O-211 A comparative analysis of non-invasive preimplantation genetic testing for aneuploidies using next-generation sequencing on day 5 and day 6 spent culture media versus trophectoderm
Authors: Strychalska A , Sierka W , Kokot A , Jodlowec-Lubanska N , Wroblewska U , Mermer P , Simka-Lampa K , Morawiec E , Pudelko A , Bednarska-Czerwinska A 
Published: June 2023

Abstract

Study question
Purpose of this study was to analyze concordances between trophectoderm and spent culture medium from different embryo culture length (day 5 and day 6).

Summary answer
Material collected from embryos cultured to day 6 are more suitable for non-invasive preimplantation genetic testing for aneuploidies.

What is known already
Ni-PGTA (Non-invasive Preimplantation Genetic Testing for Aneuploidy) is a relatively new testing method that analyzes spent culture medium from in vitro fertilization (IVF) embryos to determine the genetic makeup of the embryos. This non-invasive approach eliminates the need for biopsy and allows for the identification of chromosomal abnormalities such as aneuploidy. The utility of ni-PGTA is to provide an efficient, accurate, and safe method for preimplantation genetic screening. The concordance between ni-PGTA and traditional biopsy-based methods for detecting aneuploidy is high, but still further research is needed to fully evaluate its accuracy and reliability.

Study design, size, duration
The study was conducted in 2021-2022 and approved by the Institution of the Bioethical Committee operating at the Regional Medical Chamber in Krakow (No. 161/KBL/OIL/2021). Informed consent for participation in the study was obtained from all patients. A total of 130 embryos were obtained: 70 from 15 patients after 5 days of culture and 60 from 11 patients after 6 days of culture.

Participants/materials, setting, methods
Whole genome amplification of collected materials was conducted using the SurePlex Kit (Illumina, San Diego, CA, USA). The libraries was prepared using VeriSeq PGS (Illumina, San Diego, CA, USA) according to manufacturer protocol. Sequential analysis was then performed on the miSeq device (Illumina, San Diego, CA, USA). The efficiency of WGA, the concordance of chromosome status between biopsied cells and media were investigated.

Main results and the role of chance
The mean DNA concentration of WGA products from embryos for day 5 from TE was 29,6 ± 2,7 (ng/µl±SD) for SCM 23,4 ± 4,2 (ng/µl±SD) and for day 6 from TE was 29,5 ± 2,7 (ng/µl±SD) for SCM 33,4 ± 6,1 (ng/µl±SD). The mean DNA concentration of TE between day 5 and day 6 are comparable but the comparison between SCM from day 5 and 6 shows significant difference. 5 of 60 samples considered uninformative based on a Derivative Log Ratio (DLR) -DLR &gt;0.4 (TE day 6: 1 sample and SCM day 6: 4 samples) were excluded from the analysis. All samples form day 5 were informative. The overall concordance rate between the ni-PGTA for day 5 and PGTA was 39/70 (55,7%) and ni-PGTA for day 6 and PGTA was 52/55 (94,5%). Sex chromosome consistence between the ni-PGTA for day 5 and PGTA was 54/70 (55,7%) and ni-PGTA for day 6 and PGTA was 51/55 (92,7%)

Limitations, reasons for caution
Special care was taken while washing embryo before changing culture medium in order to avoid maternal contamination. Special precautions were taken to avoid losing genetic material between consecutive washing steps of TE. When Conducting ni-PGTA analysis, maternal contamination needs to be considered and results interpreted with caution.

Wider implications of the findings
The results of invasive PGT-A using TE are similar to the non-invasive method based on SCM. In addition, the best results were recorded for SCM cultured up to day 6. These results are another piece of evidence confirming utility of SCM analysis for the purpose of aneuploidy evaluation.

Trial registration number
not applicable