Shedding light on Endometriosis disease: Analyzing the role of Genetics, Diet and Microbiome on a highly characterized cohort

EM is a chronic, inflammatory, and multifactorial disease. Concerning genetics, the genes and variants involved are poorly elucidated. Regarding the environment, diet and microbiome are emerging players in EM; however, the knowledge of the causal links between these factors and EM is far to be completed. In this context, the role of extra-oral taste-associated genes (TGs), whose activity modulates nutritional habits and inflammatory processes and are reported to interact with microbiota, could provide novel mechanistic insights underlying EM. This project aims to analyze: 1) the genetic bases of EM, 2) the role of diet and TGs genetic variants in modulating EM symptoms severity, 3) the impact of the gut microbiota in EM development. In this framework, also the role of TGs on the gut microbiome composition was evaluated. To these aims, a cohort of 103 EM patients was enrolled at IRCCS “Burlo Garofolo” hospital (Trieste, Italy). A detailed clinical evaluation was performed, collecting data on personal, familial anamnesis, EM-associated symptoms, information on diet and food preferences. Furthermore, a blood sample was collected to perform Whole-Exome Sequencing (WES) analysis. Finally, for a subgroup of patients undergoing surgery (n=51), rectal swabs were picked up for microbiome analyses. Concerning 1), WES focused on a list of 46 selected genes, thus allowing the a) identification of 47 rare heterozygous and predicted damaging variants within 24/46 genes in 43/103 (41.7%) of the EM patients; b) definition of novel possible genotype-phenotype correlations with a potential translational value. Regarding 2) statistical analyses revealed that legumes and dairy products consumption was found to worsen the severity of, respectively, dysmenorrhea (p=0.048) and post-menstrual pain (p=0.024). Furthermore, concerning TGs, it was obtained that carriers of at least one alternative allele of rs35874116 within the TAS1R2 gene were exposed to a lower dysmenorrhea risk (p=0.033, odds ratio: 0.208). Finally, regarding 3) gut microbiome data analyses allowed to detect that: • the alpha diversity correlated negatively with the premenstrual pain severity (p=0.007). • A lower beta diversity was associated with an EM-infertility diagnosis (p=0.02). Moreover, TGs have been investigated in relation to EM microbiome, revealing that patients carrying at least one non-functional allele of TAS2R38 gene showed the lowest beta diversity compared to wild-type genotype carriers (p=0.01). In conclusion, this study provided a comprehensive view of EM, spanning from clinics, genetics, diet and microbiome, and analyzed, for the first time, the role of TGs, thus opening novel insights into their role in inflammation and dysbiosis. The results of this project could be considered as a possible starting point for the future definition of novel therapeutic strategies, aimed at improving patients’ quality of life.