Non-invasive preimplantation genetic testing for putative mosaic blastocysts: a pilot study

Clinical outcomes of single blastocyst transfer with machine learning guided noninvasive chromosome screening grading system in infertile patients

BACKGROUND

Prospective observational studies have demonstrated that the machine learning (ML) -guided noninvasive chromosome screening (NICS) grading system, which we called the noninvasive chromosome screening-artificial intelligence (NICS-AI) grading system, can be used embryo selection. The current prospective interventional clinical study was conducted to investigate whether this NICS-AI grading system can be used as a powerful tool for embryo selection.

METHODS

Patients who visited our centre between October 2018 and December 2021 were recruited. Grade A and B embryos with a high probability of euploidy were transferred in the NICS group. The patients in the control group selected the embryos according to the traditional morphological grading. Finally, 90 patients in the NICS group and 161 patients in the control group were compared statistically for their clinical outcomes.

RESULTS

In the NICS group, the clinical pregnancy rate (70.0% vs. 54.0%, p < 0.001), the ongoing pregnancy rate (58.9% vs. 44.7%, p = 0.001), and the live birth rate (56.7% vs. 42.9%, p = 0.001) were significantly higher than those of the control group. When the female was ≥ 35 years old, the clinical pregnancy rate (67.7% vs. 32.1%, p < 0.001), ongoing pregnancy rate (56.5% vs. 25.0%, p = 0.001), and live birth rate (54.8% vs. 25.0%, p = 0.001) in the NICS group were significantly higher than those of the control group. Regardless of whether the patients had a previous record of early spontaneous abortion or not, the live birth rate of the NICS group was higher than that of the control group (61.0% vs. 46.9%; 57.9% vs. 34.8%; 33.3% vs. 0%) but the differences were not statistically significant.

CONCLUSIONS

NICS-AI was able to improve embryo utilisation rate, and the live birth rate, especially for those ≥ 35 years old, with transfer of Grade A embryos being preferred, followed by Grade B embryos. NICS-AI can be used as an effective tool for embryo selection in the future.

Approach and Management of Pregnancies with Risk Identified by Non-Invasive Prenatal Testing

This study represents our second investigation into NIPT, involving a more extensive patient cohort with a specific emphasis on the high-risk group. The high-risk group was subsequently divided into two further groups to compare confirmed cases versus unconfirmed via direct methods. The methodology encompassed the analysis of 1400 consecutive cases from a single genetic center in western Romania, where NIPT was used to assess the risk of specific fetal chromosomal abnormalities. All high-risk cases underwent validation through direct analysis of fetal cells obtained via invasive methods, including chorionic villus sampling and amniocentesis. The confirmation process utilized QF-PCR, karyotyping, and SNP-Array methods customized to each case. Results: A high risk of aneuploidy at NIPT was identified in 36 out of 1400 (2.57%) cases and confirmed in 28 cases. The study also detected an increased risk for copy number variations (CNVs) in 1% of cases, confirmed in two instances involving one large microdeletion and one large microduplication. Trisomy 21 was the exclusive anomaly where NIPT confirmed all cases with identified risk. High-risk NIPT results which were not validated by invasive methods, were classified as false positives; parents in these cases determined to continue the pregnancy. In conclusion, NIPT can serve as a screening method for all pregnancies; however, in high-risk cases, an invasive confirmation test is strongly recommended.

The Comparison of Two Whole-Genome Amplification Approaches for Noninvasive Preimplantation Genetic Testing (ni-PGT) and the Application Scenario of ni-PGT during the Fresh Cycle

Recently, noninvasive preimplantation genetic testing (ni-PGT) using degenerate oligonucleotide primer PCR (DOP-PCR) and multiple annealing and looping-based amplification cycle (MALBAC)-based whole-genome amplification (WGA) methods has demonstrated predictable results in embryo testing. However, a considerable heterogeneity of results has been reported in numerous studies on these two WGA methods. Our aim was to evaluate the current WGA method for ni-PGT while further clarifying the applicable scenarios of ni-PGT in the fresh cycle. A total of 173 embryos were tested with trophectoderm biopsy and ni-PGT. In the whole preimplantation genetic testing, the clinical concordance rates of the detection results of DOP-PCR and MALBAC with the corresponding trophectoderm biopsy results were 64.12% (84/131) and 68.99% (89/129), respectively (P = 0.405). However, in the detection of abnormal embryos, the detection efficiency of ni-PGT is significantly improved [MALBAC: 96.55% versus 68.99% (P < 0.001); and DOP-PCR: 89.09% versus 64.12% (P < 0.001)]. In addition, the diagnostic efficiency of ni-PGT in low-quality blastocysts was significantly higher than that in high-quality blastocysts [MALBAC: 95.24% versus 51.85% (P = 0.001); and DOP-PCR: 91.30% versus 48.15% (P = 0.001)]. These results contribute to further understanding ni-PGT and to clarifying its application scenario in the fresh cycle.

