Materials and Methods
Study design
Cross-sectional study developed at Department of Obstetrics and Gynecology of the School of Medical Sciences, University of Campinas - UNICAMP. This study was approved by the Ethics Committee of the institution under number CAAE 06124512,6,2001,5404. Participants were recruited at the institution’s Endocrinology Gynecology Outpatient Clinic, a tertiary center. This study is a descriptive analysis of the population studied in a larger study comprising a clinical trial with interventions REBEC number RBR-74zbms.
Participants
We included 40 women with POI diagnoses who had been using oral systemic HT for at least 6 months. POI diagnosis was based on hypergonadotrophic amenorrhea with at least two FSH dosages greater than 25 IU/mL (1). All participants signed an Informed Consent Term. Women who had a specific acute infectious process involving vulvovaginitis or ulcers in the genital region, or who had used medications related to mucositis (long-term antibiotics, immunomodulators, chemotherapeutics), and women with systemic or localized allergic conditions, were excluded.
Methodology
All women included in the study collected vaginal secretion with a swab (Eswab Liquid-based Multipurpose Collection and Transport System). The collected samples were vigorously shaken and centrifuged at 800g for 10 minutes and the pellets obtained were submitted to DNA extraction using the MiSeq Reagent Kit (600-cycle), Illumina Brasil Produtos de Biotecnologia Ltda, São Paulo, Brazil, according to the recommended protocol by the manufacturer for DNA extraction from bacteria. The samples were stored as DNA in a biorepository in specific freezers (Freezers at -20C) and used only for this purpose in the specialized clinical laboratory. After thawing, the obtained DNA were quantified and evaluated for purity and quality and were submitted to the technique of Pirsequencing 16S rRNA gene amplicons in the Laboratory of Insulin Resistance of the School of Medical Sciences of the University of Campinas - UNICAMP.
To carry out the 16S rRNA extraction through pyrosequencing, the 16S library preparation protocol was performed. The samples, after reaching room temperature, were submitted to the first stage of PCR (Polymerase Chain Reaction) and then PCR cleaning through the reagents Ampure XP Beads, EtOH 80% fresh, RSB and then placed in PCR postplates. The second PCR stage was performed and the post-PCR cleaning procedure was repeated with the same reagents. Data was then placed into the quantification and normalization library and sequentially in the MiSeq denaturing and loading library of samples. The entire methodology followed the KIT protocol (MiSeq Reagent Kit (600-cycle), Illumina Brasil Produtos de Biotecnologia LTDA, São Paulo, Brazil).
The data of the microbiome, obtained from the pyrosequencing, were sent for analysis to the Scylla bioinformatics service, Campinas, Brazil, for organization and phylogenetic classification to divide the groups according to the cited classification in literature by Ravel (4) as follows: Roman numerals indicate five groups of bacterial vaginal communities. Groups of communities I, II, III and V have as predominant bacterial Lactobacillus crispatus, L. gasseri, L. iners and L. Jensenii, respectively, while group IV contains a diversity of strict or facultative anaerobic bacteria (Prevotella, Dialister, Atopobium, Gardnerella, Megasphaera, Peptoniphilus, Sneathia, Eggerthella, Aerococcus, Finegoldia, and Mobiluncus).
Ravel et al., in a study with healthy young women at reproductive age revealed that in this population, group I communities, which occurred in 26.2%, were dominated by L. crispatus, while groups II (6.3%) , III (34.1%) and V (5.3%) were dominated by L. gasseri, L iners and L. jensenii, respectively (12).
Sample Size Calculation
This descriptive study is a secondary analysis of a clinical trial. The sample size was calculated based on the main objective, which was calculated in 30 patients, divided into two treatment groups. However, in view of possible loss of follow-up, it was decided to include 40 women with POI. The current study represents a descriptive analysis of the vaginal microbiome of the women at the inclusion time of the study.
Data Analysis
To describe the profile of the sample, tables with absolute frequency (n) and percentage (%) values ​​and descriptive statistics of the numerical variables with mean values, standard deviation were made. To classify the samples into their phylogenetic groups according to Ravel, tables were also made with absolute (n) and percentage (%) frequency values. For statistical analysis SAS software was used for Windows version 9.2.