A major roadblock to successful organ bioengineering is the need for a functional vascular network within the engineered tissue. Here, we describe the fabrication of three‐dimensional, naturally derived scaffolds with an intact vascular tree. Livers from different species were perfused with detergent to selectively remove the cellular components of the tissue while preserving the extracellular matrix components and the intact vascular network. The decellularized vascular network was able to withstand fluid flow that entered through a central inlet vessel, branched into an extensive capillary bed, and coalesced into a single outlet vessel. The vascular network was used to reseed the scaffolds with human fetal liver and endothelial cells. These cells engrafted in their putative native locations within the decellularized organ and displayed typical endothelial, hepatic, and biliary epithelial markers, thus creating a liver‐like tissue in vitro. Conclusion: These results represent a significant advancement in the bioengineering of whole organs. This technology may provide the necessary tools to produce the first fully functional bioengineered livers for organ transplantation and drug discovery. (HEPATOLOGY 2011;53:604‐617)

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Objetivo. Evaluar y reportar las características clínicas y los resultados de la infección por SARS-CoV-2 en mujeres embarazadas y recién nacidos en América Latina. Métodos. Estudio descriptivo basado en el reporte prospectivo de las unidades constituyentes de la Red de la Sociedad Iberoamericana de Neonatología. Resultados. De 86 mujeres embarazadas con COVID-19 confirmadas por RT-PCR en siete países (6 de América Latina y Guinea Ecuatorial) 68% (59) fueron asintomáticas. Del 32% de mujeres sintomáticas, 89% (24) tuvieron síntomas leves y 3,5% (3) presentaron síntomas respiratorios graves. Ninguna mujer falleció. La tasa de cesáreas fue de 38%; la edad gestacional fue < 37 semanas en 6% de los casos. Se realizó RT-PCR a todos los recién nacidos (RN) entre las 16 y 36 horas de vida; en 6 (7%) el resultado del hisopado fue positivo. Todos ellos presentaron dificultad respiratoria leve y transitoria; ninguno falleció. Dos RN con RT-PCR negativa fallecieron por otras causas. Se autorizó el amamantamiento en solo 24% de las madres; en 13% se extrajo leche y en 63% se alimentó al RN con fórmula. En 76% de los casos se separó al binomio madre-hijo, y en 95% de los casos la madre no pudo ser acompañada en el parto ni el puerperio. Conclusiones. Son preocupantes la falta de acompañamiento materno, la baja tasa de lactancia y la frecuente separación de la díada madre-hijo. El equipo de salud debe reflexionar sobre la necesidad de defender el cuidado humanizado y centrado en la familia durante esta pandemia.

Limitations of synthetic biomaterials for abdominal wall repair have led investigators to seek naturally derived matrices, such as human acellular dermis, because of their excellent biocompatibility and their ability to naturally interface with host tissues with minimal tissue response. In this study, we investigated two different biomaterials derived from human dermis (FlexHD acellular dermis and FlexHD acellular dermis-thick) in a rabbit abdominal hernia repair model. One quarter of the abdominal wall was replaced with each biomaterial, and the animals were followed for up to 24 weeks. Rabbit hernias repaired with AlloDerm, a commercially available acellular dermal matrix, and sham operated animals served as controls. Retrieved samples of these implants were assessed grossly and histologically. Collagen production measurements and tension studies were performed. FlexHD acellular dermis, FlexHD acellular dermis-thick, and AlloDerm maintained their strength in the rabbit hernia repair model with no incidence of hernia formation or bowel adhesion. The exact size measurements at 24 weeks were 217.0 +/- 20.9% for FlexHD acellular dermis, 200.8 +/- 23.5% for FlexHD acellular dermis-thick, and 209.7 +/- 32.9% for AlloDerm. Macroscopic and microscopic evaluation showed excellent integration and tissue formation. All biomaterials studied harbored cells that produced new collagen fibers, and a six-fold increase in these fibers was observed at 24 weeks. This study shows that acellular biomaterials derived from human dermis are suitable for abdominal hernia repair.

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