Advancement in the development of models for hepatitis C research. J Biomed Biotechnol. 2012;2012:346761. [PMID: 22701302 PMCID: PMC3369559 DOI: 10.1155/2012/346761]

Animal models as a tool in hepatocellular carcinoma research: A Review

Cancer is the first cause of death in developed countries and the second in developing countries. Concerning the most frequent worldwide-diagnosed cancer, primary liver cancer represents approximately 4% of all new cancer cases diagnosed globally. However, among primary liver cancer, hepatocellular carcinoma is by far the most common histological subtype. Notwithstanding the health promotion and disease prevention campaigns, more than half a million new hepatocellular carcinoma cases are reported yearly, being estimated to growth continuously until 2020. Taking this scenario under consideration and the fact that some aspects concerning hepatocellular carcinoma evolution and metastasize process are still unknown, animal models assume a crucial role to understand this disease. The animal models have also provided the opportunity to screen new therapeutic strategies. The present review was supported on research and review papers aiming the complexity and often neglected chemically induced animal models in hepatocarcinogenesis research. Despite the ongoing debate, chemically induced animal models, namely, mice and rat, can provide unique valuable information on the biotransformation mechanisms against xenobiotics and apprehend the deleterious effects on DNA and cell proteins leading to carcinogenic development. In addition, taking under consideration that no model achieves all hepatocellular carcinoma research purposes, criteria to define the " ideal" animal model, depending on the researchers' approach, are also discussed in this review.

Molecular and immunological tools for the evaluation of the cellular immune response in the neotropical monkey Saimiri sciureus, a non-human primate model for malaria research

Background

The neotropical, non-human primates (NHP) of the genus Saimiri and Aotus are recommended by the World Health Organization as experimental models for the study of human malaria because these animals can be infected with the same Plasmodium that cause malaria in humans. However, one limitation is the lack of immunological tools to assess the immune response in these models. The present study focuses on the development and comparative use of molecular and immunological methods to evaluate the cellular immune response in Saimiri sciureus.

Methods

Blood samples were obtained from nineteen uninfected Saimiri. Peripheral blood mononuclear cells (PBMC) from these animals and splenocytes from one splenectomized animal were cultured for 6, 12, 18, 24, 48, 72 and 96 hrs in the presence of phorbol-12-myristate-13-acetate and ionomycin. The cytokine levels in the supernatant were detected using human and NHP cytometric bead array Th1/Th2 cytokine kits, the Bio-Plex Pro Human Cytokine Th1/Th2 Assay, enzyme-linked immunosorbent assay, enzyme-linked immunospot assays and intracellular cytokine secretion assays. Cytokine gene expression was examined through TaqMan® Gene Expression Real-Time PCR using predesigned human gene-specific primers and probes or primers and probes designed based on published S. sciureus cytokine sequences.

Results

The use of five assays based on monoclonal antibodies specific for human cytokines facilitated the detection of IL-2, IL-4 and/or IFN-γ. TaqMan array plates facilitated the detection of 12 of the 28 cytokines assayed. However, only seven cytokines (IL-1A, IL-2, IL-10, IL-12B, IL-17, IFN-β, and TNF) presented relative expression levels of at least 70% of the gene expression observed in human PBMC. The use of primers and probes specific for S. sciureus cytokines facilitated the detection of transcripts that showed relative expression below the threshold of 70%. The most efficient evaluation of cytokine gene expression, in PBMC and splenocytes, was observed after 6–12 hrs of culture, except for LTA in PBMC, whose expression was best analysed after 24 hrs of culture.

Conclusions

Real-time PCR facilitates the analysis of a large number of cytokines altered during malaria infection, and this technique is considered the best tool for the evaluation of the cellular immune response in S. sciureus.

The reproducibility of biomedical research: Sleepers awake!

There is increasing concern about the reliability of biomedical research, with recent articles suggesting that up to 85% of research funding is wasted. This article argues that an important reason for this is the inappropriate use of molecular techniques, particularly in the field of RNA biomarkers, coupled with a tendency to exaggerate the importance of research findings.

