Untargeted Serum Metabolomics Reveals Metabolic Disturbances in Children with MASLD: A Preliminary Study

Pediatric metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as a major public health concern. The pediatric form of MASLD differs from the adult phenotype in its pathophysiology and exhibits distinct histopathological characteristics. This study aimed to characterize serum metabolomic alterations associated with pediatric MASLD and to identify metabolic signatures that may provide further insight into the disease phenotype. To this end, untargeted metabolomic analysis was performed on serum samples from 21 pediatric MASLD patients and 22 healthy controls using liquid chromatography coupled with high-resolution quadrupole time-of-flight mass spectrometry (LC-MS/QTOF). Univariate statistical analysis was performed using the Mann–Whitney U-test with false discovery rate (FDR) correction, while multivariate analysis employed principal component analysis and orthogonal partial least squares discriminant analysis (OPLS-DA). Multivariate analysis in the positive ionization mode demonstrated clear separation between the MASLD and control groups (R2Y = 0.972, Q2 = 0.823, CV-ANOVA p-value = 2.387 × 10−10). A total of 46 annotated metabolites differed significantly between the groups. The most pronounced alterations involved bile acid and sterol metabolism, including increased 12α-hydroxy-3-oxocholadienic acid and decreased conjugated primary bile acids, including taurine and glycine conjugates. In addition, increased levels of free carnitine and short-chain acylcarnitines, together with alterations in free and oxidized fatty acids, suggested disturbances in fatty acid metabolism. The metabolomic profile also revealed broad disruption of glycerophospholipid metabolism, characterized primarily by decreased lysophosphatidylcholines and lysophosphatidylethanolamines. In conclusion, the metabolomic profile of pediatric MASLD indicates pronounced systemic metabolic alterations, primarily involving lipid and fatty acid metabolism, bile acid and sterol metabolism, and amino acid-related pathways. The coordinated pattern of these changes suggests alterations across multiple interconnected metabolic processes, highlighting the complex metabolic phenotype of pediatric MASLD. The identified metabolic signatures provide a basis for further investigation and warrant validation in larger, independent cohorts to determine their biological and potential clinical relevance.