The embryo non-invasive pre-implantation diagnosis era: how far are we?

Advancements in assisted reproduction (AR) methodologies have allowed significant improvements in live birth rates of women who otherwise would not be able to conceive. One of the tools that allowed this improvement is the possibility of embryo selection based on genetic status, performed via preimplantation genetic testing (PGT). Even though the widespread use of PGT from TE biopsy helped to decrease the interval from the beginning of the AR intervention to pregnancy, especially in older patients, in AR, there are still many concerns about the application of this invasive methodology in all cycles. Therefore, recently, researchers started to study the use of cell free DNA (cfDNA) released by the blastocyst in its culture medium to perform PGT, in a method called non-invasive PGT (niPGT). The development of a niPGT would bring the diagnostics power of conventional PGT, but with the advantage of being potentially less harmful to the embryo. Its implementation in clinical practice, however, is under heavy discussion since there are many unknowns about the technique, such as the origin of the cfDNA or if this genetic material is a true representative of the actual ploidy status of the embryo. Available data indicates that there is high correspondence between results observed in TE biopsies and the ones observed from cfDNA, but these results are still contradictory and highly debatable. In the present review, the advantages and disadvantages of niPGT are presented and discussed in relation to tradition TE biopsy-based PGT. Furthermore, there are also presented some other possible non-invasive tools that could be applied in the selection of the best embryo, such as quantification of other molecules as quality biomarkers, or the use artificial intelligence (AI) to identify the best embryos based on morphological and/or morphokitetic parameters.

Evaluation of non-invasive gene detection in preimplantation embryos: a systematic review and meta-analysis

BACKGROUND

Genetic abnormalities in embryos are responsible for most miscarriages and repeated embryo implantation failures, so a reliable preimplantation genetic screening method is urgently needed. Non-invasive preimplantation genetic testing (niPGT) is a potential method for embryo genetic diagnosis. However, the value of its application is controversial. This meta-analysis aimed to investigate and validate the diagnostic value of niPGT in patients undergoing in vitro fertilization (IVF).

METHODS

This review used the "Preferred Reporting Items" as a systematic review and meta-analysis of the diagnostic test accuracy (PRISMA-DTA) statement. We searched PubMed, Embase, Web of Science Core Collection, and Cochrane Library up to May 2022 to retrieve non-invasive preimplantation gene detection studies. The eligible research quality was evaluated following the quality assessment study-2 system for diagnostic accuracy. The pooled receiver operator characteristic curve (SROC) and the area under SROC (AUC) were used to evaluate diagnostic performance quantitatively. Threshold effect, subgroup analysis, and meta-regression analysis were used to explore the source of heterogeneity. Deeks' funnel plots and sensitivity analyses were used to test the publication bias and stability of the meta-analysis, respectively.

FINDINGS

Twenty studies met the inclusion criteria. The pooled sensitivity, specificity, and AUC were 0.84 (95% CI 0.72-0.91), 0.85 (95% CI 0.74-0.92), and 0.91 (95% CI 0.88-0.93), respectively. Subgroup analysis showed that the spent culture medium (SCM) subgroup had higher sensitivity and lower specificity than the SCM combined with the blastocoel fluid (BF) subgroup. Subgroup analysis showed that the study sensitivity and specificity of < 100 cases were higher than those of ≥ 100. Heterogeneity (chi-square) analysis revealed that sample size might be a potential source of heterogeneity. Sensitivity analysis and Deeks' funnel plots indicated that our results were relatively robust and free from publication bias.

INTERPRETATION

The present meta-analysis indicated that the pooled sensitivity, specificity, and AUC of niPGT in preimplantation genetic testing were 0.84, 0.85, and 0.91, respectively. niPGT may have high detection accuracy and may serve as an alternative model for embryonic analysis. Additionally, by subgroup analysis, we found that BF did not improve the accuracy of niPGT in embryos. In the future, large-scale studies are needed to determine the detection value of niPGT.

