Relationship among Parkinson’s disease, constipation, microbes, and microbiological therapy

Figure 1 Changes in microbiota composition and metabolites have been associated with the pathogenic mechanisms of Parkinson’s disease-related constipation. Microbiota in patients with Parkinson’s disease exhibited a shift in colonic microbiota metabolism away from carbohydrate fermentation and toward proteolysis, resulting in decreased short-chain fatty acids (SCFAs) production and increased proteolytic metabolite levels. Reduced SCFAs production causes a delay in colon transit time. Enhanced proteolytic fermentation has been linked to increased colon transit time. GLP-1: Glucagon-like peptide 1; PD: Parkinson’s disease; PYY: Peptide tyrosine tyrosine; α-syn: α-synuclein; 5-HT4R: 5-HT4 receptors; 5-HT3R: 5-HT3 receptors; EECs: Enteroendocrine cells; GPCR: G protein-coupled receptors; LPS: Lipopolysaccharide; SCFAs: Short-chain fatty acids.