Multi-center Study to Validate niPGT-A
| Status: | Recruiting |
|---|---|
| Conditions: | Other Indications, Women's Studies, Infertility |
| Therapuetic Areas: | Other, Reproductive |
| Healthy: | No |
| Age Range: | 20 - 44 |
| Updated: | 3/27/2019 |
| Start Date: | May 29, 2018 |
| End Date: | May 2020 |
| Contact: | Carlos Gomez, BSc MSc |
| Email: | carlos.gomez@igenomix.es |
| Phone: | +34963905310 |
A Prospective, Observational, Multi-center, International Study to Validate a Non-invasive Preimplantation Genetic Test for Embryo Aneuploidy in the Spent Culture Media (niPGT-A).
Abnormal chromosome number, or aneuploidy, is common in human embryos. It is responsible for
more than half of all miscarriages, and it is the leading cause of congenital birth defects.
Besides, it has been described that aneuploidy may also affect embryo implantation.
Therefore, selecting embryos that have the best chance of implanting and growing into a
healthy baby is one of the most important steps in the field of assisted reproduction.
Recent advances in genetic technologies, such as Next-Generation Sequencing (NGS), have
allowed aneuploidy to be detected with greater sensitivity. The application of this technique
to trophectoderm biopsies, taken from embryos before transfer to the uterus, has provided
insight into the clinical impact of chromosomal status. This process of screening embryos to
make sure they have the right number of chromosomes and to look for any structural
abnormalities in the chromosomes is called Preimplantation Genetic Testing for Aneuploidy
(PGT-A). It requires specific equipment and trained personnel that will add costs and risks,
so non-invasive techniques are sought as an alternative. These non-invasive procedures has
been explored by some groups analyzing the spent culture medium where the embryo is incubated
up to the time of transfer or freezing. In daily routine, this media is discarded after
finishing the embryo culture, but it has been reported that contains traces of embryonic
cell-free DNA (cfDNA) that can represent the genetic load of the embryo. However, at the
moment there is a high variability in results across studies, with a percentage of concordant
results between the media and the trophectoderm biopsy ranging from 3.5 to 85.7%.
Thus, the main objective of this project is to validate a new non-invasive method for PGT-A
(niPGT-A), based on improved collection and analysis of the culture media to achieve higher
rates of sensitivity and specificity and to decrease the effect of some intrinsic
difficulties such as low embryonic cfDNA input, mosaicism and maternal contamination.
more than half of all miscarriages, and it is the leading cause of congenital birth defects.
Besides, it has been described that aneuploidy may also affect embryo implantation.
Therefore, selecting embryos that have the best chance of implanting and growing into a
healthy baby is one of the most important steps in the field of assisted reproduction.
Recent advances in genetic technologies, such as Next-Generation Sequencing (NGS), have
allowed aneuploidy to be detected with greater sensitivity. The application of this technique
to trophectoderm biopsies, taken from embryos before transfer to the uterus, has provided
insight into the clinical impact of chromosomal status. This process of screening embryos to
make sure they have the right number of chromosomes and to look for any structural
abnormalities in the chromosomes is called Preimplantation Genetic Testing for Aneuploidy
(PGT-A). It requires specific equipment and trained personnel that will add costs and risks,
so non-invasive techniques are sought as an alternative. These non-invasive procedures has
been explored by some groups analyzing the spent culture medium where the embryo is incubated
up to the time of transfer or freezing. In daily routine, this media is discarded after
finishing the embryo culture, but it has been reported that contains traces of embryonic
cell-free DNA (cfDNA) that can represent the genetic load of the embryo. However, at the
moment there is a high variability in results across studies, with a percentage of concordant
results between the media and the trophectoderm biopsy ranging from 3.5 to 85.7%.
Thus, the main objective of this project is to validate a new non-invasive method for PGT-A
(niPGT-A), based on improved collection and analysis of the culture media to achieve higher
rates of sensitivity and specificity and to decrease the effect of some intrinsic
difficulties such as low embryonic cfDNA input, mosaicism and maternal contamination.
Human embryos have higher aneuploidy rates (20-80%) than other species. A considerable
proportion of these aneuploid embryos have the ability to reach the blastocyst stage.
However, depending on the aneuploidy type, some will fail to implant in the uterus, while
others will implant but will be unable to carry out early embryonic development
(miscarriage), or very rarely, result in liveborn children with specific abnormalities. It is
therefore important to identify aneuploid embryos It is important to identify embryos at risk
for aneuploid chromosomes in patients with advanced maternal age (AMA), recurrent
implantation failure (RIF) or recurrent miscarriage (RM).
The identification of aneuploidies is especially important in embryos from patients with
higher aneuploidy risk such as those with advanced maternal age (AMA), recurrent implantation
failure (RIF), or recurrent miscarriage (RM). Therefore, normal embryo morphology and
development are dependent on the chromosomal complement.
PGT-A technique analyse the full chromosome content of a single cell with high sensitivity
and specificity but requires an invasive biopsy to obtain embryonic material for the genetic
analysis. Thus, non-invasive methods to replace the existing invasive testing method would be
useful in the improvement of maternal and fetal safety.
Recently, there have been many research advances in the field of genetic testing. Cell-free
DNA (cfDNA) has been observed in spent embryo culture media. The origin of the cfDNA at the
blastocyst stage could be attributed to apoptotic events which may occur during normal
development. This has encouraged different research groups to carry out analysis spent
culture media.
