FDG PET and MR imaging in patients with liver metastases from uveal melanoma : results from a pilot study

Le présent travail a eu comme but la comparaison de la performance de deux méthodes d'imagerie diagnostique pour la détection de métastases hépatiques du mélanome uvéal : la tomographie d'émission par positons au F-18-fluorodésoxyglucose (TEP FDG) couplée à la tomodensitométrie (TDM) et l'imagerie par résonance magnétique (IRM). Dans cette étude rétrospective, nous avons analysé les données radiologiques de patients inclus dans une étude multicentrique randomisée de phase III de l'Uveal Melanoma Group of the European Organization for Research and Treatment of Cancer (EORTC). L'IRM s'est révélée nettement plus sensible que le FDG-PET/CT pour mettre en évidence les métastases hépatiques notamment de taille infra-centimétrique. Néanmoins, l'analyse des changements de l'accumulation du traceur métabolique par les métastases hépatiques au cours du traitement suggère la possibilité d'évaluer, de manière précoce, la réponse des métastases hépatiques à la chimiothérapie. Le nombre de cas étudiés est trop faible pour déterminer la précision et la valeur clinique d'une telle évaluation mais les résultats obtenus dans cette étude pilote justifient une étude plus étendue.

Transcriptional regulation by triiodothyronine of the UDP-glucuronosyltransferase family 1 gene complex in rat liver. Comparison with induction by 3-methylcholanthrene.

This study demonstrates that the expression of the phenol UDP-glucuronosyltransferase 1 gene (UGT1A1) is regulated at the transcriptional level by thyroid hormone in rat liver. Following 3,5, 3'-triiodo-L-thyronine (T3) stimulation in vivo, there is a gradual increase in the amount of UGT1A1 mRNA with maximum levels reached 24 h after treatment. In comparison, induction with the specific inducer, 3-methylcholanthrene (3-MC), results in maximal levels of UGT1A1 mRNA after 8 h of treatment. In primary hepatocyte cultures, the stimulatory effect of both T3 and 3-MC is also observed. This induction is suppressed by the RNA synthesis inhibitor actinomycin D, indicating that neither inducer acts at the level of mRNA stabilization. Indeed, nuclear run-on assays show a 3-fold increase in UGT1A1 transcription after T3 treatment and a 6-fold increase after 3-MC stimulation. This transcriptional induction by T3 is prevented by cycloheximide in primary hepatocyte cultures, while 3-MC stimulation is only partially affected after prolonged treatment with the protein synthesis inhibitor. Together, these data provide evidence for a transcriptional control of UGT1A1 synthesis and indicate that T3 and 3-MC use different activation mechanisms. Stimulation of the UGT1A1 gene by T3 requires de novo protein synthesis, while 3-MC-dependent activation is the result of a direct action of the compound, most likely via the aromatic hydrocarbon receptor complex.

Complementary DNA cloning of complement C8 beta and its sequence homology to C9.

The complete amino acid sequence of mature C8 beta has been derived from the DNA sequence of a cDNA clone identified by expression screening of a human liver cDNA library. Comparison with the amino acid sequence of C9 shows an overall homology with few deletions and insertions. In particular, the cysteine-rich domains and membrane-inserting regions of C9 are well conserved. These findings are discussed in relation to a possible mechanism of membrane attack complex formation.

Paired activation of two components within muscarinic M3 receptor dimers is required for recruitment of beta-arrestin-1 to the plasma membrane.

