GUT, VAGINAL AND URINARY MICROBIOTA AS POTENTIAL BIOMARKERS OF SENSITIZATION IN WOMEN WITH CHRONIC PELVIC PAIN.

BACKGROUND A subgroup of patients with chronic pelvic pain (CPP) exhibit organ sensitization, whose origin and mechanism remains largely unknown. Changes in microbiota composition in pelvic organs have been found to be associated with various pelvic pathological conditions. Therefore, a comprehensive analysis of the gut and genito-urinary microbiota composition and interactions in women with CPP may be key to understanding their involvement in the sensitization processes. OBJECTIVE To identify pelvic organ microbiota signatures that are associated with organ hypersensitivity in CPP patients. STUDY DESIGN This study involved women with high (S-CPP, n=14) and low (NS-CPP, n=14) pelvic sensitization scores according to the Convergences PP criteria. Pelvic organ sensitivity was assessed by rectal barostat, and noninvasive bladder, muscular and vulvar sensory tests. Quality of life, pelvic symptoms and psychological state were assessed. Using 16S rRNA gene sequencing, the gut, vaginal and urinary microbiota diversity and composition were analyzed and compared between S-CPP and NS-CPP women. Differentially abundant bacterial amplicon sequence variants (ASVs) between groups were associated with clinical characteristics and organ sensitivity. System biology approaches using Weighted Gene Correlation Network Analysis (WGCNA) were used to identify bacterial ASV modules associated with functional and clinical parameters. RESULTS Pain pressure thresholds were significantly decreased in S-CPP women for the vulva and for the rectum, the bladder and the perineal muscles as compared to NS-CPP. However, pain intensity felt at rectal, muscular and bladder pain thresholds was significantly increased in S-CPP women. After stimulation, S-CPP women presented increased and prolonged pain in perineal muscles and bladder compared to NS-CPP women. Alpha and β-diversities were significantly increased in S-CPP women in vaginal and urinary but not in gut microbiota. Using, differential abundance analysis, we showed that 13 ASVs in the gut, 6 in the vagina and 2 in the bladder were differentially expressed between S-CPP and NS-CPP patients. More specifically, in vaginal microbiota, a significant increase of Streptococcus and Prevotella genera was observed in S-CPP as compared to NS-CPP. A significant increase in Clostridium sensu stricto 1 ASV was observed in urinary microbiota of S-CPP as compared to NS-CPP patients. Next, we found that 4 gut microbiota ASVs (belonging to Akkermansia, Desulfovibrio, Faecalibacterium and CAG-352) were correlated with pain intensity at maximal rectal distension threshold. We also identified an ASV (Blautia) which is increased in NS-CPP as being inversely correlated to several gut sensitization markers. In the vaginal microbiota, the Lactobacillus jensenii ASV was associated with less dysmenorrhea and an increased bladder capacity. Furthermore, we identified two vaginal ASVs belonging to Prevotella which are increased in S-CPP as being associated with dysmenorrhea. Finally, using WGCNA analysis methods, we identified vaginal and urinary tract ASVs modules driven by Peptostreptococcales-Tissierellales Peptoniphilus which were strongly correlated with rectal, muscular and bladder poststimulation pain. We also identified a gut ASVs module driven by Christensenellaceae_R-7 that significantly associated with anxiety, gastro-intestinal symptoms and rectal sensitivity. CONCLUSIONS This work identified specific bacterial signatures of specific pelvic organs and their association with organ sensitization, which are potential therapeutic targets in CPP women.