Dopaminergic Medication Accentuates Fecal Gut Microbiome Changes in Parkinson's Disease

Fecal gut microbiota changes are associated with Parkinson's disease (PD). However, disease related changes cannot readily be discerned from medication effects, as almost all participants in previous studies were using PD medication, and conclusive longitudinal data related to treatment initiation is lacking. Here, fecal gut microbiota composition was assessed in 62 de novo PD participants who were untreated at baseline and used PD medication at one-year follow-up, by means of 16S-sequencing. In addition, participants were stratified for the type of dopaminergic medication. Overall gut microbiota composition did not differ between baseline and one-year follow-up, but was associated with levodopa dose and levodopa equivalent daily dose (LEDD). Several differentially abundant taxa are in line with previously described changes in PD. These included reduced levels of amplicon sequence variants (ASVs) belonging to Faecalibacterium prausnitzii and Lachnospiraceae in all participants at follow-up, and increased levels of an ASV belonging to Bifidobacterium in dopamine agonist users. The family Bifidobacteriaceae was increased in dopamine agonist users who only used pramipexole. Levodopa dose was inversely related to the abundance of the families Ruminococcaceae and Lachnospiraceae, and the genus Lachnospiraceae ND3007 group. PD medications exert a measurable and dose-dependent effect on gut microbiota composition and accentuate several previously described gut microbiota changes in PD. Detailed knowledge of medication effects should be part of future trial designs of gut microbiome studies in PD and are necessary to interpret previously published data.