beta-Arrestins regulate the functioning of G protein-coupled receptors in a variety of cellular processes including receptor-mediated endocytosis and activation of signaling molecules such as ERK. A key event in these processes is the G protein-coupled receptor-mediated recruitment of beta-arrestins to the plasma membrane. However, despite extensive knowledge in this field, it is still disputable whether activation of signaling pathways via beta-arrestin recruitment entails paired activation of receptor dimers. To address this question, we investigated the ability of different muscarinic receptor dimers to recruit beta-arrestin-1 using both co-immunoprecipitation and fluorescence microscopy in COS-7 cells. Experimentally, we first made use of a mutated muscarinic M(3) receptor, which is deleted in most of the third intracellular loop (M(3)-short). Although still capable of activating phospholipase C, this receptor loses almost completely the ability to recruit beta-arrestin-1 following carbachol stimulation in COS-7 cells. Subsequently, M(3)-short was co-expressed with the M(3) receptor. Under these conditions, the M(3)/M(3)-short heterodimer could not recruit beta-arrestin-1 to the plasma membrane, even though the control M(3)/M(3) homodimer could. We next tested the ability of chimeric adrenergic muscarinic alpha(2)/M(3) and M(3)/alpha(2) heterodimeric receptors to co-immunoprecipitate with beta-arrestin-1 following stimulation with adrenergic and muscarinic agonists. beta-Arrestin-1 co-immunoprecipitation could be induced only when carbachol or clonidine were given together and not when the two agonists were supplied separately. Finally, we tested the reciprocal influence that each receptor may exert on the M(2)/M(3) heterodimer to recruit beta-arrestin-1. Remarkably, we observed that M(2)/M(3) heterodimers recruit significantly greater amounts of beta-arrestin-1 than their respective M(3)/M(3) or M(2)/M(2) homodimers. Altogether, these findings provide strong evidence in favor of the view that binding of beta-arrestin-1 to muscarinic M(3) receptors requires paired stimulation of two receptor components within the same receptor dimer.

Long-Term Follow-Up of Multilayer Amniotic Membrane Transplantation (MLAMT) for Non-Traumatic Corneal Perforations or Deep Ulcers with Descemetocele.

Background: To evaluate the long-term efficacy of multilayer amniotic membrane transplantation for reconstruction of epithelium and stroma in non-traumatic corneal perforations (less than 2 mm) or deep ulcers with descemetocele.Design: Retrospective, non-comparative, interventional case series.Patients and Methods: Eleven consecutive patients with non-traumatic corneal perforations or deep corneal ulcers with descemetocele refractory to conventional treatments: herpetic or zoster keratitis (n = 4), Sjögren's syndrome (n = 2), rosacea (n = 1), hydrops (n = 1), mucous membrane pemphigoid (n = 1), bacterial keratitis (n = 1) and perforation after protontherapy for melanoma (n = 1). Intervention was: multilayer amniotic membrane transplantation with cryopreserved amniotic membrane. Complication rate and clinical outcome were evaluated in this long-term follow-up.Results: Mean follow-up was 32 months (12 to 60). Integration of the multilayer amniotic membrane was obtained in 10 cases after one year. Corneal epithelium healed above the membrane in 10 cases within 3 weeks and remained stable after 32 months in 9 cases. Thickness of the stroma was increased and remained stable during the follow-up in 9 cases. In one case herpetic keratitis recurred with a corneal perforation. The clearing of the amniotic membrane was gradually obtained over a period of 11 months. Complications occurred in 15 % of the eyes during the long-term follow-up.Conclusion: Multilayer amniotic membrane transplantation is a safe and efficient technique for a long restoration of the corneal integrity after non-traumatic corneal perforations or deep corneal ulcers with descemetocele. Long-term prognosis of these eyes depends of the gravity of the initial disease.

Thymus-independent generation of NK1+ T cells in vitro from fetal liver precursors.

NK1.1+TCR alpha beta+ (NK1+) T cells are an unusual subset of mouse TCR alpha beta+ cells found primarily in adult thymus and liver. In contrast to conventional TCR alpha beta+ cells, NK1+ T cells have a TCR repertoire that is highly skewed to V alpha14 and to Vbeta8, -7, and -2. The developmental origin and ligand specificity of NK1+ T cells are controversial. We show here that NK1+ T cells with a typically biased V alpha and V beta repertoire develop in cytokine-supplemented suspension cultures of fetal liver established from either normal or athymic mice. Furthermore, NK1+ T cell development in fetal liver cultures is abrogated in beta2m-deficient mice (which lack MHC class I and other related molecules) and can be partially inhibited by the presence of anti-CD1 mAbs. Moreover, mixing experiments indicate that recombination-deficient SCID fetal liver cells can reconstitute NK1+ T cell development in beta2m-deficient fetal liver cultures. Collectively, our data demonstrate that NK1+ T cells can develop extrathymically from fetal liver precursors and that a beta2m-associated ligand (putatively CD1) present on nonlymphoid cells is essential for their positive selection and/or expansion.

