La morphologie embryonnaire a-t-elle encore un intérêt à l’heure actuelle ?

Extracellular cell-free RNA profile in human large follicles and small follicles

Background: Previous studies have shown that a large number of valuable and functional cell-free RNAs (cfRNAs) were found in follicular fluid. However, the species and characteristics of follicular fluid cfRNAs have not been reported. Furthermore, their implications are still barely understood in the evaluation of follicular fluid from follicles of different sizes, which warrants further studies.

Objective: This study investigated the landscape and characteristics of follicular fluid cfRNAs, the source of organization, and the potential for distinguishing between follicles of different sizes.

Methods: Twenty-four follicular fluid samples were collected from 20 patients who received in vitro fertilization (n = 9) or ICSI (n = 11), including 16 large follicular fluid and 8 small follicular fluid samples. Also, the cfRNA profile of follicular fluid samples was analyzed by RNA sequencing.

Results: This result indicated that the concentration of follicular fluid cfRNAs ranged from 0.78 to 8.76 ng/ml, and fragment length was 20–200 nucleotides. The concentration and fragment length of large follicular fluid and small follicular fluid samples were not significantly different (p > 0.05). The technical replica correlation of follicular fluid samples ranged from 0.3 to 0.9, and the correlation of small follicular fluid samples was remarkably (p < 0.001) lower than that of large follicular fluid samples. Moreover, this study found that cfRNAs of the follicular fluid could be divided into 37 Ensembl RNA biotypes, and a large number of mRNAs, circRNAs, and lncRNAs were observed in the follicular fluid. The number of cfRNAs in large follicular fluid was remarkably (p < 0.05) higher than that of small follicular fluid. Furthermore, the follicular fluid contained a large amount of intact mRNA and splice junctions and a large number of tissue-derived RNAs, which are at a balanced state of supply and elimination in the follicular fluid. KEGG pathway analysis showed that differentially expressed cfRNAs were enriched in several pathways, including thyroid hormone synthesis, the cGMP-PKG signaling pathway, and inflammatory mediator regulation of TRP channels. In addition, we further showed that four cfRNAs (TK2, AHDC1, PHF21A, and TTYH1) serve as a potential indicator to distinguish the follicles of different sizes. The ROC curve shows great potential to predict follicular fluid from follicles of different sizes [area under the curve (AUC) > 0.88].

Conclusion: Overall, our study revealed that a large number of cfRNAs could be detected in follicular fluid and could serve as a potential non-invasive biomarker in distinguishing between follicles of different sizes. These results may inform the study of the utility and implementation of cfRNAs in clinical practice.

[Circulating nucleic acids and infertility]

Circulating nucleic acids (cell-free DNA and microRNAs) have for particularity to be easily detectable in the biological fluids of the body. Therefore, they constitute biomarkers of interest in female and male infertility care. Indeed, in female, they can be used to detect ovarian reserve disorders (polycystic ovary syndrome and low functional ovarian reserve) as well as to assess follicular microenvironment quality. Moreover, in men, their expression levels can vary in case of spermatogenesis abnormalities. Finally, circulating nucleic acids have also the ability to predict successfully the quality of in vitro embryo development. Their multiple contributions during assisted reproductive technology (ART) make of them biomarkers of interest, for the development of new diagnostic and/or prognostic tests, applied to our specialty. Circulating nucleic acids would so offer the possibility of personalized medical care for infertile couples in ART.

Follicular fluid and mural granulosa cells microRNA profiles vary in in vitro fertilization patients depending on their age and oocyte maturation stage

OBJECTIVE

To determine whether there is any difference in the follicular fluid (FF) microRNA (miRNA) profiles from in vitro fertilization (IVF) patients according to their age and oocyte maturation stage.

DESIGN

Observational prospective study.

SETTING

IVF clinic/hospital facilities.

PATIENTS(S)

We included 30 women with primary infertility undergoing intracytoplasmic sperm injection treatment and excluded patients with polycystic ovarian syndrome, endometriosis, severe male factor, and low ovarian reserve.

INTERVENTION(S)

After the collection of FF and granulosa cells from each patient, the samples were processed for total RNA extraction. RNA was pooled into different groups (three samples per pool) for microarray analysis to evaluate the expression of a total of 866 human miRNAs. Individual samples were analyzed to validate the pooled microarray results using real-time polymerase chain reaction.

MAIN OUTCOME MEASURE(S)

Evaluation of the expression of a total of 866 human miRNAs in FF and granulosa cells.

RESULT(S)

We identified only one differentially expressed miRNA, hsa-miR-424, which is present in higher proportions in FF from patients with advanced age. When we compared the FF from metaphase II (MII) versus GV (germinal vesicle) oocytes, we found 13 differentially expressed miRNAs (two up- and 11 downregulated). When we compared FF from MII versus MI, we found seven differentially expressed miRNAs in MII (three up- and four downregulated).

CONCLUSION(S)

We have described the FF miRNA profiles according to IVF patients' age and the maturation stage of their oocytes. This descriptive study may aid our understanding of the physiology and regulation of oocyte maturation and could identify some potential miRNA biomarkers for this process.

CLINICAL TRIAL REGISTRATION NUMBER

Not applicable.