Concordance of PGT for aneuploidies between blastocyst biopsies and spent blastocyst culture medium

RESEARCH QUESTION

Non-invasive preimplantation genetic testing for aneuploidies (niPGT-A) avoids the possible detrimental impact of invasive PGT-A on embryo development and clinical outcomes. Does cell-free DNA (cfDNA) from spent blastocyst culture medium (BCM) reflect embryonic chromosome status better than trophectoderm (TE) biopsy?

DESIGN

In this study, 35 donated embryos were used for research and the BCM, TE biopsy, inner cell mass (ICM) and residual blastocyst (RB) were individually picked up from these embryos. Whole genome amplification (WGA) was performed and amplified DNA was subject to next-generation sequencing. Chromosome status concordance was compared among the groups of samples.

RESULTS

The WGA success rates were 97.0% (TE biopsy), 100% (ICM), 97.0% (RB) and 88.6% (BCM). Using ICM as the gold standard, the chromosomal ploidy concordance rates for BCM, TE biopsy and RB were 58.33% (14/24), 68.75% (22/32) and 78.57% (22/28); the diagnostic concordance rates were 83.33% (20/24), 87.50% (28/32) and 92.86% (26/28); and the sex concordance rates were 92.31% (24/26), 100% (32/32) and 100% (28/28), respectively. Considering RB the gold standard, the chromosome ploidy concordance rates for BCM and TE biopsy were 61.90% (13/21) and 81.48% (22/27); the diagnostic concordance rates were 71.43% (15/21) and 88.89% (24/27); and the sex concordance rates were 91.30% (21/23) and 100% (27/27), respectively.

CONCLUSIONS

The results of niPGT-A of cfDNA of spent BCM are comparable to those of invasive PGT-A of TE biopsies. Modifications of embryo culture conditions and testing methods will help reduce maternal DNA contamination and improve the reliability of niPGT-A.

Clinical application of noninvasive chromosomal screening for elective single-blastocyst transfer in frozen-thawed cycles

BACKGROUND

The objective of this study was to explore the clinical application of noninvasive chromosomal screening (NICS) for elective single-blastocyst transfer (eSBT) in frozen-thawed cycles.

METHODS

This study retrospectively analysed the data of 212 frozen-thawed single-blastocyst transfers performed in our centre from January 2019 to July 2019. The frozen embryos were selected based on morphological grades and placed in preincubation for 6 h after warming. Then spent microdroplet culture media of frozen-thawed blastocysts were harvested and subjected to NICS. The clinical outcomes were evaluated and further stratified analysis were performed, especially different fertilization approaches.

RESULTS

The clinical pregnancy, ongoing pregnancy, and live birth rates in the euploidy group were significantly higher than those in the aneuploidy group (56.2% versus 29.4%) but were nonsignificantly different from those in the chaotic abnormal/NA embryos group (56.2% versus 60.4%). Compared with day6 (D6) blastocysts, D5 blastocysts had a nonsignificantly different euploidy rate (40.4% versus 48.1%, P = 0.320) but significantly increased clinical pregnancy (57.7% versus 22.2%, P < 0.001), ongoing pregnancy (48.1% versus 14.8%, P < 0.001), and live birth rates (48.1% versus 13.0%, P < 0.001). The percentage of chaotic abnormal/NA embryos group was significantly higher among D5 embryos than among D6 embryos (30.1% versus 11.1%, P = 0.006). The percentage of aneuploid embryos was higher among the embryos with lower morphological quality(21.5% among 'good' embryos versus 34.6% among 'fair' embryos versus 46.0% among 'poor' embryos, P = 0.013); correspondingly, the overall clinical pregnancy, ongoing pregnancy and live birth rate rates showed similar declines.

CONCLUSIONS

NICS combined with morphological assessment is an effective tool to guide frozen-thawed SBT. The optimal embryo for SBT is a 'euploid embryo with good morphology', followed sequentially by a 'chaotic abnormal/NA embryo with good morphology', 'euploid embryo with fair morphology', and 'chaotic abnormal/NA embryo with fair morphology'.