Métabolisme d'antidépresseurs dans différentes espèces : aspects méthodologiques et pharmacogénétiques, perspectives cliniques

Résumé pour large public Unité de Biochimie et Psychopharmacologie Clinique, Centre de neurosciences Psychiatrique, Département de Psychiatrie Adulte, Faculté de Biologie et de Médecine, Université de Lausanne Lors de la prise d'un médicament, celui-ci va passer par différentes étapes que sont l'absorption, la distribution, le métabolisme et enfin l'élimination. Ces quatre étapes sont regroupées sous le nom de pharmacocinétique. A noter que ces quatre paramètres sont dynamiques et en constante évolution. Durant cette thèse, nous avons investigué différents aspects de la pharmacocinétique, tout d'abord par une revue de la littérature sur la glycoprotéine-P (Pgp). Récemment découverte, cette protéine de membrane est située aux endroits stratégiques de l'organisme comme la barrière hématoencéphalée, le placenta ou les intestins où elle influencera l'entrée de différentes substances, en particulier les médicaments. La Pgp serait impliquée dans les phénomènes de résistances aux agents thérapeutiques en oncologie. La Pgp influence donc l'absorption des médicaments, et son impact en clinique, en termes d'efficacité de traitement et de toxicité prend chaque jour plus d'importance. Ensuite nous avons mis au point une méthode d'analyse quantitative d'un antidépresseur d'une nouvelle génération : la mirtazapine (Remeron®). La nouveauté réside dans la façon dont la mirtazapine interagit avec les neurotransmetteurs impliqués dans la dépression que sont la sérotonine et la noradrénaline. Cette méthode utilise la chromatographie liquide pour séparer la mirtazapine de ses principaux métabolites dans le sang. La spectrométrie de masse est utilisée pour les détecter et les quantifier. Les métabolites sont des substances issues de réactions chimiques entre la substance mère, la mirtazapine, et généralement des enzymes hépatiques, dans le but de rendre cette substance plus soluble en vue de son élimination. Cette méthode permet de quantifier la mirtazapine et ses métabolites dans le sang de patients traités et de déterminer la variation des taux plasmatiques chez ces patients. Puis nous avons étudié le métabolisme d'un autre antidépresseur, le citalopram, qui a un métabolisme complexe. Le citalopram est un racémate, c'est-à-dire qu'il existe sous forme de deux entités chimiques (R-(-) et S-(+) citalopram) qui ont le même nombre d'éléments mais arrangés différemment dans l'espace. La voie métabolique cérébrale du citalopram est sous le contrôle d'une enzyme, la monoamine oxydase (MAO), conduisant à une forme acide du citalopram (l'acide propionique du citalopram). La MAO existe sous deux formes : MAO-A et MAO-B. Nous avons utilisé des souris déficientes d'un gène, celui de la MAO-A, pour mieux en comprendre le métabolisme en les comparants à des souris sauvages (sans déficience de ce gène). Nous avons utilisé le citalopram et deux de ses métabolites (le déméthylcitaloprarn et le didéméthyícitalopram) comme substrats pour tester la formation in vitro de l'acide propionique du citalopram. Nos résultats montrent que la MAO-A favorise la formation de l'entité R-(-) et présente une plus grande affinité pour le citalopram, tandis que la MAO-B métabolise préférentiellement l'entité S-(+) et a une plus grande affinité pour les deux métabolites déméthylés. De plus, la déficience en MAO-A est partiellement compensée parla MAO-B chez les souris déficientes du gène de la MAO-A. Enfin, nous avons étudié une deuxième voie métabolique du citalopram qui s'est avérée toxique chez le chien Beagle. Celle-ci est catalysée par une autre famille d'enzymes, les cytochromes P-450, et mène aux métabolites déméthylés et didéméthylés du citalopram. Nous avons utilisé des tissus hépatiques de chiens Beagle. Plusieurs cytochromes P-450 sont impliqués dans le métabolisme du citalopram menant à sa forme déméthylée, ceci tant chez l'homme que chez le chien. Par contre, dans le métabolisme de la forme déméthylée menant à 1a forme didéméthylée, un seul cytochrome P-450 serait impliqué chez l'Homme, tandis qu'ils seraient plusieurs chez le chien. L'activité enzymatique produisant la forme didéméthylée est beaucoup plus importante chez le chien comparé à l'homme. Cette observation soutien l'hypothèse