Molecular characterization of chronic liver disease dynamics: from liver fibrosis to acute-on-chronic liver failure

BACKGROUND: The molecular mechanisms driving the progression from early chronic liver disease (eCLD) to cirrhosis and, finally, acute-on-chronic liver failure (ACLF) are largely unknown. Thus, the aim of this work is to develop a network-based approach to investigate molecular pathways driving progression from eCLD to ACLF. We created 9 liver-specific biological networks capturing key pathophysiological processes potentially related to CLD. We used these networks as framework to perform gene set enrichment analyses(GSEA) and create dynamic profiles of disease progression. RESULTS: Principal component analyses revealed that samples clustered according to the disease stage. GSEA analyses of the defined processes showed an up-regulation of inflammation, fibrosis and apoptosis networks throughout disease progression. Interestingly, we did not find significant gene expression differences between CC and DC, while ACLF showed acute expression changes in all the defined liver-related networks. The analyses of disease progression patterns identified ascending and descending expression profiles associated to ACLF onset. Functional analyses showed that ascending profiles were associated to inflammation, fibrosis, apoptosis, senescence and carcinogenesis networks, while descending profiles were mainly related to oxidative stress and genetic factors. We confirmed by qPCR the up-regulation of 4 genes of the ascending profile CXCL-6, KRT-18, SPINK-1, and ITGA2, and validated our findings on an independent patient’s cohort. CONCLUSION: ACLF is characterized by a specific hepatic gene expression pattern related to inflammation, fibrosis, apoptosis, senescence and carcinogenesis processes. Moreover, the observed profile is significantly different from that of compensated and decompensated cirrhosis, supporting thus the hypothesis that ACLF should be considered a distinct entity. Transcriptome analysis on liver biopsies from patients at different liver disease stages, including 5 fibrosis(eCLD), 8 compensated cirrhosis, 12 decompensated cirrhosis, 8 ACLF, and 6 control healthy livers was performed.