Characteristics of Gut Microbiota in Patients with Erectile Dysfunction: A Chinese Pilot Study

Purpose: Little is known about the role of gut microbiota in the pathogenesis of erectile dysfunction (ED). We performed a study to compare taxonomic profiles of gut microbiota of ED and healthy males.Materials and Methods: A total of 43 ED patients and 16 healthy controls were enrolled in the study. The 5-item version of the International Index of Erectile Function (IIEF-5) with a cutoff value of 21 was used to evaluate erectile function. All par-ticipants underwent nocturnal penile tumescence and rigidity test. Samples of stool were sequenced to determine the gut microbiota.Results: We identified a distinct beta diversity of gut microbiome in ED patients by unweighted UniFrac analysis (R2=0.026, p=0.036). Linear discriminant analysis effect size (LEfse) analysis showed Actinomyces was significantly enriched, whereas Coprococcus_1, Lachnospiraceae_FCS020_group, Lactococcus, Ruminiclostridium_5, and Ruminococcaceae_UCG_002 were depleted in ED patients. Actinomyces showed a significant negative correlation with the duration of qualified erection, average maximum rigidity of tip, average maximum rigidity of base, tip tumescence activated unit (TAU), and base TAU. Co-prococcus_1, Lachnospiraceae_FCS020_group, Ruminiclostridium_5, and Ruminococcaceae_UCG_002 were significantly correlated with the IIEF-5 score. Ruminiclostridium_5 and Ruminococcaceae_UCG_002 were positively related with average maximum rigidity of tip, average maximum rigidity of base, increment Tumescence of tip, and Tip TAU. Further, a random forest classi-fier based on the relative abundance of taxa showed good diagnostic efficacy with an area under curve of 0.72.Conclusions: This pilot study identified evident alterations in the gut microbiome composition of ED patients and found Acti-nomyces was negatively correlated with erectile function, which may be a key pathogenic bacteria.