Introduction: The pathogenesis of prostate enlargement is unknown. Recently, it has been reported that there are microbiotas in various parts of human body and that they play a functional role. We hypothesized that the prostate also contains microbiota, which may affect prostate enlargement. To confirm this hypothesis, we investigated the characteristics of the prostatic microbiota associated with prostate enlargement.
Methods: Prostate tissues were sampled aseptically from patients who underwent a surgery containing prostate resection at our institution between February 2020 and July 2021. In cases of radical prostatectomy for prostate cancer, a site that supposed to be a non-cancerous site was sampled. Their prostate microbiota compositions were analyzed by 16S rRNA gene sequencing. The samples were excluded when cancerous tissue was found adjacent to sampled tissue in the pathological examination. Patients with prostate volumes ?30ml were defined as the prostate-enlargement (PE) group; patients with prostate volumes <30ml were defined as the non-PE group. The alpha and beta diversity of the prostatic microbiota were compared between the two groups.
Results: Prostate tissues were sampled from 49 patients. The 16S rRNA gene sequencing was performed on 47 prostate tissue samples, excluding 2 samples in which cancerous tissue was detected in adjacent tissue. The PE group included 34 patients; the non-PE group included 13 patients. In evaluating alpha diversity, Chao1 index was significantly lower in the PE group (150 vs 225, p = 0.02) and Faith phylogenic diversity was tend to be lower in the PE group (49 vs 55, p=0.04). No significant difference was identified in the beta diversity between the two groups.
Conclusions: Chao 1 index in alpha diversity was found to be associated with prostate enlargement, suggesting that the prostatic microbiota affects prostate enlargement.
Source of Funding: This work was supported by JSPS KAKENHI.