Proteomic analysis for developing new biomarkers of hepatocellular carcinoma

AIM: To identify new markers of hepatocellular carcinoma (HCC) using a proteomic analysis. METHODS: Patients with liver cirrhosis of the three most frequent etiologies: hepatitis C virus, hepatitis B virus and alcoholic liver disease, were included in the study. The samples were analysed by 2D-electrophoresis in order to determine the differential protein expression. The proteins were separated according to the charge in immobilized pH 3-10 gradient strips and then by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Proteins of interest were excised, digested with trypsin and the resulting peptides were separated and identified. RESULTS: Three differentially expressed apolipoproteins (Apo) were identified based on the protein profile using proteomic techniques: Apo-A1, Apo-A4 and Apo-E. Apo-A4 levels were significantly lower in HCC than in non-HCC patients regardless of etiology (P < 0.01). Multivariate logistic regression showed that Apo-A4 and Apo-A1 were the only independent factors related to HCC diagnosis (P < 0.05). The receiver operating characteristic (ROC) curve including both Apo-A4 and Apo-A1 showed an area under the ROC of 0.944 (P < 0.001), a sensitivity of 0.89 and a specificity of 0.81 for diagnosis of HCC. CONCLUSION: Apo-A4 and Apo-A1 may be used clinically as biomarkers of HCC with a high sensibility and specificity. These findings may provide additional insights into the mechanism of HCC development and progression.

Diagnosis and management of bacterial infections in decompensated cirrhosis

Bacterial infections are one of the most frequent complications in cirrhosis and result in high mortality rates.Patients with cirrhosis have altered and impaired immunity,which favours bacterial translocation.Episodes of infections are more frequent in patients with decompensated cirrhosis than those with compensated liver disease.The most common and life-threatening infection in cirrhosis is spontaneous bacterial peritonitis followed by urinary tract infections,pneumonia,endocarditis and skin and soft-tissue infections.Patients with decompensated cirrhosis have increased risk of developing sepsis,multiple organ failure and death.Risk factors associated with the development of infections are severe liver failure,variceal bleeding,low ascitic protein level and prior episodes of spontaneous bacterial peritonitis (SBP).The prognosis of these patients is closely related to a prompt and accurate diagnosis.An appropriate treatment decreases the mortality rates.Preventive strategies are the mainstay of the management of these patients.Empirical antibiotics should be started immediately following the diagnosis of SBP and the first-line antibiotic treatment is third-generation cephalosporins.However,the efficacy of currently recommended empirical antibiotic therapy is very low in nosocomial infections including SBP,compared to community-acquired episodes.This may be associated with the emergence of infections caused by Enterococcus faecium and extended-spectrum β-lactamaseproducing Enterobacteriaceae,which are resistant to the first line antimicrobial agents used for treatment.The emergence of resistant bacteria,underlines the need to restrict the use of prophylactic antibiotics to patients with the greatest risk of infections.Nosocomial infections should be treated with wide spectrum antibiotics.Further studies of early diagnosis,prevention and treatment are needed to improve the outcomes in patients with decompensated cirrhosis.

Strategies to improve outcome of patients with hepatocellular carcinoma receiving a liver transplantation

The current management therapies for hepatocellular carcinoma(HCC) patients are discussed in this review. Despite the development of new therapies, HCC remains a 'difficult to treat' cancer because HCC typically occurs in advanced liver disease or hepatic cirrhosis. The progression of multistep and multicentric HCC hampers the prevention of the recurrence of HCC. Many HCC patients are treated with surgical resection and radiofrequency ablation(RFA), although these modalities should be considered in only selected cases with a certain HCC number and size. Although there is a shortage of grafts, liver transplantation has the highest survival rates for HCC. Several modalities are salvage treatments; however, intensive care in combination with other modalities or in combination with surgical resection or RFA might offer a better prognosis. Sorafenib is useful for patients with advanced HCC. In the near future, HCC treatment will include stronger molecular targeted drugs, which will have greater potency and fewer adverse events. Further studies will be ongoing.

Nitric oxide and cancer

Nitric oxide (NO) is a lipophilic,highly diffusible and short-lived physiological messenger which regulates a variety of important physiological responses including va sodilation,respiration,cell migration,immune resp onse and apoptosis.NO is synthesized by three differ entially gene-encoded NO synthase (NOS) in mammals: neuronal NOS (nNOS or NOS-1),inducible NOS (iNOS or NOS-2) and endothelial NOS (eNOS or NOS-3).All isof or ms of NOS catalyze the reaction of L-arginine,NA DPH and oxygen to NO,L-citrulline and NADP.NO may exert its cellular action by cGMP-dependent as well as by cGMP-independent pathways including postranslational modifications in cysteine (S-nitrosylation or S-nit rosation) and tyrosine (nitration) residues,mixed disulf ide formation (S-nitrosoglutathione or GSNO) or prom ot ing further oxidation protein stages which have been related to altered protein function and gene transcription,genotoxic lesions,alteration of cell-cycle check points,apoptosis and DNA repair.NO sensitizes tumor cells to chemotherapeutic compounds.The expression of NOS-2 and NOS-3 has been found to be increased ina variety of human cancers.The multiple actions of NO in the tumor environment is related to heterogeneous cell responses with particular attention in the regulation of the stress response mediated by the hypoxia inducible factor-1 and p53 generally leading to growth arrest,apoptosis or adaptation.

Strategies to reduce hepatitis C virus recurrence after liver transplantation

Hepatitis C virus (HCV) is a major health problem that leads to chronic hepatitis, cirrhosis and hepatocellular carcinoma, being the most frequent indication for liver transplantation in several countries. Unfortunately, HCV re-infects the liver graft almost invariably following reperfusion, with an accelerated history of recurrence, leading to 10%-30% of patients progressing to cirrhosis within 5 years of transplantation. In this sense, some groups have even advocated for not retransplanting this patients, as lower patient and graftoutcomes have been reported. However, the management of HCV recurrence is being optimized and several strategies to reduce post-transplant recurrence could improve outcomes, decrease the rate of re-transplantation and optimize the use of available grafts. Three moments may be the focus of potential actions in order to decrease the impact of viral recurrence: the pretransplant moment, the transplant environment and the post-transplant management. In the pre-transplant setting, it is not well established if reducing the pre transplant viral load affects the risk for HCV progression after transplant. Obviously, antiviral treatment can render the patient HCV RNA negative post transplant but the long-term benefit has not yet been fully established to justify the cost and clinical risk. In the transplant moment, factors as donor age, cold ischemia time, graft steatosis and ischemia/reperfusion injury may lead to a higher and more aggressive viral recurrence. After the transplant, discussion about immunosuppression and the moment to start the treatment (prophylactic, pre-emptive or once-confirmed) together with new antiviral drugs are of interest. This review aims to help clinicians have a global overview of posttransplant HCV recurrence and strategies to reduce its impact on our patients.