Liver transplantation is the only definitive treatment for many diseases that affect this organ, however, its quantity and viability are reduced. The study of liver scaffolds based on an extracellular matrix is a tissue bioengineering strategy with great application in regenerative medicine. Collectively, recent studies suggest that liver scaffold transplantation may assist in reestablishing hepatic function in preclinical diseased animals, which represents a great potential for application as a treatment for patients with liver disease in the future. This review focuses on useful strategies to promote liver scaffold transplantation and the main open questions about this context. We outline the current knowledge about ex vivo bioengineered liver transplantation, including the surgical techniques, recipient survival time, scaffold preparation before transplantation, and liver disease models. We also highlight the current limitations and future directions regarding in vivo bioengineering techniques.
Com o objetivo de se determinar o número de colmeias por hectare para polinização de maçã, foram levadas a um pomar uma a uma, a cada dois dias, 5 colônias de abelhas africanizadas, marcadas com fósforo radioativo (32P). Cada colmeia continha uma população estimada em cerca de 35.000 abelhas. Na área experimental de aproximadamente 0,8 ha, foram demarcadas macieiras a cada 10 m a partir do centro onde estavam as colmeias, formando quatro alas perpendiculares em formato de cruz, até a uma distância de 50m. As abelhas foram coletadas com puçá quando visitavam as flores, durante 10 minutos por dia em cada árvore estaqueada e por 10 dias consecutivos. Pôde-se observar que o número de abelhas marcadas coletadas foi aumentando à medida que se acrescentavam mais colmeias no pomar, sendo que não houve diferença estatística significativa entre o número médio de abelhas coletadas nas flores com 2, 3, 4 e 5 colmeias, concluindo-se então que 2,5 colmeias por ha seriam suficientes para visitar todas as flores do pomar.
Acellular liver scaffolds (ALS) produced by decellularization have been successfully explored for distinct regenerative purposes. To date, it is unknown whether transplanted ALSs are affected by cirrhotic livers, either becoming cirrhotic themselves or instead remaining as a robust template for healthy cell growth after transplantation into cirrhotic rats. Moreover, little is known about the clinical course of recipient cirrhotic livers after ALS transplantation. To address these questions, we transplanted ALSs into cirrhotic rats previously treated with the granulocyte colony-stimulating factor. Here, we report successful cellular engraftment within the transplanted ALSs at 7, 15, and 30 days after transplantation. Recellularization was orchestrated by liver tissue cell activation, resident hepatocytes and bile duct proliferation, and an immune response mediated by the granulocyte components. Furthermore, we showed that transplanted ALSs ensured a pro-regenerative and anti-inflammatory microenvironment, attracted vessels from the host cirrhotic tissue, and promoted progenitor cell recruitment. ALS transplantation induced cirrhotic liver regeneration and extracellular matrix remodeling. Moreover, the transplanted ALS sustained blood circulation and attenuated alterations in the ultrasonographic and biochemical parameters in cirrhotic rats. Taken together, our results confirm that transplanted ALSs are not affected by cirrhotic livers and remain a robust template for healthy cell growth and stimulated cirrhotic liver regeneration.
Aims: The aim of this work was to evaluate the optimal radiation dose to maintain the antioxidant capacity of conventional and organic acaí freeze-dried pulps.
Study Design: All analyses were conducted in sextuplicate for each experiment.
Place and Duration of Study: Were conducted at the LATAIA and the irradiation processes at the Laboratory of Nuclear Instrumentation, UFRJ, Rio de Janeiro, Brazil. The study was carried out from July, 2018 to March, 2020.
Methodology: Frozen acaí pulps from two commercial brands, one of them organic and other conventional were used and purchased in the city of Rio de Janeiro, packed in plastic bags containing 1 kg. For each brand, frozen pulps (5 kg) were thawed at 4ºC, opened and homogenized. Samples were subdivided into aliquots ranging from 20 to 300 g for the assays and frozen inside the plastic bags until analyses. A Cobalt 60, Gammacell irradiator was used and doses of 1.25. 2.5. 3.75 and 5 kGy were applied in the in natura pulps. Antioxidant capacity was performed by the ORAC and DPPH methods and, phenolic compounds by Folin Ciocalteau method and, total anthocyanins and majority anthocyanidins by HPLC.
Results: Anthocyanins increases at irradiaton dose up to 3.75 kGy in organic açaí but it was not significant in conventional acaí irradiated at low doses (1.25 to 3.75 kGy). Our results suggested that irradiation doses up to 5 kGy do not decrease total phenolic or anthocyanin contents nor the pulp antioxidant activity compared with non-irradiated pulps. The results showed irradiation did not reduce these analytes, and even increased in the organic acaí.
Conclusion: The study evidenced that gamma irradiation can be an alternative safe process for fruit pulps preservation. We conclude that irradiation doses up to 5 kGy can be used in acaí without harming its antioxidant properties.
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