este experimento também avaliou os efeitos in vitro da proteína recombinante humana PAI-1 (rhPAI-1) na linhagem celular SCC25, derivada de CCELO. A imunoexpressão de uPA, uPAR e PAI-1 foi analisada em 60 casos de CCELO, de forma semiquantitativa, nas células neoplásicas do front de invasão tumoral. Visando a associação dos achados imuno-histoquímicos com variáveis clinicopatológicas e taxas de sobrevida, os casos foram classificados nas categorias baixa expressão (≤50% das células positivas) e alta expressão (>50% das células positivas). No experimento in vitro, foram analisados os seguintes grupos: G0 (controle; células cultivadas na ausência de rhPAI-1), G10 (células tratadas com rhPAI-1 a 10 nM) e G20 (células tratadas com rhPAI-1 a 20 nM). Diferenças entre estes grupos foram investigadas através dos ensaios: viabilidade celular (Alamar Blue), ciclo celular (marcação com iodeto de propídio, PI), apoptose/necrose (marcação com Anexina V e PI), atividade migratória (Wound healing) e invasão celular (Transwell). A análise imuno-histoquímica revelou alta expressão do uPA na maioria dos CCELOs, mas sem relações significativas com parâmetros clinicopatológicos. As expressões do uPAR e do PAI-1, em nível membranar, foram associadas a recidivas locais (p=0,019) e ao elevado tumor budding (p=0,046), respectivamente. A expressão membranar do PAI-1 também apresentou associação significativa com o alto escore de risco histopatológico (p=0,043). A análise estatística evidenciou ausência de associações significativas entre as variáveis imunohistoquímicas (uPA, uPAR e PAI-1) e indicadores de prognóstico do CCELO (sobrevida específica e sobrevida livre da doença). No estudo in vitro, decorridas 24 horas da administração da rhPAI-1, os grupos G10 e G20 exibiram maior viabilidade celular em comparação ao grupo controle (p=0,020), assim como aumento da progressão para a fase S do ciclo celular (p=0,024). No que concerne aos percentuais de células apoptóticas e necróticas, não foram encontradas diferenças significativas entre os grupos. Nos grupos celulares cultivados na presença da rhPAI1, também foi constatado aumento da atividade migratória (p=0,039) e do potencial de invasão (p=0,039), respectivamente, nos intervalos de 24 horas e 72 horas. Os achados deste estudo sugerem o envolvimento das proteínas uPA, uPAR e PAI-1 na patogênese do CCELO. Entretanto, a expressão destes biomarcadores pode não estar relacionada com a sobrevida dos pacientes. Os resultados in vitro demonstram que o PAI-1 exerce efeitos estimulatórios na proliferação, migração e invasão celular, podendo assim contribuir para a agressividade biológica do CCELO (AU).

Squamous cell carcinoma (SCC) is the most frequent malignant neoplasm of the oral cavity and has an unfavorable prognosis. Thus, studies have sought to clarify the role of biomarkers in the biological behavior of oral SCC. Within this context, urokinase-type plasminogen activator (uPA) and its receptor (uPAR), as well as plasminogen activator inhibitor 1 (PAI-1), are particularly interesting. The present study analyzed, by means of immunohistochemistry, the expressions of uPA, uPAR and PAI-1 in oral tongue SCC (OTSCC) and their relationship with clinicopathological parameters. This experiment also evaluated the in vitro effects of recombinant human PAI-1 (rhPAI-1) on the OTSCC-derived cell line SCC-25. The immunoexpression of uPA, uPAR and PAI-1 was analyzed semiquantitatively in neoplastic cells of the invasion front of 60 OTSCC cases. Aiming to determine the association between immunohistochemical findings, clinicopathological variables and survival rates, the cases were classified as low expression (≤50% of positive cells) and high expression (>50% of positive cells). The following groups were analyzed in the in vitro experiment: G0 (control; cells cultured in the absence of rhPAI-1), G10 (cells treated with 10 nM rhPAI-1), and G20 (cells treated with 20 nM rhPAI-1). Differences between these groups were investigated using the following assays: cell viability (Alamar Blue), cell cycle (staining with propidium iodide, PI), apoptosis/necrosis (staining with Annexin V and PI), migratory activity (Wound healing), and cell invasion (Transwell). Immunohistochemical analysis revealed high expression of uPA in most OTSCC cases, but there were no significant associations with clinicopathological parameters. The high membrane expression of uPAR and PAI-1 was associated with local recurrence (p=0.019) and high tumor budding (p=0.046), respectively. Membrane expression of PAI-1 also presented a significant association with high-risk cases (p=0,043). Statistical analysis demonstrated no significant associations between the immunohistochemical variables (uPA, uPAR and PAI-1) and prognostic indicators of OTSCC (disease-specific and disease-free survival). In the in vitro experiment, 24 hours after administration of rhPAI-1, G10 and G20 exhibited greater cell viability compared to the control group (p=0.02), as well as increased progression to the S phase of the cell cycle (p=0.024). There were no significant differences in the percentages of apoptotic or necrotic cells between groups. In the groups cultured in the presence of rhPAI-1, migratory activity (p=0.039) and invasion potential (p=0.039) were found to be increased after 24 and 72 hours, respectively. The findings of this study suggest the involvement of uPA, uPAR and PAI-1 in the pathogenesis of OTSCC. Nevertheless, the expression of these biomarkers may not be related to survival of patients. The in vitro results suggest that PAI-1 exerts stimulatory effects on cell proliferation, migration and invasion and may therefore contribute to the biological aggressiveness of OTSCC (AU).

