Faculty Bibliography

OBJECTIVE: To compare telomere length (TL) and telomerase gene expression in human euploid and aneuploid blastocysts generated from IVF treatment. MATERIALS AND METHODS: TL and telomerase gene expression were measured in cryopreserved aneuploid (N=115) and euploid (N=4) human blastocysts donated by 26 patients who consented research under approval of IRB study #16-00154. Blastocysts were classified according to number of aneuploid chromosomes (A1-one segmental error, A2-one whole chromosome error, A3-two chromosomal errors and A4- >= 3 chromosomal errors). Genomic DNA and messenger RNA were separated simultaneously from individual blastocysts after thawing in vitrification-warming media. Telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC) mRNA levels were determined by RT-qPCR with GAPDH as internal control, and TL was measured by qPCR with 5s rDNA as internal control. Relative gene expression and TL were calculated by DELTADELTA^Ct method, and GraphPad Prism 8 software was used for statistical analysis.
RESULT(S): TL and telomerase gene expression were not normally distributed, so nonparametric tests were used to compare the medians among groups (Table 1). Median TL, TERTand TERC levels didn't differ by number of chromosome errors nor between aneuploid and euploid groups. Intriguingly, TL, TERT and TERC levels in aneuploid blastocysts tended to be greater compared to euploid blastocysts. TL in blastocysts correlated with telomerase TERT expression (R² =0.054, P = 0.011), but not TERC expression (R² =0.0002, P = 0.865).
CONCLUSION(S): To our knowledge, this is the largest study to measure telomere length and telomerase gene expression in human blastocysts. Our data indicated that telomeres are lengthened and telomerase is activated in aneuploid embryos at blastocyst stage. Moreover, telomere length and telomerase gene TERT in human blastocysts correlate regardless of ploidy status. Like cancer cells, TERT is highly expressed in aneuploid blastocysts. IMPACT STATEMENT: Robust TERT expression and telomere maintenance in aneuploid human blastocysts may explain why extended in vitro culture alone is insufficient to cull out aneuploidy embryos during IVF (Table Presented)

OBJECTIVE: There has been significant uncertainty surrounding the COVID-19 pandemic and its effect on human reproduction which resulted in a temporary suspension of ART treatments in early stages of the pandemic. The ACE2 receptor used by the virus to infect pulmonary cells is also found in reproductive organs and has fueled speculation as to whether the disease can be sexually transmitted and whether it can cause infertility. Non-viral issues (e.g., pandemic related psychological stress, alternate methods of communication and interaction, and new clinic procedures) may also worsen outcomes. We sought to determine whether clinical outcomes following the frozen embryo transfer (FET) of a euploid embryo were different during the COVID-19 pandemic in 2020 when compared to prior to the pandemic in 2019. MATERIALS AND METHODS: Patients who tested negative for COVID-19 and underwent FET of a single euploid embryo at NYU Fertility Center in NYC over January 2020 through September 2020 were separated by treatment month and compared with patients from the corresponding month in 2019. Patient's age at cycle start and age at freeze were compared using Student's T-Test. Potential cycle outcomes included intrauterine pregnancy (IUG), biochemical pregnancy (Biochem), and no pregnancy, and outcomes were compared between the two years using contingency Chi Square.
RESULT(S): 1,044 patients were compared over the corresponding months. 558 transfers from 2019 and 486 patients from 2020, with no patients in April of 2020. There were no differences noted in patient's age at cycle start, or age at cryopreservation, between any of the months across the two years. Analysis of outcomes following FET further revealed no statistically significant differences between any of the months over the two years, X² = 14.64, p > 0.05. Post hoc analyses comparing the combined months of March, April and May, or the combined 9-month periods, were also not statistically significant (X² = 0.042, p > 0.05; X² = 1.68, p > 0.05; respectively).
CONCLUSION(S): In patients who tested negative for COVID-19, there were no differences in treatment outcomes following FET's when comparing patients treated during the COVID pandemic with those who were treated prior to the pandemic. IMPACT STATEMENT: Providers and patients can be reassured that with proper testing and sanitizing techniques FET outcomes remained unaffected by the pandemic. (Table Presented)

OBJECTIVE: It is well known that the embryo aneuploidy rate increases with women's age [1], but the effect of age on complex chromosomal abnormality (CCA) is less clear. Here, we addressed the relationship between maternal age and CCA with a retrospective cohort study. MATERIALS AND METHODS: We reviewed results of preimplantation genetic testing (PGT) by aCGH or NGS of embryo biopsies performed in an academic IVF unit between 2010 and 2019. We excluded PGT results from single gene disorder and egg donation cycles. CCA was defined as>=3 chromosome abnormalities (whole, partial and/or mosaic). Maternal age was categorized according to SART age groups: <35, 35-37, 38-40, 41-42, and >42 years. Statistical analyses were conducted using GraphPad Prism 8.
RESULT(S): 27,423 embryos were biopsied from 3,501 women aged 23 to 48 years. 4,740 embryos (16%) has CCA. Consistent with prior study [2], the most frequent chromosomes involved in CCA were 22, 16, 21 and 15, with incidences of 30.6%, 29.1%, 26.1% and 25.8% respectively. The number of chromosomal errors (from 3 to 42) involved in CCA did not correlate with maternal age (Spearman r = -0.0149, P = 0.3352). However, the rate of complex abnormal embryos tended to increase with advancing maternal age (9.7%, 11.2%, 10.9%, 24.8% and 43.6% in women aged < 35, 35-37, 38-40, 41-42, and > 42 years, respectively). Women over 40 years old had significantly higher rates of CCA compared to those under 40 years (Chisquare test, P < 0.0001). Surprisingly, the relationship between maternal age and CCA followed a U-shaped curve, decreasing from the 25 to 30 year old group (Pearson r = -0.831, P = 0.04) to the 30 to 35 year old group (Pearson r = 0.093, P = 0.861), then increased markedly in the 35 to 48 year old group (Pearson r = 0.921, P < 0.0001).
CONCLUSION(S):We found that CCA embryos share common features of aneuploidy, such as association with maternal age and preferential involvement of shorter chromosomes i.e. 22, 16, 21 and 15. Unexpectedly, our data showed that the relationship between CCA and maternal age assumes a U shape with increased rates at very young and very old ages. Both meiotic and mitotic errors contribute to chromosomal abnormality, and the contribution of each to CCA merits further investigation. IMPACT STATEMENT: The complex relationship between maternal age and embryo aneuploidy, which approximates a U-shape, may inform optimal timing of elective oocyte freezing and oocyte donation