Cross sectional analysis of gut microbiota of ALS patients with and without percutaneous endoscopic gastrostomy.

INTRODUCTION: This cross-sectional study investigated the differences in gut microbiota in patients with Amyotrophic Lateral Sclerosis (ALS) with and without percutaneous endoscopic gastrostomy (PEG), exploring their cross-sectional associations with nutritional intake. METHODS: Use of shotgun metagenomics and dietary assessments. RESULTS: We identified significant taxonomic shifts and changes in diversity across groups. PEG patients exhibited reduced abundance of short-chain fatty acids (SCFAs)- producing genera, such as Faecalibacterium and Lachnospira, suggesting a dysbiotic profile; the Firmicutes/Bacteroidetes ratio was also lower in PEG patients but is reported as a descriptive indicator only. Correlations between specific bacterial taxa and nutrient intake, highlight the potential role of the gut microbiota in ALS pathophysiology. These findings describe cross-sectional differences in microbial composition associated with nutritional status and feeding route. DISCUSSION: Our results provide a foundation for microbiome-targeted interventions in the management of ALS, although findings related to PEG should be interpreted as exploratory given the limited sample size. Furthermore, all comparisons involving the external control group (BioProject PRJNA961076) must be interpreted with caution due to potential batch effects from differences in sample collection, DNA extraction kits, and sequencing platforms.