Collection and culture of human connective tissue cells from gingival explant technique for oral tissue bioengineering / Colección de células de tejido conectivo humano a partir de la técnica de explante gingival para bioingeniería de tejidos orales

SUMMARY: Cell culture is an important tool in medical, odontological and biological research laboratories, supporting cell therapies and tissue bioengineering strategies. Gingival fibroblasts present structural function, being able to modulate their metabolic capacity, which is reflected in the tissue morphology. The possibility of culturing fibroblasts in vitro, in monolayer or on three-dimensional scaffolds, for subsequent transplants in vivo opens important perspectives for the periodontal surgical clinic. The objective of the present article is to present a method of obtaining and cultivating viable human gingival fibroblasts for in vitro research. Explants derived from periodontal surgical discards were used, grown in 25 cm2 bottles to obtain a primary cell culture. After observing the proliferation and growth of the fibroblasts that interconnected and formed a monolayer network, involving the periphery of the explants, it was possible to remove the explants, to make the passage and the new subcultures were obtained in a ratio of 1:1. After 7 days, the amount of viable cells was analyzed in triplicate, using the Neubauer chamber technique, in cell culture bottles of 25 mm2 (T25) and 75 mm2 (T75). Fibroblasts were described and subclassified morphologically. The results showed a growth pattern in both bottles, but with a larger number in bottles of 75 cm2. Cells with fibroblastic morphology were subclassified into reticular and fusiform, being predominant those with fusiform morphology. In conclusion, culture of explant of human gingival connective tissue is a viable method for obtaining gingival connective tissue cells suitable for laboratory tests in cell culture, aiming at obtaining constructs for gingival tissue engineering.

RESUMEN: El cultivo celular es una herramienta importante en los laboratorios de investigación médica, odontológica y biológica, que apoyan las terapias celulares y las estrategias de bioingeniería de tejidos. Los fibroblastos gingivales presentan una función estructural, pudiendo modular su capacidad metabólica, que se refleja en la morfología tisular. La posibilidad de cultivar fibroblastos in vitro, en monocapa o en andamios tridimensionales, para trasplantes posteriores in vivo abre perspectivas importantes para la clínica de cirugía periodontal. El objetivo del presente artículo es presentar un método para obtener y cultivar fibroblastos gingivales humanos viables para investigación in vitro. Se utilizaron explantes derivados de los descartes quirúrgicos periodontales, crecidos en frascos de 25 cm2 para obtener un cultivo de células primarias. Después de observar la proliferación y el crecimiento de los fibroblastos que se interconectaron y formaron una red de monocapa, que involucraba la periferia de los explantes, fue posible eliminar los explantes, hacer el pasaje y los nuevos subcultivos se obtuvieron en una proporción de 1:1. Después de 7 días, la cantidad de células viables se analizó por triplicado, utilizando la técnica de cámara de Neubauer, en botellas de cultivo celular de 25 mm2 (T25) y 75 mm2 (T75). Los fibroblastos fueron descritos y sub-clasificados morfológicamente. Los resultados mostraron un patrón de crecimiento en ambas botellas, pero con un número mayor en botellas de 75 cm2. Las células con morfología fibroblástica se subclasificaron en reticulares y fusiformes, predominando aquellas con morfología fusiforme. En conclusión, el cultivo de explante de tejido conectivo gingival humano es un método viable para obtener células de tejido conectivo gingival adecuadas para pruebas de laboratorio en cultivos celulares, con el objetivo de obtener construcciones para la ingeniería del tejido gingival.

