Constipation Severity Affects the Gut Microbiome Composition of Parkinson’s Disease Patients

Abstract

Parkinson's disease (PD) is a complicated brain disorder caused by a variety of environmental and genetic factors. Besides the neurological deficits associated with PD, there are many physiological changes associated with the disease, such as digestive issues. In fact, PD patients are particularly vulnerable to suffering from constipation, and studies have shown that there is a bi-directional relationship between the gut microbiome of PD patients and constipation. However, the variables that contribute to changes related to PD, and constipation in the gut microbiome are largely unknown. In this study, we aimed to determine if there is a relationship between the gut microbiome of PD patients and the severity of their constipation. First, we used alpha and beta diversity analysis to determine a relationship between constipation severity and the gut microbiome of PD patients. Differential and relative abundance analysis of the amplicon sequence variants (ASVs) present in the highest and lowest constipation severity categories also indicate that particular genera may drive some of the differences identified in high constipation categories compared to lower severity categories in this study. We found that there were less unique amplicon sequence variants (ASVs) identified in the gut microbiome samples of higher constipation severity groups as compared to lower constipation severity groups. Abundance analysis of ASVs showed three distinct genera: Lachnospiraceae, Faecalibacterium, and Bifidobacterium that are differentially abundant in the high constipation severity group compared to the no constipation group. These insights have improved our understanding of the relationship between constipation severity and the gut microbiome of PD patients.