Unique early gene expression patterns in human adult-to-adult living donor liver grafts compared to deceased donor grafts

Abstract

Because of inherent differences between deceased donor (DD) and living donor (LD) liver grafts, we hypothesize that the molecular signatures will be unique, correlating with specific biologic pathways and clinical patterns. Microarray profiles of 63 biopsies in 13 DD and 8 LD liver grafts done at serial time points (procurement, backbench and postreperfusion)were compared between groups using class comparisons, network and biological function analyses. Specific genes were validated by quantitative PCR and immunopathology. Clinical findings were also compared. Following reperfusion, 579 genes in DD grafts and 1324 genes in LDs were differentially expressed (p < 0.005). Many upregulated LD genes were related to regeneration, biosynthesis and cell cycle, and a large number of downregulated genes were linked to hepatic metabolism and energy pathways correlating with posttransplant clinical laboratory findings. There was significant upregulation of inflammatory/immune genes in both DD and LD, each with a distinct pattern. Gene expression patterns of select genes associated with inflammation and regeneration in LD and DD grafts correlated with protein expression. Unique patterns of early gene expression are seen in LD and DD liver grafts, correlating with protein expression and clinical results, demonstrating distinct inflammatory profiles and significant downregulation of metabolic pathways in LD grafts.

Conflict of interest statement

Financial disclosures: The authors have no conflict of interest and no financial disclosures

Figures

Figure 1

A. Diagram of number of differentially expressed genes in each class comparison. The numbers of differentially expressed genes between groups are illustrated in the small boxes connecting the larger shaded boxes (at p-value 0.005). B. Venn diagram of overlap of differentially expressed genes in LD and DD POST reperfusion, compared to PRE transplantation for each graft type.

Figure 2

Figure 2A–C. Immunoperoxidase analysis of gene expression in liver biopsies collected from the donor liver (PRE) and post-reperfusion (POST), showing representative data from 4 samples/group and comparing events using LD and DD liver tissues. Negligible staining for SOCS3, IL1RL1, or IL-8 was seen in the PRE biopsies. (Paraffin sections, hematoxylin counterstain, original magnifications ×250). 2A. Post-reperfusion, SOCS3 expression was upregulated in both LD and DD biopsies with staining of hepatocytes, bile ducts and inflammatory cells 2B. IL1RL1 demonstrates negligible expression in PRE LD biopsies but with upregulation by hepatocytes in post-reperfusion biopsies of LD tissues. There was minimal staining in DD livers, either PRE or POST. 2C. IL-8 was upregulated primarily in post-reperfusion biopsies from DD livers, with minimal LD expression. IL-8 staining was detected in hepatocytes and also in conjunction with infiltrating polymorphonuclear neutrophils.

Figure 3

A. Bilirubin serum levels in LD and DD liver transplant recipients in the perioperative period and the first month after transplant. POD = post-operative day. B. Internationalized Ratios in recipients of a LD liver transplants (LDLT) and DD liver transplants (DD-OLT) in the first month after transplant.