Amniotic membrane as a biological scaffold for dental pulp stem cell transplantation in ocular surface reconstruction / Membrana amniótica como substrato biológico para o transplante de células-tronco da polpa do dente de leite na reconstrução da superfície ocular

ABSTRACT Purpose: To evaluate the ability of human immature dental pulp stem cells, which are mesenchymal stem cells of neural crest origin, to differentiate into the corneal epithelium for purposes of corneal transplantation and tissue engineering when cultured on de-epithelized amniotic membranes. Methods: We compared the immunophenotypes (ABCG2, K3/12, and vimentin) of cells grown on amniotic membranes or plastic surfaces under serum-free conditions or in culture media containing serum or serum replacement components. Results: Immature dental pulp stem cells grown on amniotic membranes under basal conditions are able to maintain their undifferentiated state. Our data also suggest that the culture medium used in the present work can modulate the expression of immature dental pulp stem cell markers, thus inducing epithelial differentiation of these cells in vitro. Conclusions: Our results suggest that the amniotic membrane is a good choice for the growth and transplantation of mesenchymal stem cells, particularly immature dental pulp stem cells, in clinical ocular surface reconstruction.

RESUMO Objetivos: Avaliar a capacidade das células-tronco imaturas da polpa do dente de leite que são células-tronco mesenquimais de origem da crista neural, de se diferenciarem no epitélio corneano para fins de transplante de córnea e engenharia de tecidos quando cultivadas em membrana amnióticas desepitelizadas. Métodos: Foram comparamos so imunofenótipo (ABCG2, CK3/12 e vimentina) de células cultivadas em membranas amnióticas ou em superfícies plásticas sob condições livres de soro ou em meios de cultura contendo soro ou componentes de substituição de soro. Resultados: Células-tronco imaturas da polpa do dente de leite cultivadas sobre membrana amniótica em condições basais são capazes de manter seu estado indiferenciado. Nossos dados também sugerem que o meio de cultura utilizado no presente trabalho pode modular a expressão de marcadores de células-tronco imaturas da polpa do dente de leite, induzindo a diferenciação epitelial destas células in vitro. Conclusão: Nossos resultados sugerem que a membrana amniótica é uma boa escolha para o crescimento e transplante de células-tronco mesenquimais, particularmente as células-tronco imaturas da polpa do dente de leite, na reconstrução da superfície ocular.

Isolation and characterization of a human cementocyte-like cell line, HCY-23

Abstract Cementum is the mineralized tissue covering the tooth root that functions in tooth attachment and post-eruptive adjustment of tooth position. It has been reported to be highly similar to bone in several respects but remains poorly understood in terms of development and regeneration. Here, we investigate whether cementocytes, the residing cells in cellular cementum, have the potential to be protagonist in cementum homeostasis, responding to endocrine signals and directing local cementum metabolism. Cells from healthy erupted human teeth were isolated using sequential collagenase/EDTA digestions, and maintained in standard cell culture conditions. A cementocyte-like cell line was cloned (HCY-23, for human cementocyte clone 23), which presented a cementocyte compatible gene expression signature, including the expression of dentin matrix protein 1 ( DMP1 ), sclerostin ( SOST ), and E11/gp38/podoplanin ( E11 ). In contrast, these cells did not express the odontoblast/dentin marker dentin sialoprotein ( DSPP ). HCY-23 cells produced mineral-like nodules in vitro under differentiation conditions, and were highly responsive to inorganic phosphate (Pi). Within the limits of the present study, it can be concluded that cementocytes are phosphate-responsive cells, and have the potential do play a key role in periodontal homeostasis and regeneration.

