The Endometrial Microbiome and Its Impact on Human Conception

Toson, Bruno; Simón, Carlos; Moreno-Gimeno, Inmaculada

doi:10.3390/ijms23010485

Cited by 57 publications

(42 citation statements)

References 103 publications

(163 reference statements)

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“…To date, it still remains unclear whether opportunistic microorganisms detected in the endometrium have a negative impact on implantation, what composition of the uterine microbiota is considered to be normal and which one is associated with dysbiosis having an adverse effect on implantation, and where is the line between the norm and pathology in quantitative and qualitative ratio [ 10 – 13 ].…”

Section: Introductionmentioning

confidence: 99%

Does the uterine microbiota affect the reproductive outcomes in women with recurrent implantation failures?

et al. 2022

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Background Inefficiency of in vitro fertilization (IVF) programs can be caused by implantation failures. The uterine microbiota can influence the implantation process. However, it still remains unclear whether opportunistic microorganisms detected in the endometrium have a negative impact on the implantation success. The aim of our study was to evaluate the influence of the uterine microbiota on the embryo implantation success in patients undergoing assisted reproductive technologies. Methods The study included 130 women diagnosed with infertility. The patients were divided into three groups: group I included women with the first IVF attempt (n = 39); group II included patients with recurrent implantation failure following embryo transfer with ovarian stimulation (n = 27); group III consisted of women with recurrent implantation failure following frozen-thawed embryo transfer (n = 64). We performed microbiological examination of the embryo transfer catheter which was removed from the uterine cavity after embryo transfer; cervical discharge of all the patients was studied as well. Thirty patients were selected for metagenomic sequencing. Results The study showed that the uterine cavity is not free of microorganisms. A total of 44 species of microorganisms were detected: 26 species of opportunistic organisms and 18 species of commensals (14 species of lactobacilli and 4 species of bifidobacteria). Obligate anaerobic microorganisms and Gardnerella vaginalis were detected more frequently in group I compared to group III (strict anaerobes—15.4 and 1.6%; G. vaginalis—12.8 and 1.6%, respectively) (p < 0.05). However, this fact did not have a negative influence on the pregnancy rate: it was 51.3% in group I, it was 29.6% and 35.9% in women with recurrent implantation failures, respectively. Conclusion Opportunistic microorganisms which were revealed in low or moderate titers (103–105 CFU/ml) in the uterine cavity and cervical canal did not affect the pregnancy rate in the women in the study groups. The microflora of the uterine cavity and cervical canal differed in qualitative composition in 87.9% of patients, therefore, we can suggest that the uterine cavity may form its own microbiota. The microbiota of the uterine cavity is characterized by fewer species diversity compared to the microbiota of the cervical canal.

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Section: Introductionmentioning

confidence: 99%

Does the uterine microbiota affect the reproductive outcomes in women with recurrent implantation failures?

et al. 2022

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“…The results of HMP1 confirmed this and identified four Lactobacillus species ( L. crispatus , L. gasseri , L. iners , and L. jensenii ) [ 55 ]. The critical role of vaginal Lactobacillus is the production of lactic acid, which significantly contributes to the maintenance and homeostasis of the mucosal bacterial microenvironment by dropping the local potential of hydrogen [ 56 ]. Other molecules synthesized by local Lactobacillus , such as bacteriocins and hydrogen peroxide, also contribute to the impaired proliferation of pathogenic micro-organisms.…”

Section: Challenges In Clinical Diagnosis Of Microbial Ce: What Is Th...mentioning

confidence: 99%

Challenges in Clinical Diagnosis and Management of Chronic Endometritis

Yasuo

Kitaya²

2022

Diagnostics

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Chronic endometritis (CE) is a local mucosal infectious and inflammatory disorder characterized by unusual filtration of CD138(+) endometrial stromal plasmacytes. CE is attracting attention due to its potential association with infertility of unknown etiology, repeated implantation failure, recurrent pregnancy loss, and several maternal/neonatal complications. Due to the variance in study design among researchers, universal diagnostic criteria remain to be established for the clinical diagnosis and management of CE. This review article aims to summarize current knowledge and provide insights into unsolved questions on CE to establish clinical guidelines for the disease from the viewpoint of human reproduction.

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“…Based on the collected data in the literature, scientists speculate that microbes interact with the endometrial epithelium and/or change the immunity of the mucosa through several mechanisms, including altered expression of genes encoding proteins involved in the inflammatory response, proliferation, and apoptosis in the endometrium, or through a series of immune-mediated changes, such as abnormal expression of leukocyte subsets, altered secretion of antibodies and cytokines, and immunoglobulins [ 118 , 119 ]. Consequently, these events—isolated or in combination—can ultimately disrupt various processes and promote the development of pathological conditions such as chronic endometritis, eventually resulting in the development of neoplastic diseases.…”

Section: Microbial Dysbiosis and Its Immune Implications Related To E...mentioning

confidence: 99%

The Role of Microbiota in the Immunopathogenesis of Endometrial Cancer

Sobstyl

Brecht

Sobstyl

et al. 2022

IJMS

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The female reproductive tract hosts a specific microbiome, which plays a crucial role in sustaining equilibrium and good health. In the majority of reproductive women, the microbiota (all bacteria, viruses, fungi, and other single-celled organisms within the human body) of the vaginal and cervical microenvironment are dominated by Lactobacillus species, which benefit the host through symbiotic relationships, in comparison to the uterus, fallopian tubes, and ovaries, which may contain a low-biomass microbiome with a diverse mixture of microorganisms. Although disruption to the balance of the microbiota develops, the altered immune and metabolic signaling may cause an impact on diseases such as cancer. These pathophysiological modifications in the gut–uterus axis may spark gynecological cancers. New information displays that gynecological and gastrointestinal tract dysbiosis (disruption of the microbiota homeostasis) can play an active role in the advancement and metastasis of gynecological neoplasms, such as cervical, endometrial, and ovarian cancers. Understanding the relationship between microbiota and endometrial cancer is critical for prognosis, diagnosis, prevention, and the development of innovative treatments. Identifying a specific microbiome may become an effective method for characterization of the specific microbiota involved in endometrial carcinogenesis. The aim of this study was to summarize the current state of knowledge that describes the correlation of microbiota with endometrial cancer with regard to the formation of immunological pathologies.

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The Endometrial Microbiome and Its Impact on Human Conception

Cited by 57 publications

References 103 publications

Does the uterine microbiota affect the reproductive outcomes in women with recurrent implantation failures?

Does the uterine microbiota affect the reproductive outcomes in women with recurrent implantation failures?

Challenges in Clinical Diagnosis and Management of Chronic Endometritis

The Role of Microbiota in the Immunopathogenesis of Endometrial Cancer

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