que des taux élevés de la forme didéméthylée participent à la toxicité spécifique du citalopram chez le chien. Nous pouvons conclure que plusieurs famille d'enzymes sont impliquées tant au niveau cérébral qu'hépatique dans la métabolisation de médicaments psychotropes. Sachant que les enzymes peuvent être stimulées ou inhibées, il importe de pouvoir suivre au plus prés les taux plasmatiques des différents psychotropes et de leurs métabolites. Résumé Unité de Biochimie et Psychopharmacologie Clinique, Centre de neurosciences Psychiatrique, Département de Psychiatrie Adulte, Faculté de Biologie et de Médecine, Université de Lausanne La plupart des médicaments subissent une transformation enzymatique dans l'organisme. Les substances issues de cette métabolisation ne sont pas toujours dotées d'une activité pharmacologique. Il s'est avéré par conséquent indispensable de suivre les taux plasmatiques d'une substance et de ses métabolites et d'établir ou non l'existence d'une relation avec l'effet clinique observé. Ce concept nommé « therapeutic drag monitoring » (TDM) est particulièrement utile en psychiatrie ou un manque de compliance des patients est fréquemment observé. Les médicaments psychotropes ont un métabolisme principalement hépatique (cytochromes P-450) et parfois cérébral (monoamines oxydases), comme pour le citalopram par exemple. Une méthode stéréosélective de chromatographie liquide couplée à la spectrométrie de masse a été développée pour analyser les énantiomères R-(-) et S-(+) d'un antidépresseur agissant sur les récepteurs noradrénergiques et sérotoninergiques, la mirtazapine et de ses métabolites déméthylmirtazapine et 8-hydroxymirtazapine. Les données préliminaires obtenues dans les plasmas dosés suggèrent que les concentrations de R-(-)-mirtazapine sont plus élevées que celles de S-(+)-mirtazapine, à l'exception des patients qui auraient comme co-médication des inhibiteurs du CYP2D6, telle que la fluoxétine ou la thioridazine. Il y a une enantiosélectivité du métabolisme de la mirtazapine. En particulier pour la 8-hydroxymirtazapine qui est glucuroconjuguée et pour laquelle le ratio S/R varie considérablement. Cette méthode analytique présente l'avantage d'être utilisable pour le dosage stéréosélectif de la mirtazapine et de ses métabolites dans le plasma de patients ayant d'autres substances en co-médication. La glycoprotéine P fonctionne comme une pompe transmembranaire transportant les xénobiotiques depuis le milieu intracellulaire vers le milieu extracellulaire. Son induction et son inhibition, bien que moins étudiées que pour les cytochromes P-450, ont des implications cliniques importantes en termes d'efficacité de traitement et de toxicité. Cette glycoprotéine P a fait l'objet d'une recherche bibliographique. Nous avons étudié le métabolisme du citalopram, un antidépresseur de la classe des inhibiteurs spécifiques de la recapture de la sérotonine chez la souris et chez le chien. Cette substance subit un métabolisme complexe. La voie de métabolisation conduisant à la formation de l'acide propionique du citalopram, catalysée par les monoamines oxydases, a été étudiée in vitro dans les mitochondries cérébrales chez la souris déficiente du gène de la MAO-A (Tg8). La monoamine oxydase A catalyse la formation de l'énantiomère R-(-) et présente une plus grande affinité pour les amines tertiaires, tandis que la monoamine oxydase B favorise la formation de la forme S-(+) et a une affinité plus marquée pour les amines secondaires et primaires. L'étude du citalopram chez la souris Tg8 adulte a montré que la monoamine oxydase B compense la déficience de la monoamine oxydase A chez ces souris génétiquement modifiées. Une autre voie de métabolisation du citalopram conduisant à la formation de didéméthylcitalopram, catalysée par les cytochromes P-450, a été étudiée in vitro dans des microsomes hépatiques de chiens Beagle. Nos études ont montré que les cinétiques de N-déméthylation du citalopram sont biphasiques chez le chien. Les orthologues canins impliqués dans la première N-déméthylation semblent être identiques aux cytochromes P-450 humains. Par contre, dans la deuxième Ndéméthylation, un seul cytochrome P-450 semble être impliqué chez l'homme (CYP2D6), tandis qu'on retrouve jusqu'à cinq orthologues chez le chien. Le CYP2D15, orthologue canin du CYP2D6, est