Gut mycobiome in the spectrum of Metabolic-dysfunction Associated Steatotic Liver Disease (MASLD): from MASH to hepatocellular carcinoma.

UNLABELLED: Gut Microbiome (GM) dysbiosis is associated with the development and progression of Metabolic-dysfunction Associated Steatotic Liver Disease (MASLD) and steatohepatitis (MASH). Human GM contains bacteria, fungi, archaea, and viruses. Gut mycobiome (GMyco) is still poorly studied in patients with MASLD. Herein we investigated GMyco composition at different MASLD stages.

METHODS

23 patients were recruited: controls (n = 5); MASH (n = 6); cirrhosis (n = 7); and Hepatocellular Carcinoma (HCC) (n = 5). Stool samples were collected and stored in -80 °C for subsequent DNA extraction and profiled by 18S rRNA sequencing. The single sequence variants obtained were inferred with DADA2 and classified with SILVA v138. Diversity metrics (Simpson; Bray-Curtis PERMANOVA) and DESeq2 with BH FDR were used for statistical analysis.

RESULTS

Among 23 participants, 73.9% were women, and the average BMI was 30.7 kg/m2. Current alcohol use was reported in 17.4%, and chronic medication use in 56.5% of individuals. MASH patients showed greater gut mycobiota alpha diversity compared with controls (p < 0.05). Controls exhibited higher relative abundance of the phylum Ascomycota, whereas Basidiomycota predominated in MASH. At the family level, Aspergillaceae was more abundant in controls, Malasseziaceae and Sporidiobolaceae in cirrhosis, and Saccharomycetaceae in HCC. Differential abundance analysis identified three ASVs differing between groups, with one ASV (genus Naganishia) homogeneously distributed in MASH and absent in controls.

CONCLUSIONS

The gut mycobiota profile varied across the MASLD spectrum, with stage-specific enrichment of certain taxa despite overall similarity in community structure. Basidiomycetes ‒ notably Malassezia and Naganishia ‒ were more abundant in MASH, while Saccharomyces dominated in advanced stages. These findings suggest that distinct fungal signatures accompany disease progression and may serve as potential biological markers in MASLD.