Altered gut microbial networks and metabolic pathways in multiple system atrophy

This study aimed to identify key gut microbial interaction networks in multiple system atrophy (MSA). Demographic information and frozen fecal specimens were collected from 119 participants (MSA, n = 26; Parkinson's disease (PD), n = 66; healthy control (HC), n = 27) at the National Taiwan University Cancer Center (NTUCC), Taipei, Taiwan, from August 2020 to December 2022. Patients meeting the criteria for clinically probable MSA according to the 2022 Movement Disorder Society criteria, as well as patients diagnosed with PD based on the UK Parkinson's Disease Society Brain Bank clinical diagnostic criteria, were enrolled. Fecal DNA was extracted from 200 mg frozen samples using the QIAamp Fast DNA Stool Mini Kit (Qiagen, Hilden, Germany). The 341f forward primer and 805r reverse primer were designed to include sequences complementary to the upstream and downstream regions of the 16S rRNA V3-V4 gene segment, along with the Illumina overhang adapter sequences. The dual-index barcodes and the Illumina sequencing adapters were attached to the PCR products using the Nextera XT Index Kit (Illumina, CA, USA). The libraries were cleaned, normalized, pooled, and sequenced using the MiSeq System (Illumina, CA, USA) with V3 reagent for paired-end sequencing.