Morphological observation of bone marrow mesenchymal stem cells under matrigel three dimensional culture conditions / Observación morfológica de células madre mesenquimales de médula ósea en condiciones de cultivo tridimensional con matrigel

SUMMARY: Matrigel is a basement membrane matrix extracted from the EHS mouse tumor containing extracellular matrix protein, its main components are laminin, type IV collagen, nestin, heparin sulfate, growth factor and matrix metalloproteinase.At room temperature, Matrigel polymerized to form a three dimensional matrix with biological activity. It can simulate the structure, composition, physical properties and functions of the cell basement membrane in vivo, which is beneficial to the culture and differentiation of the cells in vitro, and can be used for the study of cell morphology, biochemical function, migration, infection and gene expression. In this study, Matrigel three-dimensional culture model of bone marrow mesenchymal stem cells(BMSCs) was established, and its morphology, proliferation and survival were observed. BMSCs were isolated and cultured with whole bone marrow adherence method. The Second generation BMSCs with good growth condition were selected and mixed with Matrigel to form cell gel complexes. The morphology and proliferation of mesenchymal stem cells were observed by phase contrast microscope and HE staining,Live/Dead staining was used to evaluate the cell activity.Phase contrast microscopy showed that BMSCs were reticulated in Matrigel and proliferated well, After 7 days, the matrix gel gradually became soft and collapsed, a few cell reticular crosslinking growth was seen at 14 days; HE staining showed that the cytoplasm of the cells was larger on the fourth day and the cells were elongated and cross-linked on the seventh day; Live/dead staining showed that most cells showed green fluorescence with the prolongation of culture time, on the first, 4 and 7 days, the activity of bone marrow mesenchymal stem cells in Matrigel gradually increased, and the percentages were 92.57 %, 95.54 % and 97.37 %, respectively. Matrigel three-dimensional culture system can maintain the morphology, function and proliferation ability of bone marrow mesenchymal stem cells.

RESUMEN: Matrigel es una matriz de membrana basal extraída del tumor de ratón EHS que contiene proteína de matriz extracelular. Los componentes principales son laminina, el colágeno tipo IV, nestina, sulfato de heparina, factor de crecimiento y metaloproteinasa de matriz. A temperatura ambiente, Matrigel se polimerizó para formar una matriz tridimensional. Es posible simular la estructura, la composición, las propiedades físicas y las funciones de la membrana basal celular in vivo, lo que es beneficioso para el cultivo y la diferenciación de las células in vitro, y se puede utilizar para el estudio de la morfología celular, la función bioquímica, la migración, infección y expresión génica. En este estudio, se estableció el modelo de cultivo tridimensional Matrigel de células madre mesenquimales de médula ósea (BMSC), y se observó su morfología, proliferación y supervivencia. Las BMSC fueron aisladas y cultivadas con el método de adherencia de la médula ósea completa. Se seleccionaron las BMSC de segunda generación con buenas condiciones de crecimiento y se mezclaron con Matrigel para formar complejos de gel de células. La morfología y la proliferación de las células madre mesenquimales se observaron con microscopio de contraste de fase y se tiñó con Hematoxilina-Eosina (HE); para evaluar la actividad celular se usó la tinción Live/Dead. La microscopía de contraste mostró que las BMSC se reticularon en Matrigel y proliferaron bien. Después de 7 días, se observó que el gel de matriz gradualmente se volvió blando y colapsó, y se visualizó un cruce transversal de algunas células reticulares a los 14 días. La tinción mostró que la mayoría de las células mostraron una fluorescencia verde con la prolongación del tiempo de cultivo; en los primeros 4 y 7 días, la actividad de las células madre mesenquimales de la médula ósea en Matrigel aumentó gradualmente y los porcentajes fueron de 92,57 %, 95,54 % y 97,37 %, respectivamente. El sistema de cultivo tridimensional de Matrigel puede mantener la morfología, la función y la capacidad de proliferación de las células madre mesenquimales de la médula ósea.

