Gene Transduction of an Active Mutant of Akt Exerts Cytoprotection and Reduces Graft Injury After Liver Transplantation

Akt is expected to be an effective target for the treatment of ischemia-reperfusion injury (I/R) due to its anti-apoptotic properties and its ability to activate the endothelial nitric oxide synthase (eNOS) enzyme. Therefore, this study was aimed to determine the efficacy of an active mutant of Akt (myr-Akt) to decrease I/R injury in a model of orthotopic liver transplantation in pigs. In addition, we analyzed the contribution of nitric oxide in the Akt-mediated effects by using an eNOS mutant (S1179DeNOS) that mimics the phosphorylation promoted by Akt in the eNOS sequence. Donors were treated with adenoviruses codifying for myr-Akt, S1179DeNOS or beta-galactosidase 24 h before liver harvesting. Then, liver grafts were orthotopically transplanted into their corresponding recipients. Levels of transaminases and lactate dehydrogenase (LDH) increased in all recipients after 24 h of transplant. However, transaminases and LDH levels were significantly lower in the myr-Akt group compared with vehicle. The percentage of apoptotic cells and the amount of activated-caspase 3 protein were also markedly reduced in myr-Akt-treated grafts after 4 days of liver transplant compared with vehicle and S1179DeNOS groups. In conclusion, myr-Akt gene therapy effectively exerts cytoprotection against hepatic I/R injury regardless of the Akt-dependent eNOS activation.     

In-111 octreotide scan in a case of a neuroendocrine tumor of unknown origin

Major neuroendocrine tumors contain many somatostatin receptors. This feature allows for the localization of primary tumors and tumor metastases by scintigraphy with the radiolabeled somatostatin analog octreotide. We describe a patient with nonspecific clinical data and ultrasonography and CT that showed an isolated focal lesion in the liver. In-111 octreotide scintigraphy was essential in establishing the diagnosis of liver metastasis from a neuroendocrine tumor confirmed by pathologic findings. Because clinical symptoms recurred, ultrasonography and CT were performed a few months after surgery. Both were negative. However, In-111 octreotide scintigraphy suggested multiple bone metastases and established the diagnosis of bone metastases from a neuroendocrine tumor, which was confirmed by Tc-99m MDP bone scans and MRI.     

Bacterial infections in cirrhosis: epidemiological changes with invasive procedures and norfloxacin prophylaxis.

The extensive use of invasive procedures and of long-term norfloxacin prophylaxis in the management of cirrhotic patients may have influenced the epidemiology of bacterial infections in cirrhosis. We conducted a prospective evaluation of all bacterial infections diagnosed in patients with cirrhosis in a Liver Unit between April 1998 and April 2000. A total of 405 patients presented 572 bacterial infections in 507 admissions. Spontaneous bacterial peritonitis was the most frequent infection (138 cases). Gram-positive cocci were responsible for 53% of total bacterial infections in the study, being the main bacteria isolated in nosocomial infections (59%). Patients requiring treatment in an intensive care unit and those submitted to invasive procedures presented a higher rate of infections caused by gram-positive cocci (77% vs. 48%, P <.001 and 58% vs. 40%, P <.02, respectively). Fifty percent of culture-positive spontaneous bacterial peritonitis in patients on long-term norfloxacin administration (n = 93) and 16% in patients not receiving this therapy (n = 414) were caused by quinolone-resistant gram-negative bacilli, P =.01. The rate of culture-positive spontaneous bacterial peritonitis caused by trimethoprim-sulfamethoxazole-resistant gram-negative bacilli was also very high in patients on long-term norfloxacin administration (44% vs. 18%, P =.09). In conclusion, infections caused by gram-positive cocci have markedly increased in cirrhosis. This phenomenon may be related to the current high degree of instrumentation of cirrhotic patients. Quinolone-resistant spontaneous bacterial peritonitis constitutes an emergent problem in patients on long-term norfloxacin prophylaxis, with trimethoprim-sulfamethoxazole not being a valid alternative.     

Hepatitis C virus kinetics during and immediately after liver transplantation

The study of hepatitis C virus (HCV) kinetics after liver transplantation (LT) might be important to design strategies to prevent HCV infection of the graft. We analyzed HCV kinetics during and immediately after LT in 20 consecutive patients undergoing LT for HCV-related cirrhosis. HCV RNA was quantified in blood samples obtained at regular intervals before, during, and after transplantation. HCV-RNA concentrations decreased in 18 of 20 patients during the anhepatic phase (mean decay slope -0.92, mean HCV elimination half-life 2.2 hours). We found a significant correlation between the HCV viral load decay and the blood loss during the anhepatic phase, indicating that the observed HCV clearance rates are maximum estimates. In fact, in 1 patient with an unusually long anhepatic phase of 20 hours and with minimum blood loss, the HCV elimination half-life was 10.3 hours. Eight to 24 hours after graft reperfusion a sharp decrease in HCV viral load occurred in 19 patients (mean decay slope -0.34, mean HCV elimination half-life 3.44 hours). HCV RNA became undetectable in only 1 patient. During the following days, HCV-RNA concentrations increased rapidly in 10 patients (mean HCV doubling time 13.8 hours), remained at similar levels in 4, and continued to decrease in 6. The only variable associated with a second-phase viral load decay was the absence of corticosteroids as part of the immunosuppressive regimen. In conclusion, a sharp decrease in HCV viral load occurs during the anhepatic phase and immediately after graft reperfusion, most likely owing to a lack of virion production and hepatic viral clearance. HCV infection of the graft, however, is an extremely dynamic process and viral replication begins a few hours after LT.     

