Endometrial polyps and micropolyps. Microbial landscape of the uterine cavity and its role in their formation

Abstract

Endometrial polyp is the most common structural abnormality of the mucous membrane of the uterus (endometrium) detected in unexplained infertility. Endometrial micropolyps are a hysteroscopic sign of chronic endometritis, detectable in 60% of women suffering from infertility. Both of the lesions provide an unfavorable environment for the endometrium receptivity and therefore may have common features in their etiopathogenesis. Study objective: to study the composition of microbiota in the vagina, the cervix and the uterine cavity in women of reproductive age diagnosed with endometrial polyps and micropolyps. Study design: the study involved 130 patients aged 18–35 years: 70 patients with endometrial polyps (group I), 30 patients with micropolyps (group II) and 30 patients of the control group (group III). Study methods: group I and II were diagnosed by hysteroscopy with histological confirmation, endometrial samples from healthy women were obtained by aspiration biopsy. Test system “Femoflor” was used to study the quantitative composition of vaginal microbiota, bacteriological examination of the cervix and the endometrium was performed by PCR and by cultivating aerobic and anaerobic microorganisms on special growth media. Study results: no statistically significant differences in the quantitative composition of vaginal microbiota have been identified in all study groups, the only changes recorded have been in the number of lactobacilli. The control group reported sufficient content of lactobacilli in 63% of women studied, the group I – 39%, the group II – from 23%. The cervical canal was sterile in 29% of women with polyps, 47% of women with micropolyps and 30% of healthy patients. The spectrum of pathogens isolated from the cervical canal was much narrower as opposed to the vagina and had no statistically significant differences between the groups. The frequency of the uterine cavity infection was 83% in women of group I, 73% in group II and 77% in group III. The endometrium of the patients from the control group has been seeded with noticeably more Enterococcus faecalis (43% vs. 11% in group I and 17% in group II). Endometrial samples of women from group I were characterized by significantly higher detection of Candida spp. – 21%, and herpes viruses type 1, 2, and 6 – 17%. The spectrum of microorganisms isolated from the endometrium of women with micropolyps did not significantly differ from that in the control group. Evaluation of concordance of the vaginal and endometrial biotope in all groups has not shown any significant differences but in Enterococcus faecalis in the I group (0 vs. 11%) and group III (0 to 43%). When comparing cervical and endometrial biotope the only significant difference has been detected in the group of women with endometrial polyps and concerned herpes virus type 6 (0 vs 11%) as well as the high-risk strains of HPV (31% vs. 6%). The limitations of this study: isolated endometrial pathogens were not correlated with the qualitative and quantitative composition of the gastrointestinal microbiota; further reliable data can be obtained from the detailed study of the nature of immune response in women with a variety of viral agents detected in the uterine cavity, as well as from classifying them according to the obtained results and building a more large-scale research. Conclusions: endometrial polyps and micropolyps – a pathology that results from dysbiotic changes in the vagina. The presence of microbial agents in the uterine cavity is not always indicative of the inflammatory processes. No convincing evidence of the etiologic role of any infection in the micropolyps formation has been obtained. Women with endometrial polyps demonstrated higher content of Candida spp. and viruses.