L-FABP as a Potential Biomolecular Marker of Liver Graft Injury

Background: In recent years, indications for liver transplantation have expanded, while the age of transplant recipients has significantly increased due to improvements in perioperative management. As clinical manifestations of posttransplant complications vary and are often nonspecific, the identification of appropriate biomarkers is important for the assessment of graft quality and early recognition of potential complications following liver transplantation. Liver-type FABP (L-FABP) is a small cytoplasmic protein found abundantly in hepatocytes and is involved in the intracellular transport of long-chain fatty acids. Elevated serum levels have been detected in acute and chronic liver failure, kidney failure, and some malignancies. Materials and Methods: We conducted a prospective, single-center study from July 2023 to January 2025, including 29 adult patients who underwent deceased-donor transplantation. Three patients were excluded due to inadequate sample withdrawals. Serum L-FABP was measured preoperatively and on postoperative days 1, 3, 5, 7, and 14. Clinical, surgical, and biochemical data were collected and analyzed using non-parametric statistical tests. Results: L-FABP levels were significantly higher on POD 7 in recipients of grafts from donors ≥ 65 years (p = 0.035), with no corresponding changes in standard liver function markers. While no significant differences in L-FABP levels were found between patients with and without infectious biliary or vascular complications (all p > 0.05), we proved a strong negative correlation between intraoperative blood transfusion volume and L-FABP levels on POD 5 (ρ = -0.677, p < 0.001) and POD 7 (ρ = -0.455, p = 0.025). Conclusions: Our findings suggest that L-FABP holds promise as a biomarker for the early detection of subclinical hepatic graft cellular injury, which is not detected by means of conventional biomarkers for liver function.