Involvement of the receptor for advanced glycation end products in liver transplantation

Abstract

Background and aim. Receptor for advanced glycation end products (RAGE) blockade by a soluble form of RAGE (sRAGE) appears to be protective against hepatocellular death and necrosis after I/R injury. Little is known about the role of the hepatic RAGE, its ligands, and the plasma levels of sRAGE in liver transplantation (LT).Material and methods. This was a prospective study on patients (n = 28) undergoing deceased donor LT. RAGE ligands [the N(epsilon)-carboxy-methyl-lysine (CML) adduct and the high-mobility group box 1 (HMGB1) protein] and sRAGE levels were measured in donors at the time of organ procurement, while in recipients they were tested before surgery (baseline), after graft reperfusion, and on day 1 and 7 posttransplantation. Donors and recipients liver biopsies were collected to assess the transcriptional expression of the full-length RAGE and of its truncated isoform, the endogenous secreted RAGE (esRAGE).Results. At baseline, CML levels were higher in LT recipients than in donors (p = 0.02), decreased immediately after graft reperfusion (p < 0.0001) and returned to baseline values on day 7. Baseline HMGB1 levels (3.8 ± 2.3 ng/mL) increased after graft reperfusion (39.9±18 ng/mL, p < 0.0001), and returned to baseline values within day 1, while circulating sRAGE decreased significantly on day 7 (p < 0.0001). The graft esRAGE mRNA expression was inversely associated with bilirubin on day 7 (β = -0.62, p = 0.005).Conclusions. Early on after LT, there is accumulation of CML and a rapid increase of HMGB1 concurrent with a remarkable decline in circulating sRAGE. The RAGE-ligand axis may also be involved in early graft dysfunction.

Keywords

• High-mobility group box 1
• N(epsilon)-carboxy-methyl-lysine
• Liver transplantation
• I/R injury