MSACL 2024 Abstract

INTRODUCTION: Metabolic-Dysfunction Associated Steatotic Liver Disease (MASLD) has become the most prevalent liver disease worldwide, affecting about 30% of the population. Increased liver fibrosis within the MASLD patient population has been shown to be the most important feature associated with higher mortality and likelihood of developing liver-related complications, for which detection and staging liver biopsy remains the clinical reference standard. However, biopsies convey potential for complications and suffer from sampling and reading errors, whereas current non-invasive diagnostics fall short on early detection. Glycosylation of blood proteins, that are mostly synthetized and glycosylated in the liver, may have the potential to address this unmet clinical need, as alterations to the blood protein N-glycome have been shown as hallmarks of liver pathologies.

OBJECTIVES: Encouraged by these earlier findings, here we explored total blood protein N-glycosylation of individuals with MASLD and varying degree of fibrosis, with the aim to identify clinically translatable biomarkers allowing for early detection.

METHODS: N-glycosylation of blood proteins was profiled on the released glycan level by a high-throughput matrix-assisted laser-desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry-based method for a total of 75 MASLD patients and 72 healthy controls in two independent cohorts. This platform enabled the unambiguous identification of more than 80 N-glycans including sialic acid linkage-isomers with high glycoform resolution.

RESULTS: A distinctive, globally low α2,3-sialylation (i.e. irrespective of N-glycan antennarity) signature was found in MASLD, which distinguished patients from healthy controls in both cohorts. Upon further stratification based on fibrosis grade, this signature was found to be indicative for MASLD-related fibrosis (F1-F4) , with tri- and tetra-antennary N-glycan α2,3-sialylation displaying the highest discriminative power from healthy controls and F0 patients (AUC=0.90, CI: 0.82-0.97).

CONCLUSION: In conclusion, our data sheds light on a replicated fibrosis-specific blood N-glycosylation in MASLD, which allows the non-invasive detection of fibrosis early-on. The global decrease of α2,3-sialylation, a unique feature on circulatory proteins produced by the fibrotic liver, offers the possibility for developing novel non-invasive diagnostic tests that facilitate early diagnosis, potentially leading to the improvement of patient outcomes and the reduction of liver-related morbidity and mortality.