Metabolic Impact of HCV Clearance Examined by Urine Metabonomics in Patients with Severe Liver Fibrosis

Background: Hepatitis C virus (HCV) infection induces a long-term inflammatory response and oxidative-stress in the liver microenvironment, leading to hepatic fibrosis and metabolic alterations. Direct-acting-antiviral-agents (DAAs) induce HCV-clearance, but liver dyshomeostasis is not restored. Understanding the impact of viral-eradication on the liver metabolic activities could allow the optimization of patient’s metabolic care. The present prospective longitudinal study aims to characterize the urinary metabolic profile of HCV-induced severe liver fibrosis and the metabolic changes induced by DAAs and HCV-clearance by Nuclear-Magnetic-Resonance-(NMR)-based-metabolomics. Methods: The urinary metabolic profile of 23 HCV males with severe liver fibrosis and 20 age-matched healthy-controls was analyzed by NMR-based-metabolomics before starting DAAs, at the end-of-therapy, after one and three months of follow-up. Finding: The urinary metabolic profile of patients with severe liver fibrosis was characterized by higher levels of four metabolites related to oxidative-stress (pseudouridine, hypoxanthine, methyl-guanidine, dimethylamine) and two amino-acids (glutamine, tyrosine) compared to healthy-controls. N-methyl-nicotinamide, a catabolic intermediate of nicotinamide-adenine-dinucleotide, and 3-hydroxy-3-methylbutyric-acid, an intermediate of leucine-catabolism, returned to control levels with viral eradication. Finally, 3-hydroxyisobutyrate and 2,3-dihydroxy-2-methyl-butyrate, intermediates of valine-catabolism, increased temporarily during therapy, resulting as potential biomarkers of DAAs systemic effects. Interpretation: The identified metabolic profiles suggest that oxidative-stress persists despite HCV-eradication in the context of severe liver fibrosis, therefore the potential benefit of an antioxidant treatment after HCV-cure could be evaluated by further studies. HCV-clearance permanently restores leucine-catabolism, suggesting an improvement of skeletal muscle protein synthesis. DAA-administration temporarily modifies valine-catabolism, therefore, in case of amino-acid-supplementation, such modifications should be considered. Funding Statement: Sapienza University of Rome (Research Project 2017). Declaration of Interests: All Authors have nothing to disclose regarding conflict of interest with respect to this manuscript. Ethics Approval Statement: The study protocol conformed to the ethical guidelines of the 1975 Declaration of Helsinki and it was approved by the Institutional Review Board. All patients provided their written informed consent to participate in the study.