Chronic Hepatitis C Virus (HCV) infection is associated with severe complications such as liver cirrhosis and hepatocellular carcinoma (HCC). For HCV infection, there is a crucial need for novel, preferably non‐invasive tests that could be used to improve the diagnosis and the management programs for patients at high risk of developing severe liver complications, such as cirrhosis and HCC. Classical biochemical markers to follow disease progression show limited potential mainly for invasiveness or little specificity and sensitivity, especially for HCC. The goal of this work was to discover useful biomarkers of disease progression in the setting of chronic HCV infection. In the first part, a Genome Wide Association Study was carried out to study the genetic variability influencing the natural history of HCV infection. A cohort of patients was genotyped and disease stage was evaluated through a liver biopsy before any antiviral treatment. Although no hits reached a genome-wide significance level, candidate regions showing suggestive association were identified. In particular, the gene region containing the GADD45G gene resulted of particular interest, given its role in cell biology. Conversely, the analysis of covariates revealed that they had a profound impact on the progression of the liver disease. Indeed, the age at infection had a marked effect on fibrosis progression (p < 2E‐16), suggesting that this is the major explanatory variable in our cohort. Male gender (p < 0.05) and HCV genotype 3 (p < 0.01) were also associated to faster fibrosis progression. The second part of this work focused on the use of circulating microRNA as blood-based biomarker of disease status. We investigated whether specific serum miRNA signatures may be detected in the serum of patients with chronic HCV infection at different stages of liver disease. Individual sera from healthy controls, patients with chronic hepatitis, liver cirrhosis or HCC were tested by high‐throughput qPCR to profile the expression of the whole miRNome. A solid normalization strategy was applied to reduce variability, and 22 miRNAs were considered differentially represented among the four classes (p<0.05 after multiple testing correction) The levels of miR‐122 and miR‐885‐5p specifically and consistently increased in patients with HCV infection compared to healthy controls or patients with Cronh’s disease (p<0.001). miR‐122 concentration changed significantly among groups with different alanine aminotransferase (ALT) activity (p<0.001), showing a positive trend. In summary, serum levels of miR‐122 and miR‐885‐5p were significantly elevated in patients with HCV‐associated liver pathologies. Our data show the potential use of serum miRNA as novel biomarker in the setting of chronic HCV infection.

(2011). Single Nucleotide Polymorphisms and circulating microRNAs for monitoring HCV disease progression: an integrated approach. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2011).

Single Nucleotide Polymorphisms and circulating microRNAs for monitoring HCV disease progression: an integrated approach

MARABITA, FRANCESCO
2011

Abstract

Chronic Hepatitis C Virus (HCV) infection is associated with severe complications such as liver cirrhosis and hepatocellular carcinoma (HCC). For HCV infection, there is a crucial need for novel, preferably non‐invasive tests that could be used to improve the diagnosis and the management programs for patients at high risk of developing severe liver complications, such as cirrhosis and HCC. Classical biochemical markers to follow disease progression show limited potential mainly for invasiveness or little specificity and sensitivity, especially for HCC. The goal of this work was to discover useful biomarkers of disease progression in the setting of chronic HCV infection. In the first part, a Genome Wide Association Study was carried out to study the genetic variability influencing the natural history of HCV infection. A cohort of patients was genotyped and disease stage was evaluated through a liver biopsy before any antiviral treatment. Although no hits reached a genome-wide significance level, candidate regions showing suggestive association were identified. In particular, the gene region containing the GADD45G gene resulted of particular interest, given its role in cell biology. Conversely, the analysis of covariates revealed that they had a profound impact on the progression of the liver disease. Indeed, the age at infection had a marked effect on fibrosis progression (p < 2E‐16), suggesting that this is the major explanatory variable in our cohort. Male gender (p < 0.05) and HCV genotype 3 (p < 0.01) were also associated to faster fibrosis progression. The second part of this work focused on the use of circulating microRNA as blood-based biomarker of disease status. We investigated whether specific serum miRNA signatures may be detected in the serum of patients with chronic HCV infection at different stages of liver disease. Individual sera from healthy controls, patients with chronic hepatitis, liver cirrhosis or HCC were tested by high‐throughput qPCR to profile the expression of the whole miRNome. A solid normalization strategy was applied to reduce variability, and 22 miRNAs were considered differentially represented among the four classes (p<0.05 after multiple testing correction) The levels of miR‐122 and miR‐885‐5p specifically and consistently increased in patients with HCV infection compared to healthy controls or patients with Cronh’s disease (p<0.001). miR‐122 concentration changed significantly among groups with different alanine aminotransferase (ALT) activity (p<0.001), showing a positive trend. In summary, serum levels of miR‐122 and miR‐885‐5p were significantly elevated in patients with HCV‐associated liver pathologies. Our data show the potential use of serum miRNA as novel biomarker in the setting of chronic HCV infection.
ABRIGNANI, SERGIO
HCV infection, genome-wide association study, liver fibrosis progression, circulating microRNA, miR-122, miR-885-5p, liver cirrhosis, hepatocellular carcinoma
MED/12 - GASTROENTEROLOGIA
English
29-mar-2011
Scuola di Dottorato in Medicina Traslazionale e Molecolare
MEDICINA TRASLAZIONALE E MOLECOLARE (DIMET) - 45R
23
2009/2010
open
(2011). Single Nucleotide Polymorphisms and circulating microRNAs for monitoring HCV disease progression: an integrated approach. (Tesi di dottorato, Università degli Studi di Milano-Bicocca, 2011).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/29993
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