majoritairement impliqué. De plus, l'activité enzymatique, reflétée par les clairances intrinsèques, dans la première N-déméthylation est jusqu'à 45 fois plus élevée chez le chien comparé à l'homme. Ces différentes observations soutiennent l'hypothèse que des taux élevés de didéméthylcitalopram sont responsables de la toxicité du citalopram chez le chien. Nous pouvons conclure que plusieurs famille d'enzymes sont impliquées tant au niveau cérébral qu'hépatique dans la métabolisation de médicaments psychotropes. Sachant -que les enzymes peuvent être induits ou inhibés, il importe de pouvoir suivre au plus près les taux plasmatiques des différents psychotropes et de leurs métabolites. Summary Most of the drugs are metabolized in the organism. Substances issued from this metabolic activity do not always show a pharmacological activity. Therefore, it is necessary to monitor plasmatic levels of drugs and their metabolites, and establish the relationship with the clinical effect. This concept named therapeutic drug monitoring is very useful in psychiatry where lack of compliance is commonly observed. Antidepressants are mainly metabolized in the liver (cytochrome P-450) and sometimes in the brain (monoamine oxidase) like the citalopram, for exemple. A LC-MS method was developed, which allows the simultaneous analysis of R-(-) and S-(+) enantiomers of mirtazapine, an antidepressant acting specifically on noradrenergic and serotonergic receptors, and its metabolites demethylmirtazapine and 8-hydroxymirtazapine in plasma of mirtazapine treated patients. Preliminary data obtained suggested that R-(-) mirtazapine concentrations were higher than those of S-(+) mirtazapine, except in patients comedicated with CYP2D6 inhibitors such as fluoxetine or thioridazine. There is an enantioselectivity in the metabolism of mirtazapine. In particular for the 8-hydroxymirtazapine, which is glucuroconjugated and S/R ratio varies considerably. Therefore this method seems to be suitable for the stereoselective assay of mirtazapine and its metabolites in plasma of patients comedicated with mirtazapine and other drugs for routine and research purposes. P-glycoprotein is working as an efflux transporter of xenobiotics from intracellular to extracellular environment. Its induction or inhibition, although less studied than cytochrome P-450, has huge clinical implications in terms of treatment efficacy and toxicity. An extensive literature search on P-glycoprotein was performed as part of this thesis. The study of citalopram metabolism, an antidepressant belonging to the class of selective serotonin reuptake inhibitors. This substance undergoes a complex metabolism. First metabolization route leading to citalopram propionic acid, catalyzed by monoamine oxidase was studied in vitro in mice brain mitochondria. Monoamine oxidase A catalyzed the formation of R-(-) enantiomer and showed greater affinity for tertiary amines, whereas monoamine oxidase B triggered the formation of S-(+) enantiomer and demonstrated higher affinity for primary and secondary amines. citalopram evaluation in adult Tg8 mice showed that monoamine oxidase B compensated monoamine oxidase A deficiency in those genetically transformed mice. The second metabolization route of citalopram leading to didemethylcitalopram and catalyzed by cytochrome P-450 was studied in vitro in Beagle dog's livers. Our results showed that citalopram N-demethylation kinetics are biphasic in dogs. Canine orthologs involved in the first N-demethylation seemed to be identical to human cytochromes P-450. However, in the second N-demethylation only one cytochrome P-450 seemed to be involved in human (CYP2D6), whereas up to five canine orthologs were found in dogs. CYP2D15 canine ortholog of CYP2D6 was mainly involved. In addition, enzymatic activity reflected by intrinsic clearance in the first N-demethylation was up to 45 fold higher in dogs compared to humans. Those observations support the assumption that elevated rates of didemethylcitalopram are responsible for citalopram toxicity in dogs. We can conclude that several enzymes groups are involved in the brain, as well as in the liver, in antidepressant metabolization. Knowing that enzymes may be induced or inhibited, it makes sense to closely monitor plasmatic levels of antidepressants and their metabolites.