An Update on Non-invasive Approaches for Genetic Testing of the Preimplantation Embryo

Preimplantation Genetic Testing (PGT) aims to reduce the chance of an affected pregnancy or improve success in an assisted reproduction cycle. Since the first established pregnancies in 1990, methodological approaches have greatly evolved, combined with significant advances in the embryological laboratory. The application of preimplantation testing has expanded, while the accuracy and reliability of monogenic and chromosomal analysis have improved. The procedure traditionally employs an invasive approach to assess the nucleic acid content of embryos. All biopsy procedures require high technical skill, and costly equipment, and may impact both the accuracy of genetic testing and embryo viability. To overcome these limitations, many researchers have focused on the analysis of cell-free DNA (cfDNA) at the preimplantation stage, sampled either from the blastocoel or embryo culture media, to determine the genetic status of the embryo non-invasively. Studies have assessed the origin of cfDNA and its application in non-invasive testing for monogenic disease and chromosomal aneuploidies. Herein, we discuss the state-of-the-art for modern non-invasive embryonic genetic material assessment in the context of PGT. The results are difficult to integrate due to numerous methodological differences between the studies, while further work is required to assess the suitability of cfDNA analysis for clinical application.

Majority of transferred mosaic embryos developed healthy live births revealed by a preclinical study using embryonic morphology assessment and noninvasive PGT-A on cell-free DNA in blastocoel fluid

PURPOSE

This preclinical study aimed to evaluate whether using transferred mosaic embryos (primarily selected by embryonic morphology assessment (EMA) and compared by the noninvasive preimplantation genetic testing for aneuploidy (niPGT-A) on cell-free DNA in blastocoel fluid (BF)) increases the rates of clinical pregnancies (CPs) and healthy live births (HLBs) and to investigate whether niPGT-A could provide valuable genetic information for the EMA-selected transferred mosaic embryos.

METHODS

This study collected 215 blastocyst culture samples and 182 BF samples. Cell-free DNA from the BF was amplified and examined by next-generation sequencing-based niPGT-A. All 182 patients underwent EMA. However, only 147 underwent in vitro fertilization and embryo transfer, and only 113 clinical outcomes were followed up. Comprehensive chromosome screening for the chorionic villus sampling of spontaneous miscarriages and noninvasive prenatal testing for ongoing pregnancies were also performed.

RESULTS

The implantation rate was 77.55% in 147 transferred high-quality embryos selected by EMA. Among 113 CPs, 16 led to spontaneous miscarriage (14.16%), and 97 resulted in HLBs (85.84%). According to the niPGT-A results for 113 patients with clinical outcomes, 80.4% had CP (euploid, 20.54%; single aneuploid, 1.79%; mosaic chromosome aneuploid and/or segmental aneuploid, 58.04%). Of all the mosaic aneuploids, 90.76% were false positive, transforming to euploid.

CONCLUSIONS

Transferred EMA-selected embryos showed higher implantation rates. The niPGT-A of BF provided valuable genetic status ("-ploid") information, which helped reduce aneuploid-induced implantation failure and miscarriage, thereby increasing the CP and HLB rates. Additionally, majority of the transferred embryos with complex/chaotic mosaic aneuploid would likely develop HLBs.

Global Trends in Research on Cell-Free Nucleic Acids in Obstetrics and Gynecology during 2017–2021

Objectives. The objectives of this study were to identify global trends in research on cell-free deoxyribonucleic acid (cfDNA) from a bibliometric perspective and provide researchers with new research hotspots. Methods. In all, we extracted 5038 pieces of literature from PubMed and 527 articles from the Web of Science Core Collection (WoSCC) database related to cfDNA published from 1 January 2017 to 31 December 2021. For PubMed literature, we employed co-word, biclustering, and strategic diagram analysis to describe the trends in research on cfDNA in the said five years. Then, we used VOSviewer analysis for the WoSCC database to display the trends in research on cfDNA in obstetrics and gynecology during 2017–2021. Results. Strategy diagram analysis of 95 major Medical Subject Headings terms extracted from 5038 pieces of literature indicated that cfDNA sequence analysis for non-invasive prenatal and genetic testing and its application in the fields of neoplasm genetics and diagnosis is a newly emerging immature theme of cfDNA. VOSviewer analysis of 527 articles showed the global trends in research on cfDNA in obstetrics and gynecology, for example, in terms of most influential authors, institutions, countries, journals, and five research hotspots: (1) cfDNA application in prenatal screening and prenatal diagnosis, (2) cfDNA application in assisted reproductive technology, (3) cfDNA application in pre-eclampsia, DNA methylation, etc., (4) cfDNA application in placental dysfunction and fetal growth restriction, and (5) cfDNA application in fetal chromosomal abnormalities (fetal aneuploidy). Conclusions. Comprehensive visual analysis provides information regarding authors, organizations, countries/regions, journals, research hotspots, and emerging topics in the field of cfDNA for obstetrics and gynecology research. This comprehensive study could make it easier to find a partner for project development and build a network of knowledge on this emerging topic.