Hepatopulmonary syndrome in candidates for liver transplantation

BACKGROUND: Hepatopulmonary syndrome (HPS) has been defined as a clinical triad, including chronic liver disease, gas exchange defects (increased alveolar-arterial PO2 difference irrespective of the presence of arterial hypoxemia), and widespread intrapulmonary vascular dilatations. We determined the incidence and the clinical and pulmonary functional characteristics of HPS in candidates for orthotopic liver transplantation (OLT) and tested their predicted accuracy. METHODS: We studied 80 patients with cirrhosis prospectively, and carried out contrast-enhanced (CE) echocardiography and lung function tests, including ventilation-perfusion (V(A)/Q) distributions. RESULTS: Fourteen patients had HPS (incidence, 17.5%). Patients with HPS (49 +/- 12 (+/-SD) years) had more cutaneous spiders, finger clubbing and dyspnea (P < 0.05 each) and a lower diffusing capacity (DLCO, 56 +/- 18% predicted; P < 0.001) than non-HPS patients (n = 66). Mild to moderate V(A)/Q inequalities and increased intrapulmonary shunt were predominant in HPS patients, but oxygen diffusion impairment was observed in those with hypoxemia (n = 8) only. The DLCO showed a considerable area under the receiver operating characteristic curve (0.89). CONCLUSIONS: HPS in cirrhotic patient candidates for OLT shows a high incidence and these patients present with distinctive clinical and functional features compared with non-HPS individuals. The presence of a low DLCO may be of help for the diagnosis of HPS.     

Terlipressin plus albumin infusion: an effective and safe therapy of hepatorenal syndrome

BACKGROUND/AIM: Ornipressin, a vasopressin analog with potent splanchnic vasoconstrictor action, has been shown to reverse hepatorenal syndrome. However, its usefulness in clinical practice is limited by frequent ischemic complications. The aim of this study was to assess the efficacy of terlipressin, an analog of vasopressin with a low profile of side effects, plus albumin in this condition. METHODS: Nine consecutive patients with cirrhosis and hepatorenal syndrome were included in a pilot study of terlipressin (0.5-2 mg/4 h i.v.) therapy associated with iv albumin. RESULTS: Treatment (9 days, range 5-15) was associated with a marked reduction of serum creatinine (3.9+/-0.7 to 1.3+/-0.1 mg/dl, p<0.001, mean+/-SE). Reversal of hepatorenal syndrome (reduction of creatinine below 1.5 mg/dl) was observed in seven of the nine patients. There was a remarkable improvement in circulatory function, with an increase in mean arterial pressure (68+/-2 to 80+/-4 mmHg, p<0.05) and suppression of vasoconstrictor systems activity (plasma renin activity and plasma norepinephrine decreased from 23+/-12 ng/ml x h and 1549+/-373 pg/ml to 3.5+/-2 ng/ml x h and 373+/-98 pg/ml, respectively, p<0.01 for both). No patient developed signs of intestinal, myocardial or distal ischemia. CONCLUSIONS: Terlipressin associated with albumin appears to be a safe and effective treatment of hepatorenal syndrome.     

Macrophage p38 mitogen-activated protein kinase activity regulates invariant natural killer T-cell responses during Borrelia burgdorferi infection

The interaction of macrophages with infectious agents leads to the activation of several signaling cascades, including mitogen-activated protein (MAP) kinases, such as p38. We now demonstrate that p38 MAP kinase-mediated responses are critical components to the immune response to Borrelia burgdorferi. The pharmacological and genetic inhibition of p38 MAP kinase activity during infection with the spirochete results in increased carditis. In transgenic mice that express a dominant negative form of p38 MAP kinase specifically in macrophages, production of the invariant natural killer T (iNKT) cell-attracting chemokine MCP-1 and of the antigen-presenting molecule CD1d are significantly reduced. The expression of the transgene therefore results in the deficient infiltration of iNKT cells, their decreased activation, and a diminished production of interferon γ (IFN-γ), leading to increased bacterial burdens and inflammation. These results show that p38 MAP kinase provides critical checkpoints for the protective immune response to the spirochete during infection of the heart.     

Long-term haemodynamic effects of isosorbide 5-mononitrate in patients with cirrhosis and portal hypertension

Since it is well known that pharmacological tolerance may rapidly occur on continuous administration of organic nitrates, in this study we attempted to investigate whether isosorbide 5-mononitrate (Is-5-Mn), a long-acting vasodilator that decreases portal pressure in acute haemodynamic studies, causes a significant reduction in portal pressure following long-term oral administration. Eleven patients with cirrhosis and portal hypertension were studied prior to and following 3 months of continuous administration of Is-5-Mn, 40 mg b.i.d. The hepatic venous pressure gradient decreased significantly following long-term Is-5-Mn treatment (from 18.6 +/- 3.4 to 17.2 +/- 3.1 mmHg; p less than 0.01). This was associated with a moderate increase in hepatic blood flow. Azygos blood flow and portal blood flow did not change. There were significant decreases in mean arterial pressure (from 89.4 +/- 13.7 to 82.6 +/- 10.8 mmHg; p less than 0.05) and heart rate (from 77 +/- 10 to 73 +/- 10 b.p.m.; p less than 0.05). In contrast, there were no changes in portal pressure or hepatic and systemic haemodynamics in a control group of 17 patients receiving placebo. Repeated nitroglycerin cross-tolerance studies in five patients receiving Is-5-Mn indicated the development of a partial pharmacological tolerance (as shown by blunted haemodynamic response to nitroglycerin after long-term Is-5-Mn administration). This study shows that Is-5-Mn continues to cause a significant decrease in portal pressure during long-term therapy, with only partial pharmacological tolerance to this compound.