Induction of pluripotent stem cells by reprogramming human ocular fibroblasts under xeno-free conditions / Indução de células-tronco pluripotentes pela reprogramação de fibroblastos oculares humanos sob condições xeno-livre

ABSTRACT Purposes: To develop an efficient and xeno-free standard eye-derived induced pluripotent stem cell reprogramming protocol for use during induced pluripotent stem cell-based cell therapies in treating retinal degenerative diseases and to compare the relative effectiveness of both animal- and non-animal-derived culture systems in the generation of induced pluripotent stem cells. Methods: Primary cultured human pterygium fibroblasts and human Tenon's capsule fibroblasts were induced to induced pluripotent stem cells using a non-in­tegrated virus under two xeno-free systems; as part of this study, a traditional non-xeno-free reprogramming system was also assessed. Induced pluripotent stem cell clones were selected and counted by live staining. Reprogramming efficiencies were evaluated between the fibroblasts and among different culture systems. In a series of experiments, such as PCR and immunofluorescence staining, the induced pluripotent stem cells were characterized. Results: Human pterygium fibroblast- and human Tenon's capsule fibroblast-derived induced pluripotent stem cells were successfully established using different reprogramming systems, under which they exhibited properties of induced pluripotent stem cells. Reprogramming efficiencies of induced pluripotent stem cells using the cell therapy system, the traditional system, and the E6/E8 system were 0.014%, 0.028%, and 0.001%, respectively, and those of human pterygium fibroblast- and human Tenon's capsule fibroblast-derived induced pluripotent stem cells-using the aforementioned systems-were 0.018% and 0.017%, respectively. Conclusions: Sendai virus facilitates induced pluripotent stem cell reprogramming of ocular fibroblasts-both human pterygium and human Tenon's capsule fibroblasts being safe and efficient for induced pluripotent stem cell reprogramming. Although the reprogramming efficiencies of ocular-derived induced pluripotent stem cells under xeno-free conditions were not superior to those observed using the traditional reprogramming system, the cell therapy system reprogramming system is a good option when induced pluripotent stem cells are to be induced under xeno-free conditions.

RESUMO Objetivos: Desenvolver um protocolo padrão, eficiente e xeno-livre, para a reprogramação de células-tronco pluripotentes induzidas, que possa ser usado durante as terapias de células-tronco pluripotentes induzidas para o tratamento de doenças degenerativas da retina, e comparar a eficácia relativa de sistemas de cultivo de origem animal e de origem não animal na geração de células-tronco pluripotentes induzidas. Métodos: Cultivos primários de fibroblastos de pterígio humano e de fibroblastos da cápsula de Tenon humanos foram induzidos a células-tronco pluripotentes induzidas usando um vírus não integrado sob dois sistemas xeno-livres; um sistema tradicional de reprogramação não xeno-livre também foi avaliado como parte deste estudo. Os clones de células-tronco pluripotentes induzidas foram selecionados e contados por coloração de células vivas. As eficiências de reprogramação foram avaliadas entre os diferentes fibroblastos e entre os diferentes sistemas de cultivo. Uma série de experimentos, como o PCR e a coloração por imunofluorescência, foram conduzidos para caracterizar as células-tronco pluripotentes induzidas. Resultados: Célu­las-tronco pluripotentes induzidas derivadas de fibroblastos de pterígio humano e fibroblastos da cápsula de Tenon humanos foram estabelecidas com sucesso sob diferentes sistemas de reprogramação e exibiram propriedades de células-tronco pluripotentes induzidas. As eficiências de reprogramação das células-tronco pluripotentes induzidas usando o sistema de terapia celular, o sistema tradicional e o sistema E6/E8 foram 0,014, 0,028% e 0,001%, respectivamente. Além disso, as efi­ciências de reprogramação de células-tronco pluripotentes induzidas derivadas de fibroblastos de pterígio humano e de fibroblastos da cápsula de Tenon humanos usando todos os sistemas acima foram de 0,018% e 0,017%, respectivamente. Conclusões: O vírus Sendai pode ser usado para facilitar a reprogramação de fibroblastos oculares pelas células-tronco pluripotentes induzidas. Tanto os fibroblastos de pterígio humano quanto os fibroblastos da cápsula de Tenon humanos são seguros e eficientes para a reprogramação de células-tronco pluripotentes induzidas. Embora as eficiências de reprogramação das células-tronco pluripotentes induzidas de origem ocular sob condições xeno-livres não tenham sido superiores às eficiências observadas para o sistema tradicional de reprogramação, o sistema de reprogramação sistema de terapia celular é uma boa opção para a indução de células-tronco pluripotentes induzidas sob condições xeno-livres.

