Background & aims: Although extensive experimental evidence on the process of liver regeneration exists, in humans, validation is largely missing. However, liver regeneration is critically affected by underlying liver disease. Within this project, we aimed to systematically assess early transcriptional changes during liver regeneration in humans and further assess how these processes differ in people with dysfunctional liver regeneration.
Methods: Blood samples of 154 patients and intraoperative tissue samples of 46 patients undergoing liver resection were collected and classified with regard to dysfunctional postoperative liver regeneration. Of those, a matched cohort of 21 patients were used for RNA sequencing. Samples were assessed for circulating cytokines, gene expression dynamics, intrahepatic neutrophil accumulation, and spatial transcriptomics.
Results: Individuals with dysfunctional liver regeneration demonstrated an aggravated transcriptional inflammatory response with higher intracellular adhesion molecule-1 induction. Increased induction of this critical leukocyte adhesion molecule was associated with increased intrahepatic neutrophil accumulation and activation upon induction of liver regeneration in individuals with dysfunctional liver regeneration. Comparing baseline gene expression profiles in individuals with and without dysfunctional liver regeneration, we found that dual-specificity phosphatase 4 (DUSP4) expression, a known critical regulator of intracellular adhesion molecule-1 expression in endothelial cells, was markedly reduced in patients with dysfunctional liver regeneration. Mimicking clinical risk factors for dysfunctional liver regeneration, we found liver sinusoidal endothelial cells of two liver disease models to have significantly reduced baseline levels of DUSP4.
Conclusions: Exploring the landscape of early transcriptional changes of human liver regeneration, we observed that people with dysfunctional regeneration experience overwhelming intrahepatic inflammation. Subclinical liver disease might account for DUSP4 reduction in liver sinusoidal endothelial cells, which ultimately primes the liver for an aggravated inflammatory response.
Impact and implications: Using a unique human biorepository, focused on liver regeneration (LR), we explored the landscape of circulating and tissue-level alterations associated with both functional and dysfunctional LR. In contrast to experimental animal models, people with dysfunctional LR demonstrated an aggravated transcriptional inflammatory response, higher intracellular adhesion molecule-1 (ICAM-1) induction, intrahepatic neutrophil accumulation and activation upon induction of LR. Although inflammatory responses appear rapidly after liver resection, people with dysfunctional LR have exaggerated inflammatory responses that appear to be related to decreased levels of LSEC DUSP4, challenging existing concepts of post-resectional LR.
Keywords: ALT, alanine aminotransferase; AST, aspartate aminotransferase; CASH, chemotherapy associated steatohepatitis; DLR, dysfunctional LR; DUSP-4; DUSP4, dual-specificity phosphatase 4; FDR, false discovery rate; FLR, functional LR; FPKM, fragments per kilobase of transcript per million mapped reads; Human; ICAM-1, intracellular adhesion molecule-1; IPA, Ingenuity Pathway Analysis; IVCL, inferior vena cava ligation; Inflammation; LPS, lipopolysaccharide; LR, liver regeneration; LSEC, liver sinusoidal endothelial cell; Liver regeneration; MFI, mean fluorescence intensity; MPO, myeloperoxidase; NASH, non-alcoholic steatohepatitis; Neutrophils; PCA, principal component analysis; POD1, 1 day after liver resection; POD5, 5 days after liver resection; STRING, Search Tool for the Retrieval of Interacting Genes/Proteins; TMM, trimmed mean of M values; TNF, tumour necrosis factor; logCPM, log counts per million; pTPM, protein-coding transcripts per million.
© 2023 The Author(s).