ABSTRACT
El trasplante hepático (TH) es el único tratamiento efectivo existente para las enfermedades hepáticas en fase terminal. La desproporción entre demanda y oferta de órganos constituye su principal limitación, planteando la necesidad de buscar alternativas de tratamiento. El trasplante de hepatocitos humanos o trasplante celular hepático (TCH) constituye, en el momento actual, la mejor opción terapéutica puente al restablecimiento de la función hepática o al trasplante hepático. Consiste en trasplantar hepatocitos humanos totalmente diferenciados a un órgano receptor, en cantidad suficiente para que estos sobrevivan y restauren la función hepática normal, basándose en la capacidad de regeneración hepática. El TCH consta básicamente de 4 pasos: el aislamiento de los hepatocitos a partir de injertos hepáticos descartados para TH, la preparación de las suspensiones celulares, la criopreservación de los hepatocitos aislados y, finalmente, su implante en el receptor. Esta terapia se ha llevado a cabo en pacientes con insuficiencia hepática aguda de distintas etiologías con intención de sustituir o servir de puente al TH y en el tratamiento de pacientes pediátricos con errores congénitos del metabolismo con objetivo de reemplazar el déficit enzimático causante de la enfermedad. En el Hospital La Fe de Valencia hemos puesto en marcha una Unidad de Terapia Celular Hepática y llevado a cabo el primer TCH en España, abriendo una nueva línea de trabajo dentro del Programa de Trasplante Hepático (AU)
Liver transplantation has been remarkably effective in the treatment of patients with end-stage liver disease. However, disparity between solid-organ supply and increased demand is the main limitation, resulting in longer waiting times and an increase in the mortality of transplant recipients. This situation creates the need to seek alternatives to orthotopic liver transplantation. Hepatocyte transplantation or liver cell transplantation has been proposed as the best method to support patients, a bridge to restore liver function or liver transplant. The procedure consists in transplanting individual cells in a recipient organ in enough quantity to survive and restore the function. The capacity of hepatic regeneration constitutes the biological basis of hepatocyte transplantation. Liver cell transplantation is carried out by means of the isolation of hepatocytes from donor liver rejected for orthotopic transplantation, to prepare a cell suspension for infusion, cryopreservation and, finally, hepatocytes are implanted into the recipient. This may be an optional therapeutic procedure in some patients with inborn errors of metabolism, fulminant hepatic failure, and acute and chronic liver failure, as a bridge to orthotopic liver transplantation. The first hepatocyte transplantation in Spain was performed in the Cell Therapy Unit of the Hospital La Fe of Valencia, creating a new research line in the transplant program (AU)
Subject(s)
Humans , Male , Female , Child , Metabolism, Inborn Errors/drug therapy , Cell- and Tissue-Based Therapy/methods , Liver Transplantation , Liver Failure, Acute/surgery , Tissue Preservation/methods , Cryopreservation , Hepatocytes/transplantationABSTRACT
Introducción. 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. Métodos. 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. Resultados. 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. Conclusión. 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 (AU)
Introduction. 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. Methods. 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. Results. 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. Conclusion. 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 (AU)
Subject(s)
Rats , Animals , Hepatocytes/virology , Adenoviridae/pathogenicity , Lipoproteins, VLDL , Adenoviridae Infections/immunology , Cholesterol Esters/analysis , Hepatocytes , Lipids/immunologyABSTRACT
Cultured hepatocytes from rat, rabbit, calf, pig, and sheep were used to study metabolism and formation of protein-bound residues of thiabendazole ([(14)C]TBZ), a benzimidazole anthelmintic and fungicide. In all investigated species, major pathways corresponded to 5-hydroxylation of TBZ and its further conjugation. However, marked interspecies differences in rates of TBZ disappearance and 5-hydroxy metabolite formation were demonstrated. Rabbit hepatocytes presented the fastest TBZ biotransformation and were the most extensive hydroxylators. By contrast, the lowest capacity of oxidation was observed for the rat. Two unidentified minor metabolites, designated M1 and M2, were particularly produced by sheep hepatocytes. Moreover, the protein-bound residues in these cells, which could be related to cytochrome P450-dependent oxidation, were formed in 4 times greater amounts than in the other animal cells. These findings substantiate hepatocytes as an in vitro model for prediction of hepatic metabolism in vivo.