Characteristics of human natal stem cells cultured in allogeneic medium

Abstract Recently, human natal dental pulp stem cells (hNDP-SCs) have been characterized in vitro and it has been shown that they satisfy criteria defining human mesenchymal stromal cells (MSCs), as proposed by the International Society for Cellular Therapy. However, these results were reached in the presence of xenogeneic expansion medium, which has the potential to alter the cells' functional capacity. To determine the validity of the previously reported hNDP-SCs characteristics for human cell therapy, we have cultured hNDP-SCs in allogeneic expansion medium. Two hNDP-SC lineages were isolated from vital natal teeth, donated by a healthy newborn female and cultured in 2% platelet rich plasma (PRP). Analysis of the phenotypic expressions, proliferation rates, viability, telomerase length and in vitro adipogenic, osteogenic and chondrogenic differentiation potentials of two hNDP-SCs lineages (Zn001 and Zn002) were performed. Both lineages displayed similar morphology, proliferation rates, adipogenic, chondrogenic and osteogenic differentiation potential. Telomere shortening by 41.0% and 13.49% occurred from 3rd till 14th passage for lineages Zn001 and Zn002 respectively. Viability of both lineages was higher than 90%. Flow cytometry demonstrated that both lineages were positive to the majority of tested markers, including markers, which were negatively, expressed when hNDP-SCs were cultured previously in xenogeneic medium. Using immune-cytochemistry the cells were shown to express beta III-tubulin, nestin, neurofilaments and Nanog. PRP used as allogeneic medium is suitable for cultivation of hNDP-SCs.

Resumo Recentemente, células-tronco da polpa dental humana (hNDP-SCs) foram caracterizadas in vitro e foi demonstrado que elas satisfazem critérios que definem células mesenquimais do estroma humana (MSCs), tal como proposto pela Sociedade Internacional para Terapia Celular. No entanto, esses resultados foram alcançados na presença de meio de expansão xenogênico, que tem o potencial de alterar a capacidade funcional das células. Para determinar a validade das características das hNDP-SCs anteriormente relatadas para a terapia celular humana, cultivamos hNDP-SCs em meio de expansão alogênico. Duas linhagens hNDP-SC foram isoladas de dentes natais vitais, doadas por uma recém-nascida saudável, e cultivadas em plasma rico em plaquetas a 2% (PRP). Análises das expressões fenotípicas, taxas de proliferação, viabilidade, comprimento de telomerase e potenciais de diferenciação adipogênica, osteogênica e condrogênica in vitro das duas linhagens hNDP-SC (Zn001 e Zn002) foram realizadas. Ambas as linhagens apresentaram morfologia, taxas de proliferação, potencial de diferenciação adipogênico, condrogênico e osteogênico semelhantes. O encurtamento dos telômeros em 41,0% e 13,49% ocorreu da 3ª até a 14ª passagem para as linhagens Zn001 e Zn002, respectivamente. A viabilidade de ambas as linhagens foi superior a 90%. A citometria de fluxo demonstrou que ambas as linhagens foram positivas para a maioria dos marcadores testados, incluindo marcadores, que foram negativamente expressados quando hNDP-SCs foram previamente cultivadas em meio xenogênico. Usando análise imunocitoquímica, as células mostraram expressar a beta III-tubulina, nestina, neurofilamentos e Nanog. O PRP usado como meio alogênico mostrou-se adequado para o cultivo de hNDP-SCs.

New methodologies for old problems: tridimensional gastrointestinal organoids and guts-on-a-chip / Novas metodologias para velhos problemas: organoides gastrointestinais e guts-on-a-chip tridimensionais

ABSTRACT Objectives: The present review intended to present a critical overview of the methodological and experimental advances concerning tridimensional cell culture models within the scope of gastrointestinal research. Methods: A literature review was performed and some of the main published articles in the area were mentioned. Main results: Classic studies and high impact results were presented, starting from the pioneer works with gastrointestinal organoids, with a small gut organoid, to the achievement of guts-on-a-chip and multi-organ-chips. It was also discussed which implications the construction of such co-cultures bring, as well as future applications arising from these new methodologies. Conclusions: Despite the still discrete number of publications, in quantitative terms, there are qualitative promising and consistent results addressing physiopathological aspects and new therapeutic perspectives of tridimensional in vitro cultures in the gastroenterology field. It is expected, thus, that such new methodological approaches, including organoids and guts-on-a-chip, may contribute decisively to the advance in knowledge on basic aspects, as well as on the translation to new therapeutic approaches in gastrointestinal diseases.