Poly (ADP-ribose) polymerase-1 is a key mediator of liver inflammation and fibrosis.

Poly (ADP-ribose) polymerase 1 (PARP-1) is a constitutive enzyme, the major isoform of the PARP family, which is involved in the regulation of DNA repair, cell death, metabolism, and inflammatory responses. Pharmacological inhibitors of PARP provide significant therapeutic benefits in various preclinical disease models associated with tissue injury and inflammation. However, our understanding the role of PARP activation in the pathophysiology of liver inflammation and fibrosis is limited. In this study we investigated the role of PARP-1 in liver inflammation and fibrosis using acute and chronic models of carbon tetrachloride (CCl4 )-induced liver injury and fibrosis, a model of bile duct ligation (BDL)-induced hepatic fibrosis in vivo, and isolated liver-derived cells ex vivo. Pharmacological inhibition of PARP with structurally distinct inhibitors or genetic deletion of PARP-1 markedly attenuated CCl4 -induced hepatocyte death, inflammation, and fibrosis. Interestingly, the chronic CCl4 -induced liver injury was also characterized by mitochondrial dysfunction and dysregulation of numerous genes involved in metabolism. Most of these pathological changes were attenuated by PARP inhibitors. PARP inhibition not only prevented CCl4 -induced chronic liver inflammation and fibrosis, but was also able to reverse these pathological processes. PARP inhibitors also attenuated the development of BDL-induced hepatic fibrosis in mice. In liver biopsies of subjects with alcoholic or hepatitis B-induced cirrhosis, increased nitrative stress and PARP activation was noted. CONCLUSION: The reactive oxygen/nitrogen species-PARP pathway plays a pathogenetic role in the development of liver inflammation, metabolism, and fibrosis. PARP inhibitors are currently in clinical trials for oncological indications, and the current results indicate that liver inflammation and liver fibrosis may be additional clinical indications where PARP inhibition may be of translational potential.

Risk Factors for Incisional and Organ Space Surgical Site Infections After Liver Resection are Different.

BACKGROUND: Surgical site infection (SSI) is a common cause of major morbidity after liver resection. This study aimed to identify the risk factors for incisional and organ/space SSIs after liver resection. METHODS: Our liver surgery database was retrospectively analyzed for patients treated between January 2009 and November 2012 in a tertiary care Swiss hospital. Univariate and multivariate analyses were conducted on preoperative, intraoperative, and postoperative variables to identify risk factors for incisional and organ/space SSIs. RESULTS: In a total of 226 patients, SSI incidences were 12.8 % (incisional), 4.0 % (organ/space), and 1.8 % (both). Univariate analysis showed that incisional SSIs were associated with high American Society of Anesthesiologists (ASA) scores, preoperative anemia, hypoalbuminemia, low prothrombin time, viral or alcoholic chronic hepatitis, liver cirrhosis, and prolonged operation times. Organ/space SSIs were associated with high rates of red blood cell transfusions, concomitant bowel surgery, and prolonged operation times. Multivariate analysis revealed that risk factors for incisional SSIs were anemia [odds ratio (OR) 2.82], high ASA scores (OR 2.88), presence of hepatitis or cirrhosis (OR 5.07), and prolonged operation times (OR 9.61). The only risk factor for organ/space SSIs was concomitant bowel surgery (OR 5.53). Hospital stays were similar in organ/space and incisional SSI groups, but significantly longer for those with both organ/space and incisional SSIs. CONCLUSIONS: High ASA scores, anemia, chronic hepatitis or liver cirrhosis, and prolonged operations increased the risk of incisional SSIs; concomitant bowel surgery increased the risk of organ/space SSI. Specific precautions to prevent organ/space and incisional SSIs may shorten hospital stays.

Is magnetic resonance imaging of hepatic hemangioma any different in liver fibrosis and cirrhosis compared to normal liver?

