Background and aims: Liver fibrosis is the main determinant of clinical outcomes in advanced chronic liver disease (ACLD) of any etiology. The introduction of effective etiological therapies has shown that liver fibrosis and even cirrhosis is reversible after eliminating the cause of ACLD. However, not all patients experience fibrosis regression, evidencing that other factors modulate this process. In order to better understand the genetic and molecular mechanisms controlling fibrosis regression we analysed the genetic and tran- scriptomic pathways in ACLD with or without regression of fibrosis using high-throughput technologies. Method: We conducted a case-control pilot study of 60 patients with ACLD of different etiology, 30 with histological and/or clinical evidence of regression (Regressors, Re) and 30 without (Non- regressors, NRe), after a minimum of 24 months of etiological therapy. In all patients we performed genotyping (TaqMan assay) of gene variants associated with liver fibrosis (PNPLA3, TM6SF2, SERPINA1, GCKR, TMC4, HSD17B13). Transcriptomic analysis (RNAseq) was done in 30 frozen paired liver biopsies (before and after therapy) of 15 patients. Differentially Expressed Genes (DEGs) analysis were determined using DESeq2 and selected for FDR <0.05. The enrichment of biological pathways was determined with KEGG. Results: Lack of regression was associated with higher frequency of GCKR-rs1260326 CT-Allele (NRe 63.3% vs Re 36.7%; OR: 0.240, p = 0.020), obesity (63.7% vs. 36.7%, p = 0.041) and higher liver stiffness (33.3 vs. 21.8 kPa, p = 0.032). These three factors remained inde- pendently associated with lower likelihood of ACLD regression on multivariate analysis (Figure). RNAseq data comparing Re vs. NRe in the post-therapy samples disclosed 109 significantly DEGs out of 17, 243 genes. Downregulated DEGs in Re showed significant enrichment for the Hippo signaling pathway ( p < 0.05). Other pathways identified included the PI3K-Akt signaling pathways, ECM-receptor interaction, focal adhesion and relaxin signaling pathways, already known to be involved in liver fibrosis.