Pegylated interferon α-2a plus ribavirin for decompensated hepatitis C virus-related cirrhosis: relationship between efficacy and cumulative dose

BACKGROUND & AIMS

A combination of pegylated interferon alpha-2a (Peg-IFNα-2a) and ribavirin (RBV) achieves a sustained virological response (SVR) in 40-50% of patients infected with genotype 1 hepatitis C virus (HCV), but efficacy rates are significantly lower in patients with decompensated HCV-induced cirrhosis. The efficacy and tolerability of Peg-IFNα-2a and RBV, the cumulative dose effect, time to achieve planned cumulative dose and role of HCV phenotype on treatment response were determined in patients with decompensated HCV-induced cirrhosis.

METHODS

In this case-controlled study, 257 patients with decompensated HCV-induced cirrhosis were enrolled, including patients treated with partial splenic embolization for leukopaenia. Of patients with sufficient blood cell counts, 130 patients opted for antiviral therapy (treatment group) consisting of 180 μg/kg Peg-IFNα-2a for 48 weeks with 800-1200 mg/day RBV; the remaining 127 were considered the control group. Primary endpoints were SVR and absence of relapse; the secondary end point was assessment of disease progression.

RESULTS

Sustained virological response was highest and relapse rates were lowest when cumulative doses of Peg-IFNα-2a and RBV were both ≥80% of the prescribed dose. Patients achieving ≥80% of the planned cumulative doses in 48 weeks had a significantly higher SVR compared with patients achieving this in 72 weeks. Patients with HCV genotype 1 had significantly lower SVR compared with patients with HCV genotype 2 (19.7% vs. 42.9%, respectively; P = 0.008). Treatment group patients had a significantly lower rate of SVR-independent liver disease-related mortality.

CONCLUSIONS

Our findings provide additional evidence to support the use of Peg-IFNα-2a and RBV therapy for decompensated HCV-induced cirrhosis.

Scotomas in molecular virology and epidemiology of hepatitis C virus

In the 1970s, scientists learned of a new pathogen causing non-A, non-B hepatitis. Classical approaches were used to isolate and characterize this new pathogen, but it could be transmitted experimentally only to chimpanzees and progress was slow until the pathogen was identified as hepatitis C virus (HCV) in 1989. Since then, research and treatment of HCV have expanded with the development of modern biological medicine: HCV genome organization and polyprotein processing were delineated in 1993; the first three-dimensional structure of HCV nonstructural protein (NS3 serine protease) was revealed in 1996; an infectious clone of HCV complementary DNA was first constructed in 1997; interferon and ribavirin combination therapy was established in 1998 and the therapeutic strategy gradually optimized; the HCV replicon system was produced in 1999; functional HCV pseudotyped viral particles were described in 2003; and recombinant infectious HCV in tissue culture was produced successfully in 2005. Recently, tremendous advances in HCV receptor discovery, understanding the HCV lifecycle, decryption of the HCV genome and proteins, as well as new anti-HCV compounds have been reported. Because HCV is difficult to isolate and culture, researchers have had to avail themselves to the best of modern biomedical technology; some of the major achievements in HCV research have not only advanced the understanding of HCV but also promoted knowledge of virology and cellular physiology. In this review, we summarize the advancements and remaining scotomas in the molecular virology and epidemiology of HCV.

Validation of a solid-phase electrochemical array for genotyping hepatitis C virus

Hepatitis C viral infection is a major cause of progressive liver disease. HCV genotype is one of the most significant baseline predictors of response to HCV antiviral therapy. The objective was to evaluate an HCV genotyping method that targets the 5'-untranslated region (UTR) to detect genotypes/subtypes using the GenMark eSensor® XT-8 system. The HCV amplicon of major genotypes/subtypes from the Roche TaqMan® HCV assay served as a template for the nested PCR followed by a direct analysis on the XT-8 detection system. The assay was validated for limit of detection (LOD), specificity, accuracy and precision. The LOD determined was below 175 IU/ml for all the subtypes except 6ab. The genotypes detected using this assay were in concordance with the LiPA assay. The high performance characteristics (LOD, specificity, intra- and inter-assay precision, and accuracy), make this assay particularly well suited for clinical HCV genotyping in order to guide antiviral therapy.