Introduction
Women with Premature Ovarian Insufficiency (POI) present a premature
reduction in ovarian activity, with serum concentration of sex hormones
reduction, especially estrogen, establishing body repercussions. POI
affects approximately 1% of the sexually active female population, but
it increases the risk of various diseases. (1)
Studies have shown psychological repercussions, impairment of
cardiovascular health; bone mass; urogenital system; reproduction;
sexual function; quality of life and even a reduction of life expectancy
when POI is not adequately treated. One of the pillars for POI treatment
is systemic hormonal therapy (HT). (1, 2-6 )
Prolonged hypoestrogenemia also lead to vulvovaginal atrophy.
Hypoestrogenism leads to macroscopic, histological and functional
changes, which are progressive over time (7,8). The balance of the
vaginal ecosystem is crucial to maintain vaginal health, especially in
women with preserved sexual activity. Women with POI are young and
expect to have sexual activity like any other woman without estrogen
deficiency.
Estrogen promotes the preservation of a homeostatic (eubiotic) vaginal
microenvironment. It is a key part of promoting accumulation of glycogen
in the cells of the vaginal mucosa, by the action of α-amylase. A
glycogen-rich vaginal milieu is propitious
of Lactobacilli proliferation, facilitated by lactic acid
production and decreased pH. Therefore, the predominant presence of
Lactobacillus (LB) in the vaginal ecosystem is fundamental. Lactic acid,
produced by LBs, promotes an increase in the TH17 immune response and
inhibits the proliferation of harmful anaerobic bacteria in the
extracellular matrix of the tissue (9). However, recently,
identification techniques for bacteria have revolutionized the study of
microorganisms. The use of amplification, cloning techniques and
subsequent analysis of sequences of bacterial genes (genes that codify
for bacterial rRNA 16 S) in samples of vaginal secretion have identified
the majority of species of Lactobacilli and other microorganisms. These
techniques demonstrated that Lactobacilli sp don’t always correspond to
the dominant species in the vagina of healthy women (10). Vaginal
ecosystem of POI women studies were carried out focusing on the
maturation of the epithelial cells (vaginal mucosa) and the lubrication
that is obtained with HT. There is a scarce data of microbiota and the
vaginal microbiome. In one of the rare literature studies with such a
focus, were studied women with POI receiving HT and evaluated the
vaginal microenvironment through amine testing, bacterioscopy, and
fungal specific culture. The vaginal flora of these women was similar to
women with same age and with preserved gonadal function (11). This flora
was made up predominantly of Lactobacillus sp.
Lactobacilli and their antimicrobial and anti-inflammatory
products along with components of the epithelial mucosal barrier provide
an effective first line defense against invading pathogens including
bacterial vaginosis, aerobic vaginitis-associated bacteria, viruses,
fungi and protozoa(9), So, the human vaginal microbiota appears to play
an important role in preventing numerous urogenital diseases. . General
consensus attributes this to lactic acid producing bacteria, mainly
Lactobacillus sp, (12).
However, the methodology usually used for this identification has
limitations in terms of the specificity for the identification of
microorganisms that inhabit the human body.. A feature that has been
recently studied, and has proven to be quite efficient, is the study of
the microbiome. Microbiome is the totality of microorganisms, their
genetic elements (genome), and interactions in a specific environment
(13). Modern DNA tests have made it possible to identify most of these
microorganisms, since they are not easily grown in the laboratory (14).
DNA-based Microbiome studies can be categorized as amplicon specific
studies or, more recently, metagenomic studies. It is a challenge not to
include host DNA in the study (13). After the Amplicons are sequenced,
phylogenetic molecular methods are used to infer the composition of the
microbial community. To determine the identity of a phylogenetic
sequence, it is compared to the complete genomic sequences available
using methods such as the BLAST programs (13).
The vaginal microbiome of women with IOP has not been described. Thus,
this study was developed with the objective of evaluating the vaginal
flora of women with POI receiving HT verifying the microbiome by
bacterial (16S rRNA) DNA extraction methods.