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Barcelona, Spain

Guevara M.,Liver Unit Hospital Clinic | Guevara M.,Institute dInvestigacions Biomediques August Pi Sunyer
Hepatology | Year: 2012

Aims: In patients with cirrhosis and refractory ascites the role of beta-blockers in the development of paracentesis- induced circulatory dysfunction (PICD) is unknown. The aim of this study was to investigate the incidence of PICD before and after discontinuation of beta- blockers in patients with cirrhosis and refractory ascites. A self control cross-over study was performed. Methods: Patients with cirrhosis and refractory ascites treated with beta-blockers were selected. Heart rate, arterial pressure, and plasma renin concentrations (PRC) were collected before, immediately after and 1 week after largevolume paracentesis associated with intravenous albumin administration. Beta-blocker therapy was progressively discontinued after complete endoscopic eradication of varices. The clinical and biological evaluation was then repeated. The presence of PICD was defined as an increase in PRC of at least 50% above baseline 1 week after paracentesis. Results: Ten patients were included (nine men, mean age 59.1 6 10.7 years old). The MELD score was 17.7 6 4.4 and eight patients were Child Pugh C. When patients were given betablockers,the heart rate did not change immediately after paracentesis while mean arterial pressure significantly decreased; PICD developed in eight patients. After beta-blockers were discontinued, the heart rate significantly increased immediately after paracentesis and mean arterial pressure significantly decreased; PICD only developed in one patient; the difference in the incidence of PICD was significant when these same patients were treated with beta-blockers. Conclusions: The use of beta-blockers may be associated with a high risk of PICD in patients with cirrhosis and refractory ascites. © 2012. Source

Montfort C.V.,Liver Unit Hospital Clinic | Montfort C.V.,CIBER ISCIII | Matias N.,Liver Unit Hospital Clinic | Matias N.,CIBER ISCIII | And 18 more authors.
Journal of Hepatology | Year: 2012

Background & Aims: Steatohepatitis (SH) is associated with mitochondrial dysfunction and excessive production of superoxide, which can then be converted into H2O2 by SOD2. Since mitochondrial GSH (mGSH) plays a critical role in H2O2 reduction, we explored the interplay between superoxide, H2O2, and mGSH in nutritional and genetic models of SH, which exhibit mGSH depletion. Methods: We used isolated mitochondria and primary hepatocytes, as well as in vivo SH models showing mGSH depletion to test the consequences of superoxide scavenging. Results: In isolated mitochondria and primary hepatocytes, superoxide scavenging by SOD mimetics or purified SOD decreased superoxide and peroxynitrite generation but increased H2O2 following mGSH depletion, despite mitochondrial peroxiredoxin/thioredoxin defense. Selective mGSH depletion sensitized hepatocytes to cell death induced by SOD mimetics, and this was prevented by RIP1 kinase inhibition with necrostatin-1 or GSH repletion with GSH ethyl ester (GSHee). Mice fed the methionine-choline deficient (MCD) diet or MAT1A-/- mice exhibited reduced SOD2 activity; in vivo treatment with SOD mimetics increased liver damage, inflammation, and fibrosis, despite a decreased superoxide and 3-nitrotyrosine immunoreactivity, effects that were ameliorated by mGSH replenishment with GSHee, but not NAC. As a proof-of-principle of the detrimental role of superoxide scavenging when mGSH was depleted transgenic mice overexpressing SOD2 exhibited enhanced susceptibility to MCD-mediated SH. Conclusions: These findings underscore a critical role for mGSH in the therapeutic potential of superoxide scavenging in SH, and suggest that the combined approach of superoxide scavenging with mGSH replenishment may be important in SH. © 2012 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved. Source

Mari M.,Liver Unit Hospital Clinic | Morales A.,Liver Unit Hospital Clinic | Colell A.,Liver Unit Hospital Clinic | Garcia-Ruiz C.,Liver Unit Hospital Clinic | And 3 more authors.
Biochimica et Biophysica Acta - General Subjects | Year: 2013

Background: Mitochondria are the powerhouse of mammalian cells and the main source of reactive oxygen species (ROS) associated with oxygen consumption. In addition, they also play a strategic role in controlling the fate of cells through regulation of death pathways. Mitochondrial ROS production fulfills a signaling role through regulation of redox pathways, but also contributes to mitochondrial damage in a number of pathological states. Scope of review: Mitochondria are exposed to the constant generation of oxidant species, and yet the organelle remains functional due to the existence of an armamentarium of antioxidant defense systems aimed to repair oxidative damage, of which mitochondrial glutathione (mGSH) is of particular relevance. Thus, the aim of the review is to cover the regulation of mGSH and its role in disease. Major conclusions: Cumulating evidence over recent years has demonstrated the essential role for mGSH in mitochondrial physiology and disease. Despite its high concentration in the mitochondrial matrix, mitochondria lack the enzymes to synthesize GSH de novo, so that mGSH originates from cytosolic GSH via transport through specific mitochondrial carriers, which exhibit sensitivity to membrane dynamics. Depletion of mGSH sensitizes cells to stimuli leading to oxidative stress such as TNF, hypoxia or amyloid β-peptide, thereby contributing to disease pathogenesis. General significance: Understanding the regulation of mGSH may provide novel insights to disease pathogenesis and toxicity and the opportunity to design therapeutic targets of intervention in cell death susceptibility and disease. This article is part of a Special Issue entitled Cellular functions of glutathione. © 2012 Elsevier B.V. Source

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