Background: Distinguishing bariatric surgical effects on reversing nonalcoholic fatty liver disease (NAFLD) remain unclear. To assess discrepancies in histological response and changes in magnetic resonance imaging-proton density fat fraction (MRI-PDFF) after bariatric surgery.
Methods: This prospective multicenter cohort included 138 NAFLD patients who underwent bariatric surgery and were followed up for 1 year. We obtained paired liver biopsy samples (n = 40), paired proteomic data (n = 23), and sequential MRI-PDFF at 3-, 6-, and 12-month (n = 80, 65, 52, respectively) follow-ups.
Results: At 1 year, a ≥2-point improvement in NAFLD activity score (NAS) was observed in 80.0% of patients; nonalcoholic steatohepatitis (NASH) improved without fibrosis worsening in 42.1%; fibrosis improved without NASH worsening in 78.8% (95% confidence interval [CI]: 66.0-91.2, 26.8-58.2, and 63.0-91.3) (all P <0.001). MRI-PDFF discriminated the presence and grading of hepatic steatosis (area under the curve [AUC], 0.94 and 0.95, respectively), indicating liver fat remission (<3.3% or 5.0% at 1 year) in 72.2% or 90.4% of patients (95% CI: 58.4%-83.5% or 78.9%-95.5%; all P <0.001). A ≥78.8% relative decline in MRI-PDFF within 1 year differentiated NAS improvement from non-NAS improvement (AUC, 0.912; 95% CI: 0.79-1.00). Compared to non-NASH remission, NASH remission was associated with significant pre- or postoperative regulation of protein expression levels.
Conclusions: These findings can help evaluate the expected histological response, and aid in understanding the proteomic features resulting from the beneficial surgical effects on NAFLD and its advanced stages in patients with obesity.
Keywords: MRI-PDFF; NAFLD; bariatric surgery; cohort study; histology.
Copyright © 2025 The Author(s). Published by Wolters Kluwer Health, Inc.