PURPOSE: To compare qualitative and quantitative magnetic resonance (MR) imaging characteristics of hepatic hemangiomas in patients with normal, fibrotic and cirrhotic livers. MATERIALS AND METHODS: Retrospective, institutional review board approved study (waiver of informed consent). Eighty-nine consecutive patients with 231 hepatic hemangiomas who underwent liver MR imaging for lesion characterization were included. Lesions were classified into three groups according to the patients' liver condition: no underlying liver disease (group 1), fibrosis (group 2) and cirrhosis (group 3). Qualitative and quantitative characteristics (number, size, signal intensities on T1-, T2-, and DW MR images, T2 shine-through effect, enhancement patterns (classical, rapidly filling, delayed filling), and ADC values) were compared. RESULTS: There were 160 (69%), 45 (20%), and 26 (11%) hemangiomas in groups 1, 2 and 3, respectively. Lesions were larger in patients with normal liver (group 1 vs. groups 2 and 3; P=.009). No difference was found between the groups on T2-weighted images (fat-suppressed fast spin-echo (P=.82) and single-shot (P=.25)) and in enhancement patterns (P=.56). Mean ADC values of hemangiomas were similar between groups 1, 2 and 3 (2.11±.52×10(-3)mm(2)/s, 2.1±.53×10(-3)mm(2)/s and 2.14±.44×10(-3)mm(2)/s, P=87, respectively). T2 shine-through effect was less frequently observed in cirrhosis (P=.02). CONCLUSION: MR imaging characteristics of hepatic hemangioma were similar in patients with normal compared to fibrotic and cirrhotic livers. Smaller lesion size was observed with liver disease and less T2 shine-through effect was seen in hemangiomas developed on cirrhosis, the latter being an important finding to highlight in these patients at risk of developing hepatocellular carcinoma.

Liver-specific loss of lipin-1-mediated phosphatidic acid phosphatase activity does not mitigate intrahepatic TG accumulation in mice.

Lipin proteins (lipin 1, 2, and 3) regulate glycerolipid homeostasis by acting as phosphatidic acid phosphohydrolase (PAP) enzymes in the TG synthesis pathway and by regulating DNA-bound transcription factors to control gene transcription. Hepatic PAP activity could contribute to hepatic fat accumulation in response to physiological and pathophysiological stimuli. To examine the role of lipin 1 in regulating hepatic lipid metabolism, we generated mice that are deficient in lipin-1-encoded PAP activity in a liver-specific manner (Alb-Lpin1(-/-) mice). This allele of lipin 1 was still able to transcriptionally regulate the expression of its target genes encoding fatty acid oxidation enzymes, and the expression of these genes was not affected in Alb-Lpin1(-/-) mouse liver. Hepatic PAP activity was significantly reduced in mice with liver-specific lipin 1 deficiency. However, hepatocytes from Alb-Lpin1(-/-) mice had normal rates of TG synthesis, and steady-state hepatic TG levels were unaffected under fed and fasted conditions. Furthermore, Alb-Lpin1(-/-) mice were not protected from intrahepatic accumulation of diacylglyerol and TG after chronic feeding of a diet rich in fat and fructose. Collectively, these data demonstrate that marked deficits in hepatic PAP activity do not impair TG synthesis and accumulation under acute or chronic conditions of lipid overload.

Sofosbuvir and ribavirin before liver re-transplantation for graft failure due to recurrent hepatitis C: a case report.

BACKGROUND: Recurrent hepatitis C virus infection after liver transplantation is associated with reduced graft and patient survival. Re-transplantation for graft failure due to recurrent hepatitis C is controversial and not performed in all centers. CASE PRESENTATION: We describe a 54-year-old patient with hepatitis C virus genotype 1b infection and a null response to pegylated interferon-α and ribavirin who developed decompensated graft cirrhosis 6 years after a first liver transplantation. Treatment with sofosbuvir and ribavirin allowed for rapid negativation of serum HCV RNA and was well tolerated despite advanced liver and moderate renal dysfunction. Therapeutic drug monitoring did not reveal any clinically significant drug-drug interactions. Despite virological response, the patient remained severely decompensated and re-transplantation was performed after 46 days of undetectable serum HCV RNA. The patient is doing well 12 months after his second liver transplantation and remains free of hepatitis C virus. CONCLUSIONS: The use of directly acting antivirals may allow for successful liver re-transplantation for recipients who remain decompensated despite virological response and is likely to improve the outcome of liver re-transplantation for end-stage recurrent hepatitis C.