Ricerc@Sapienza

STUDY QUESTION: Can miRNAs be reliably detected in the spent blastocyst media (SBM) after IVF as putative biomarkers of the
implantation potential of euploid embryos?
SUMMARY ANSWER: Adjustment of the data for blastocyst quality and the day of full-expansion hinders the predictive power of a fast,
inexpensive, reproducible and user-friendly protocol based on the detection of 10 selected miRNAs from SBM.
WHAT IS KNOWN ALREADY: Euploidy represents so far the strongest predictor of blastocyst competence. Nevertheless, ∼50% of
the euploid blastocysts fail to implant. Several studies across the years have suggested that a dialogue exists between the embryo and the
endometrium aimed at the establishment of a pregnancy. MicroRNAs have been proposed as mediators of such a dialogue and investigated
in this respect. Several expensive, time-consuming and complex protocols have been adopted and promising results have been produced, but
conclusive evidence from large clinical studies is missing.
STUDY DESIGN, SIZE, DURATION: This study was conducted in two phases from September 2015 to December 2017. In Phase 1,
the human blastocyst miRNome profile was defined from the inner cell mass (ICM) and the corresponding whole-trophectoderm (TE) of six
donated blastocysts. Two different protocols were adopted to this end. In parallel, 6 pools of 10 SBM each were run (3 from only implanted
euploid blastocysts, IEBs; and 3 from only not-implanted euploid blastocysts, not-IEBs). A fast, inexpensive and user-friendly custom protocol
for miRNA SBM profiling was designed. In Phase 2, 239 SBM from IEB and not-IEB were collected at three IVF centres. After 18 SBM from
poor-quality blastocysts were excluded from the analysis, data from 107 SBM from not-IEB and 114 from IEB were produced through the
previously developed custom protocol and compared. The data were corrected through logistic regressions.
PARTICIPANT/MATERIALS, SETTINGS, METHODS: Donated blastocysts underwent ICM and whole-TE isolation. SBM were
collected during IVF cycles characterized by ICSI, blastocyst culture in a continuous media, TE biopsy without zona pellucida opening in
Day 3, quantitative PCR (qPCR)-based aneuploidy testing and vitrified-warmed single euploid embryo transfer. Not-IEB and IEB were clustered
following a negative pregnancy test and a live birth, respectively. The Taqman Low Density Array (TLDA) cards and the Exiqon microRNA
human panel I+II qPCR analysis protocols were adopted to analyse the ICM and whole-TE. The latter was used also for SBM pools. A custom
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Customized miRNA analysis in spent IVF media 1747
protocol and plate was then designed based on the Exiqon workflow, validated and finally adopted for SBM analysis in study Phase 2. This
custom protocol allows the analysis of 10 miRNAs from 10 SBM in 3 hours from sample collection to data inspection.
MAIN RESULTS AND ROLE OF THE CHANCE: The TLDA cards protocol involved a higher rate of false positive results (5.6% versus
2.8% with Exiqon). There were 44 miRNAs detected in the ICM and TE from both the protocols. One and 24 miRNAs were instead detected
solely in the ICM and the TE, respectively. Overall, 29 miRNAs were detected in the pooled SBM: 8 only from not-IEB, 8 only from IEB and 13
from both. Most of them (N = 24/29, 82.7%) were also detected previously in both the ICM and TE with the Exiqon protocol; two miRNAs
(N = 2/29, 6.9%) were previously detected only in the TE, and three (N = 3/29, 10.3%) were never detected previously. In study Phase 2,
significant differences were shown between not-IEB and IEB in terms of both miRNA detection and relative quantitation. However, when the
data were corrected for embryo morphology and day of full development (i.e. SBM collection), no significant associatio