RESUMO Objetivos: A presente revisão visou apresentar uma abordagem crítica dos avanços metodológicos e experimentais referentes a modelos de cultura celular tridimensionais no âmbito do sistema gastrintestinal. Métodos: Foi realizada revisão da literatura com ênfase nos principais artigos publicados na área. Resultados principais: São apresentados trabalhos clássicos e resultados de maior impacto, desde os trabalhos pioneiros com organoides do sistema gastrintestinal, com intestino delgado, até a obtenção de guts-on-a-chip e multi-organ-chips. Discutiu-se, ainda, as implicações decorrentes da elaboração de tais co-culturas, bem como as futuras aplicações decorrentes dessas novas metodologias. Conclusões: Apesar do número ainda discreto de publicações, em termos quantitativos, há, qualitativamente, resultados promissores e consistentes abordando aspectos fisiopatológicos e de novas perspectivas terapêuticas em gastrenterologia decorrentes das culturas tridimensionais in vitro. É esperado, portanto, que essas novas abordagens metodológicas incluindo organoides e guts-on-a-chip possam contribuir decisivamente para o avanço no conhecimento sobre de aspectos básicos, bem como para a translação do conhecimento para novas abordagens terapêuticas em doenças gastrintestinais.

Comparative analysis of Mouse Inoculation Test and Virus Isolation in Cell Culture for rabies diagnosis in animals of Parana, Brazil

Abstract INTRODUCTION: Rabies is an acute zoonotic disease, caused by a rhabdovirus that can affect all mammals, and is commonly transmitted by the bite of a rabid animal. The definitive diagnosis is laboratorial, by the Fluorescent Antibody Test (FAT) as a quick test and Mouse Inoculation Test (MIT) as a confirmatory test (gold standard). Studies conducted over the past three decades indicate that MIT and Virus Isolation in Cell Culture (VICC) can provide the same effectiveness, the latter being considered superior in bioethics and animal welfare. The aim of this study was to compare VICC with MIT, in terms of accuracy, biosafety and occupational health, supply and equipment costs, bioethics and animal welfare, in a Brazilian public health lab. METHODS: We utilized 400 samples of animal neurological tissue to compare the performance of VICC against MIT. The variables analyzed were accuracy, biosafety and occupational health, time spent in performing the tests, supply and equipment costs, bioethics and animal welfare evaluation. RESULTS: Both VICC and MIT had almost the same accuracy (99.8%), although VICC presented fewer risks regarding biosafety and mental health of the technicians, and reduced time between inoculation and obtaining the results (approximately 22 days less). In addition, VICC presented lower supply costs (86.5% less), equipment costs (32.6% less), and the advantage of not using animals. CONCLUSIONS: These results confirm that VICC can replace MIT, offering the same accuracy and better features regarding cost, results, biosafety and occupational health, and bioethics and animal welfare.

Characterization of air-liquid interface culture of A549 alveolar epithelial cells

Alveolar epithelia play an essential role in maintaining the integrity and homeostasis of lungs, in which alveolar epithelial type II cells (AECII) are a cell type with stem cell potential for epithelial injury repair and regeneration. However, mechanisms behind the physiological and pathological roles of alveolar epithelia in human lungs remain largely unknown, partially owing to the difficulty of isolation and culture of primary human AECII cells. In the present study, we aimed to characterize alveolar epithelia generated from A549 lung adenocarcinoma cells that were cultured in an air-liquid interface (ALI) state. Morphological analysis demonstrated that A549 cells could reconstitute epithelial layers in ALI cultures as evaluated by histochemistry staining and electronic microscopy. Immunofluorescent staining further revealed an expression of alveolar epithelial type I cell (AECI) markers aquaporin-5 protein (AQP-5), and AECII cell marker surfactant protein C (SPC) in subpopulations of ALI cultured cells. Importantly, molecular analysis further revealed the expression of AQP-5, SPC, thyroid transcription factor-1, zonula occludens-1 and Mucin 5B in A549 ALI cultures as determined by both immunoblotting and quantitative RT-PCR assay. These results suggest that the ALI culture of A549 cells can partially mimic the property of alveolar epithelia, which may be a feasible and alternative model for investigating roles and mechanisms of alveolar epithelia in vitro.

