Expression of fibrosis-related genes in liver allografts: Association with histology and long-term outcome after pediatric liver transplantation

Background Unexplained graft fibrosis and inflammation are common after pediatric liver transplantation (LT). Objective We investigated the graft expression of fibrogenic genes and correlated the findings with transplant histopathology and outcome. Methods Liver biopsies from 29 recipients were obtained at a median of 13.1 (IQR: 5.0-18.4) years after pediatric LT. Control samples were from six liver-healthy subjects. Hepatic expression of 40 fibrosis-related genes was correlated to histological findings: normal histology, fibrosis with no inflammation, and fibrosis with inflammation. Liver function was evaluated after a subsequent follow-up of 9.0 years (IQR: 8.0-9.4). Results Patients with fibrosis and no inflammation had significantly increased gene expression of profibrotic TGF-beta 3 (1.17 vs. 1.02 p = .005), CTGF (1.64 vs. 0.66 p = .014), PDGF-alpha (1.79 vs. 0.98 p = .049), PDGF -beta (0.99 vs. 0.76 p = .006), integrin-subunit-beta 1 (1.19 vs. 1.02 p = .045), alpha-SMA (1.12 vs. 0.58 p = .013), type I collagen (0.82 vs. 0.53 p = .005) and antifibrotic decorin (1.15 vs. 0.99 p = .045) compared to patients with normal histology. mRNA expression of VEGF A (0.84 vs. 1.06 p = .049) was lower. Only a few of the studied genes were upregulated in patients with both fibrosis and inflammation. The gene expression levels showed no association with later graft outcome. Conclusions Altered hepatic expression of fibrosis-related genes is associated with graft fibrosis without concurrent inflammation.