Current findings in endometrial microbiome: impact on uterine diseases

Abstract

Microbiome or microbiota is essential to regulate many mammalian physiological processes, including reproduction. Like other organs or tissues, the upper female reproductive tract (FRT) used to be considered devoid of microorganisms; however, a not-infection-related bacterial community was discovered in uteri from humans and other mammals, and its composition is related to reproductive success. The dysbiosis of endometrial microbiota is associated with benign and malign uterine diseases. Hence, this review addressed the current knowledge about uterine microbiota alterations and their association with common endometrial diseases, including endometrial polyposis, endometriosis, uterine myomatosis, endometrial hyperplasia, and endometrial cancer. There is a specific bacterial community in the endometrium In most analyzed uterine diseases. However, the constant finding consists in a reduced abundance of Firmicutes and Lactobacillus, while there is an increased abundance of Proteobacteria (such as E. coli and Enterococcus), Bacteroidetes (Prevotella, for example), and Actinobacteria (as Gardnerella), in contrast to healthy endometrium. Besides, we discussed the future usefulness of the endometrial microbiota components as biomarkers to diagnose uterine diseases and their probable clinical outcomes. In addition, we analyzed their potential use as probiotics since they could provide an alternative or complement to existing therapies.

Comparison of Metagenomics and Metatranscriptomics Tools: A Guide to Making the Right Choice

“…Considering the literature, we note that at the genus level, both obtained results in line with other authors, given that the abundant genera in endometrium and/or endometrial cancer are Bacteroides, Prevotella, Pseudomonas, Acinetobacter and Rheinheimera [ 172 , 190 ] (see Figure 11 ). In terms of species, those provided by QIIME2 do not appear to be related to this tissue, nor to this disease.…”

“…In terms of species, those provided by QIIME2 do not appear to be related to this tissue, nor to this disease. However, the species provided by Kraken using Refseq as a reference do resemble some known species, such as E. coli as well as various Acinetobacters and Pseudomonas [ 172 , 190 ] (see Figure 12 ).…”

Endometrial microbiota from endometrial cancer and paired pericancer tissues in postmenopausal women: differences and clinical relevance

“…The uterus was long considered to be sterile, but current knowledge suggests that the uterus in healthy or diseased conditions harbors its own microbiota. [22][23][24][25] Endometrial microbiota has been preliminarily proven to be involved in several gynecological disorders, including chronic endometritis, infertility, endometriosis, dysfunctional menstrual bleeding, and EC. [26][27][28][29][30][31] Indeed, many clinical factors may independently influence the endometrial microbiome structure.…”

Endometriosis as an Infectious Disease: Association with Chronic Endometritis

“…While there are three major theories underlying the onset of endometriosis (i.e., retrograde menstrual blood flow, coelomic metaplasia, and Mullerian remnants), a single one is unable to explain the whole entity of the disease. Given the immunological and inflammatory natures of endometriosis, it is conceivable that bacterial infection and their metabolites are involved in this pathology [18].…”