Abstract
Tras su administración sistémica,los adenovirus recombinantes se concentran en el hígado, lo que les validaría para la transferencia génica a este órgano, pero existen efectos colaterales. En este trabajo se ha analizado el impacto de la infección sobre la cantidad y composición de las lipoproteínas de muy baja densidad (VLDL) secretadas en hepatocitos de rata en cultivo.Se generaron 2 vectores adenovirales, con ADNc en dirección sentido o antisentido, ambos con capacidad infectiva pero no de propagación. Se infectaron cultivos de hepatocitos de rata con una dosis no citotóxica y se analizaron las VLDL secretadas durante los 3 períodos de 24 h posteriores a la infección y el contenido en lípidos del citosol.La infección causó un moderado descenso en la secreción de apo B48 y de éster de colesterol durante las primeras 24 h, pero posteriormente se redujo drásticamente la secreción de partículas con apo B48 y apo B100 y su contenido en lípidos. Además, modificó sus proporciones, aumentando el porcentaje de colesterol libre a costa del esterificado, que llegó a ser indetectable. La menor secreción de VLDL no conllevó una acumulación de lípido intracelular e, incluso, descendió la masa citosólica de éster de colesterol.La infección con adenovirus reduce la secreción hepatocitaria de VLDL y su porcentaje de colesterol esterificado y, a diferencia de otros virus, estas acciones no parecen ir acompañadas de esteatosis hepatocelular.After systemic administration, recombinant adenoviruses are rapidly concentrated in the liver, making them good candidates for gene transfer to this organ. However, there are collateral effects. In this study, we analyzed the effect of adenoviral infection on the number and composition of very low-density lipoproteins (VLDL) secreted by cultured rat hepatocytes.Two recombinant adenoviruses were developed, each containing cDNA in sense or antisense orientation, and with infective but not propagating ability. Cultured rat hepatocytes were infected with a subcytotoxic adenoviral dose. Secretion of VLDL particles during 3 consecutive 24 h-periods after infection and cytosolic lipid content were characterized.During the first 24 h period, apo B48 and cholesteryl ester secretion moderately decreased. However, in longer incubations, infection dramatically reduced both apo B48 and apo B100 secretion, as well as VLDL lipid content. Lipid proportion was also modified: free cholesterol increased while cholesteryl ester decreased to undetectable levels. Decreased VLDL secretion was not associated with intracellular lipid accumulation; indeed, cholesteryl ester mass was even lower than in noninfected cells.Adenovirus infection causes hepatocytes to secrete less VLDL and to reduce their cholesteryl ester percentage. In contrast with the effects of other viruses, these effects are not accompanied by hepatocellular steatosis.
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