Various studies were initially carried out to detect specific genes associated with monogenic
disorders (MTHFR9, HBA1/HBA210, SRY11). Recently, non-invasive PGT-A has been developed, with
highly variable results on the concordance rate (3.5%,59.1%, and 85.7%, 30.6%). The
chromosomal status of the embryo from the DNA present in the spent culture medium was
compared to the one obtained following the standard protocol using trophectoderm biopsy. The
difference in the reported results can be related to the different methodologies applied
because different amplification and detection methods -aCGH or NGS- were used. Moreover, the
concordance rates were defined differently on each study, i.e. aneuploid results in spent
culture media and trophectoderm biopsy could be considered concordant despite of showing not
the same aneuploid chromosomes.
The impact of culture conditions in the efficiency of the non-invasive approach has been
investigated by Hammond et al, (2016). They found that there was consistently a very low
level of DNA contamination (mitochondrial and nuclear DNA) in media controls, from three
different types of commercial media, that had not been exposed to embryos. The low baseline
level of DNA contamination observed is thought to originate from the protein supplement of
the culture media.
Finally, there could be influence of two relevant factors on PGT-A: contamination with
maternal DNA from granulosa cells (MCC) and mosaicism.
To improve the results of IVF (In vitro Fertilization) programs, there is a need to identify
the embryo with highest implantation potential. Embryo chromosomal analysis allows the
selection of euploid embryos, which have a higher implantation success rate.
The development of a non-invasive PGT-A protocol will improve the current methodologies used
to identify those euploid embryos avoiding the detrimental effect of the biopsy on the embryo
and decreasing the economic cost.
proportion of these aneuploid embryos have the ability to reach the blastocyst stage.
However, depending on the aneuploidy type, some will fail to implant in the uterus, while
others will implant but will be unable to carry out early embryonic development
(miscarriage), or very rarely, result in liveborn children with specific abnormalities. It is
therefore important to identify aneuploid embryos It is important to identify embryos at risk
for aneuploid chromosomes in patients with advanced maternal age (AMA), recurrent
implantation failure (RIF) or recurrent miscarriage (RM).
The identification of aneuploidies is especially important in embryos from patients with
higher aneuploidy risk such as those with advanced maternal age (AMA), recurrent implantation
failure (RIF), or recurrent miscarriage (RM). Therefore, normal embryo morphology and
development are dependent on the chromosomal complement.
PGT-A technique analyse the full chromosome content of a single cell with high sensitivity
and specificity but requires an invasive biopsy to obtain embryonic material for the genetic
analysis. Thus, non-invasive methods to replace the existing invasive testing method would be
useful in the improvement of maternal and fetal safety.
Recently, there have been many research advances in the field of genetic testing. Cell-free
DNA (cfDNA) has been observed in spent embryo culture media. The origin of the cfDNA at the
blastocyst stage could be attributed to apoptotic events which may occur during normal
development. This has encouraged different research groups to carry out analysis spent
culture media.
Various studies were initially carried out to detect specific genes associated with monogenic
disorders (MTHFR9, HBA1/HBA210, SRY11). Recently, non-invasive PGT-A has been developed, with
highly variable results on the concordance rate (3.5%,59.1%, and 85.7%, 30.6%). The
chromosomal status of the embryo from the DNA present in the spent culture medium was
compared to the one obtained following the standard protocol using trophectoderm biopsy. The
difference in the reported results can be related to the different methodologies applied
because different amplification and detection methods -aCGH or NGS- were used. Moreover, the
concordance rates were defined differently on each study, i.e. aneuploid results in spent
culture media and trophectoderm biopsy could be considered concordant despite of showing not
the same aneuploid chromosomes.
The impact of culture conditions in the efficiency of the non-invasive approach has been
investigated by Hammond et al, (2016). They found that there was consistently a very low
level of DNA contamination (mitochondrial and nuclear DNA) in media controls, from three
different types of commercial media, that had not been exposed to embryos. The low baseline
level of DNA contamination observed is thought to originate from the protein supplement of
the culture media.
Finally, there could be influence of two relevant factors on PGT-A: contamination with
maternal DNA from granulosa cells (MCC) and mosaicism.
To improve the results of IVF (In vitro Fertilization) programs, there is a need to identify
the embryo with highest implantation potential. Embryo chromosomal analysis allows the
selection of euploid embryos, which have a higher implantation success rate.
The development of a non-invasive PGT-A protocol will improve the current methodologies used
to identify those euploid embryos avoiding the detrimental effect of the biopsy on the embryo
and decreasing the economic cost.
Inclusion Criteria:
- PGT-A cases with SET for any medical indication and sign the written informed consent
form approved by the Ethic Committee / Institutional Review Board after having been
duly informed of the nature of the research and voluntarily accepted to participate in
the study.
- ICSI treatment (Intra Cytoplasmic Sperm Injection) must be done in all oocytes.
- Only cases with fresh oocytes and embryos will be included.
- Age: 20-44 years old (both included).
Exclusion Criteria:
- No embryo reaching blastocyst stage with a proper morphology for trophectoderm biopsy.
- A known abnormal karyotype in a member of the couple.
- Vitrified oocytes and embryos before blastocyst biopsy.
- Preimplantation Genetic Testing for Monogenic diseases (PGT-M) or Preimplantation
Genetic Testing for Structural Rearrangements (PGT-SR) cases excluded.
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