Micromass cultures are effective for differentiation of human amniotic fluid stem cells into chondrocytes

OBJECTIVES: Articular cartilage is vulnerable to injuries and undergoes an irreversible degenerative process. The use of amniotic fluid mesenchymal stromal stem cells for the reconstruction of articular cartilage is a promising therapeutic alternative. The aim of this study was to investigate the chondrogenic potential of amniotic fluid mesenchymal stromal stem cells from human amniotic fluid from second trimester pregnant women in a micromass system (high-density cell culture) with TGF-β3 for 21 days. METHODS: Micromass was performed using amniotic fluid mesenchymal stromal stem cells previously cultured in a monolayer. Chondrocytes from adult human normal cartilage were used as controls. After 21 days, chondrogenic potential was determined by measuring the expression of genes, such as SOX-9, type II collagen and aggrecan, in newly differentiated cells by real-time PCR (qRT-PCR). The production of type II collagen protein was observed by western blotting. Immunohistochemistry analysis was also performed to detect collagen type II and aggrecan. This study was approved by the local ethics committee. RESULTS: SOX-9, aggrecan and type II collagen were expressed in newly differentiated chondrocytes. The expression of SOX-9 was significantly higher in newly differentiated chondrocytes than in adult cartilage. Collagen type II protein was also detected. CONCLUSION: We demonstrate that stem cells from human amniotic fluid are a suitable source for chondrogenesis when cultured in a micromass system. amniotic fluid mesenchymal stromal stem cells are an extremely viable source for clinical applications, and our results suggest the possibility of using human amniotic fluid as a source of mesenchymal stem cells.

Cardiac tissue engineering: current state-of-the-art materials, cells and tissue formation / Engenharia de tecidos cardíacos: atual estado da arte a respeito de materiais, células e formação tecidual

ABSTRACT Cardiovascular diseases are the major cause of death worldwide. The heart has limited capacity of regeneration, therefore, transplantation is the only solution in some cases despite presenting many disadvantages. Tissue engineering has been considered the ideal strategy for regenerative medicine in cardiology. It is an interdisciplinary field combining many techniques that aim to maintain, regenerate or replace a tissue or organ. The main approach of cardiac tissue engineering is to create cardiac grafts, either whole heart substitutes or tissues that can be efficiently implanted in the organism, regenerating the tissue and giving rise to a fully functional heart, without causing side effects, such as immunogenicity. In this review, we systematically present and compare the techniques that have drawn the most attention in this field and that generally have focused on four important issues: the scaffold material selection, the scaffold material production, cellular selection and in vitro cell culture. Many studies used several techniques that are herein presented, including biopolymers, decellularization and bioreactors, and made significant advances, either seeking a graft or an entire bioartificial heart. However, much work remains to better understand and improve existing techniques, to develop robust, efficient and efficacious methods.

RESUMO Doenças cardiovasculares são responsáveis pelo maior número de mortes no mundo. O coração possui capacidade de regeneração limitada, e o transplante, por consequência, representa a única solução em alguns casos, apresentando várias desvantagens. A engenharia de tecidos tem sido considerada a estratégia ideal para a medicina cardíaca regenerativa. Trata-se de uma área interdisciplinar, que combina muitas técnicas as quais buscam manter, regenerar ou substituir um tecido ou órgão. A abordagem principal da engenharia de tecidos cardíacos é criar enxertos cardíacos, sejam substitutos do coração inteiro ou de tecidos que podem ser implantados de forma eficiente no organismo, regenerando o tecido e dando origem a um coração completamente funcional, sem desencadear efeitos colaterais, como imunogenicidade. Nesta revisão, apresentase e compara-se sistematicamente as técnicas que ganharam mais atenção nesta área e que geralmente focam em quatro assuntos importantes: seleção do material a ser utilizado como enxerto, produção do material, seleção das células e cultura de células in vitro. Muitos estudos, fazendo uso de várias das técnicas aqui apresentadas, incluindo biopolímeros, descelularização e biorreatores, têm apresentado avanços significativos, seja para obter um enxerto ou um coração bioartifical inteiro. No entanto, ainda resta um grande esforço para entender e melhorar as técnicas existentes, para desenvolver métodos robustos, eficientes e eficazes.