Association of blood pressure in the first-week of hospitalization and long-term mortality in patients with acute left ventricular myocardial infarction

BACKGROUND

Previous studies have shown that optimal blood pressure (BP) control is necessary to outcomes in patients with acute myocardial infarction (AMI). Acute left ventricular MI is a prevalent type of AMI with poor prognosis. We aimed to analyze the associations between BP control in the first 7 days of hospitalization and long-term mortality specific to patients with isolated left ventricular MI.

METHODS

A total of 3108 acute left ventricular MI patients were included in this analysis. The average BP on the first seven days of hospitalization was categorized into 10-mmHg increments. The primary and secondary outcomes were all-cause death and cardiac death, respectively. Cox models were used to assess the association of outcomes with BP during hospitalization.

RESULTS

The median length-of-stay was 7 (IQR 6-10) days. The relationship between systolic BP (SBP) or diastolic BP (DBP) followed a U-shaped curve association with outcomes. All-cause mortality was higher in patients with lower SBP (≤90 mmHg) (adjusted hazard ratios (HRs) 7.12, 95% confidence interval (CI) 3.13-16.19; p < 0.001) and DBP (<60 mmHg) (HR 1.76, 95% CI 1.14-2.71; p = 0.011) [reference: 110 < SBP ≤120 mmHg; 70 < DBP ≤ 80 mmHg], respectively. Furthermore, primary outcome was higher in patients with higher SBP (>130 mmHg) (HR 1.51, 95% CI 1.12-2.03; p = 0.007) and DBP (>80 mmHg) (HR 1.61, 95% CI 1.20-2.18; p = 0.002), respectively.

CONCLUSION

Maintaining a SBP from 90 to 130 mmHg and a DBP from 60 to 80 mmHg may be beneficial to patients with acute left ventricular MI in the long run.

Preimplantation Genetic Testing for Monogenic Conditions: Is Cell-Free DNA Testing the Next Step?

Genetic assessment of an embryo via preimplantation genetic testing (PGT) represents an important reproductive option for couples wanting to try and improve success rates from in vitro fertilisation (IVF) cycles, as well as reduce their risk of having a child born with a genetic condition. Currently, biopsy of the developing embryo prior to transfer allows genetic assessment of an embryo for either chromosome copy number (aneuploidy [PGT-A] or segmental rearrangement [PGT-SR]) or to avoid the transmission of a single gene condition (monogenic conditions [PGT-M]). However, this technology is invasive and commands considerable resources. Non-invasive PGT (niPGT) offers a potential alternate mode of embryonic analysis. Whilst the utility of niPGT-A has been recently explored, there has been limited consideration of niPGT-M as an option for couples at risk of passing on a single gene or chromosomal condition. This review examines the historical and current clinical context of preimplantation embryonic analysis for monogenic conditions, in addition to important considerations surrounding the origin and analysis of cell-free deoxyribose nucleic acid (cfDNA), whether it is sourced via blastocentesis or spent embryonic culture medium (SCM). Future capabilities of this testing modality will almost certainly be enhanced by integration of whole genome sequencing into everyday practice. In addition, the increased utilisation of reproductive carrier screening as part of standard reproductive healthcare will likely result in the identification of a larger high-risk population. As a result, stratification of limited and highly specialised reproductive genetic resources will be required. Prospective parents should continue to be made aware of the limitations of this technology, with prenatal confirmatory testing remaining an essential part of antenatal care in these patients. However, niPGT-M poses an important alternate testing modality for high-risk couples, particularly in the setting of embryos that cannot be biopsied for traditional PGT-M and as demand for this treatment continues to grow.

The "mosaic" embryo: misconceptions and misinterpretations in preimplantation genetic testing for aneuploidy

Preimplantation genetic testing for aneuploidy (PGT-A) remains one of the most controversial topics in reproductive medicine. With more than 40% of in vitro fertilization cycles in the United States reportedly involving PGT, both those in favor of and those opposed to PGT-A have significant interest in the efficacy of PGT-A. Ongoing issues include what patient population, if any, benefits from PGT-A, the true frequency of chromosomal mosaicism, whether embryonic aneuploidies self-correct, and how practitioners manage embryos designated as "mosaic." This review addresses several misconceptions and misinterpretations of data surrounding the genetic analysis and prediction of mosaicism in the preimplantation embryo.