Sustained activation of the Raf/MEK/Erk pathway in response to EGF in stable cell lines expressing the Hepatitis C Virus (HCV) core protein.

Chronic hepatitis C virus (HCV) infection is a leading cause of liver cirrhosis and hepatocellular carcinoma (HCC) worldwide. The HCV capside core is a multifunctional protein with regulatory functions that affects transcription and cell growth in vitro and in vivo. Here, we show that both HCV genotype 1a and 3 core proteins activate MEK1 and Erk1/2 MAP kinases and that the costitutive expression of the HCV core results in a high basal activity of Raf1 and MAP/kinase/kinase, as determined by endogenous Raf1 in vitro kinase assay and immunodetection of hyperphosphorylated Erk1 and Erk2 even after a serum starvation. Moreover, the activation of both Erk1/2 and the downstream transcription factor Elk-1 in response to the mitogenic stimulus EGF is significantly prolonged. The sustained response to EGF in cells expressing the HCV core occurs despite a normal induction of the MAP phosphatases MKP regulatory feedback and is likely due to the costitutive activation of Raf-1 activity. The ability of HCV core proteins to directly activate the MAP kinase cascade and to prolong its activity in response to mitogenic stimuli may contribute to the neoplastic transformation of HCV infected liver cells.

Nonsteroidal anti-inflammatory drug metabolism potentiates interferon alfa signaling by increasing STAT1 phosphorylation.

A sustained response to standard interferon therapy for chronic hepatitis C has been demonstrated in no more than 25% of patients. To improve interferon alfa (IFN-alpha) antiviral effect, a number of combination therapies with IFNs plus other drugs have been proposed for both relapser and nonresponder hepatitis C virus (HCV)-infected patients. Although the causes of IFN resistance in subsets of HCV-infected patients are unknown, both viral and host factors have been involved, including defects in IFN signal transduction and IFN-alpha/beta receptor down-regulation. Here, we report that nonsteroidal anti-inflammatory drugs (NSAIDs), which have been proposed for IFN-alpha combination therapy in nonresponders, potentiate IFN-alpha signaling. We found that, in the hepatoma cell lines, CCL13/Chang and HepG2, indomethacin, a selective cyclo-oxygenase 1 and 2 (COX-1 and COX-2) inhibitor, increases IFN-alpha stimulation of interferon-stimulated response element (ISRE)-dependent transcription in a dose-dependent manner. Interestingly, maximal potentiation was observed with suboptimal IFN-alpha concentrations. Indomethacin exerts its effects by synergizing with IFN-alpha in inducing STAT1 activation by phosphorylation, without affecting concurrent Jak1 phosphorylation. Our data indicate that blockade of arachidonic acid (AA) metabolism by indomethacin activates a signaling pathway that converges on STAT1 activation to potentiate IFN-alpha-dependent gene activation.

Treatment of congenital afibrinogenemia with cryoprecipitate collected through a plasmapheresis program using dedicated donors.

A child with afibrinogenemia was evaluated for prophylactic cryoprecipitate transfusion due to recurrent episodes of traumatic bleeding. The parents would only consider ongoing transfusion therapy if a limited donor program could be established. Automated plasmapheresis was performed on a regular basis on the patient's parents and a limited number of selected donors. Studies on the initial units collected demonstrated that a single 500 mL plasmapheresis yielded a mean of 606 mg fibrinogen in the cryoprecipitate, which was stored in two bags. A total of 166 U of cryoprecipitate from 84 individual plasmapheresis donations were transfused prophylactically every 2-3 weeks over a 16-month period. Compared to transfusions from random donors, the use of a limited number of apheresis donors resulted in a donor exposure reduction of 87%. Clinically, the patient has had minimal bleeding during this period.

Iron overload in patients with chronic viral hepatitis: how common is it?

OBJECTIVES: To establish the prevalence of increased hepatic iron content in patients with hepatitis C virus-related chronic hepatitis and to assess the accuracy of serum iron and ferritin in detecting tissue iron overload. METHODS: Serum iron, serum ferritin, and hepatic iron content were determined in 81 consecutive patients undergoing liver biopsy for chronic ALT elevation and hepatitis C virus infection. Moreover, in a subgroup of 28 patients, outcome of a 6-month course of interferon (IFN) treatment (6 million U of recombinant IFN, three times weekly) was determined after a mean follow-up of 24 +/- 6 months and the outcome was compared with the pretreatment values of hepatic iron content. RESULTS: Elevated serum iron or ferritin levels were detected in approximately 40% of patients, but elevated hepatic iron content was observed in only eight patients (10%). One of these patients had a hepatic iron index > 1.9, indicating hemochromatosis. Liver iron content and serum iron levels were not correlated. No differences in hepatic iron content were observed among patients with a sustained response to IFN (seven patients), short-term responders (seven patients), or nonresponders (14 patients). CONCLUSIONS: Ten percent of patients with chronic hepatitis C have elevated hepatic iron content. These patients cannot be identified using serum markers of iron status. The relationship between liver iron and response to IFN treatment requires further prospective investigations.

[Ion transport in the colon]. / Gli scambi ionici del colon.

The large bowel daily absorbs passively 1500 ml of water down an osmotic gradient created by active electrolyte transports. The system is sustained by the enzyme Na(+)-K+ ATPase, the so called sodium-pump, present on the basolateral membrane of colonocytes. Some pathologic conditions may increase the amount of intraluminal water by inhibiting fluid absorbtion or enhancing fluid secretion. Diarrhoea represents the clinical counterpart of these alterations. Three forms of diarrhoea can be recognized on the basis of pathophysiological alterations. Diarrhoea is due to reduced ionic absorbtion, increased secretion or increased endoluminal osmolality. The drugs used to induce bowel actions or gut lavage increase also intraluminal water content by modifying transmural ionic transports. Laxatives or purges act by increasing either water secretion on endoluminal osmolality and therefore may produce systemic idro-electrolyte imbalance. To avoid this inconvenient an isosmotic electrolyte balanced polyethylene glicol solution (PEG-ELS) has been achieved. In addition orally administred PEG-ELS solution cleans the colon during its intestinal transit without producing relevant transmural water-ionic movements. Aim of this article was to describe the normal ionic transport, and its alterations in pathologic and pharmacologic conditions. Details on PEG-ELS were also given. This solution provides for an effective colon preparation for endoscopic or surgical procedures and resulted to be safe for patients with delicate fluid-electrolyte balance.