The Glutamate-Serine-Glycine Index as a Biomarker to Monitor the Effects of Bariatric Surgery on Non-alcoholic Fatty Liver Disease.

OBJECTIVE

Bariatric surgery effectively treats non-alcoholic fatty liver disease (NAFLD). The glutamate-serine-glycine (GSG) index has emerged as a non-invasive diagnostic marker for NAFLD, but its ability to monitor treatment response remains unclear. This study investigates the GSG index's ability to monitor NAFLD's response to bariatric surgery.

METHODOLOGY

Ten NAFLD participants were studied at baseline and 6 months post-bariatric surgery. Blood samples were collected for serum biomarkers and metabolomic profiling. Hepatic steatosis [proton density fat fraction (PDFF)] and fibroinflammation (cT1) were quantified with multiparametric magnetic resonance imaging (mpMRI), and hepatic stiffness with magnetic resonance elastography (MRE). Amino acids and acylcarnitines were measured with mass spectrometry. Statistical analyses included paired Student's t-test, Wilcoxon-signed rank test, and Pearson's correlation.

RESULTS

Eight participants provided complete data. At baseline, all had hepatic steatosis (BMI 39.3 ± 5.6 kg/m, PDFF ≥5%). Post-surgery reductions in PDFF (from 12.4 ± 6.7% to 6.2 ± 2.8%, = 0.013) and cT1 (from 823.3 ± 85.4 ms to 757.5 ± 41.6 ms, = 0.039) were significant, along with the GSG index (from 0.272 ± 0.03 to 0.157 ± 0.05, = 0.001).

CONCLUSION

The GSG index can potentially be developed as a marker for monitoring the response of patients with NAFLD to bariatric surgery.