Apoptotic Gene Expression May Impact Implantation Outcomes in Women of Advanced Maternal Age
Abstract
Background: Approximately one in six women globally experiences infertility and in vitro fertilization (IVF) is one of the many assisted reproductive technologies used to address infertility. Women of advanced maternal age (AMA) (≥35 years) are at an increased risk for a decline in ovarian reserve and oocyte competence, and consequently a decreased rate of live birth after one cycle of IVF. Current practice recommends preimplantation genetic testing for aneuploidy (PGT-A) to women of AMA to increase live birth outcomes. However, recent studies have found that conventional IVF treatment was non-inferior to PGT-A, which calls into question the efficacy of PGT-A. Thus, identifying biomarkers found in preimplantation embryos that resulted in successful implantation from AMA patients can provide further insight and establish another metric for selecting the most viable embryo for transfer and increasing future live birth outcomes.
Methods: Blastocoel fluid-conditioned media was collected from day-5 IVF-embryos that underwent PGT-A. A total of 64 IVF embryos, divided amongst four sample groups based on maternal age (AMA or under) and implantation status (positive or negative) were used. RNA was purified from the pooled blastocoel fluid samples and then cDNA was synthesized. RT-qPCR was used to assess expression of CASP3, CASP7, CASP8, and BCL2L12 levels.
Results: BCL2L12 expression is increased in pooled blastocoel-fluid conditioned media samples from IVF embryos that resulted in negative implantation for both AMA patients and those under 35 years of age. There is increased CASP8 expression in media from IVF embryos from AMA patients regardless of implantation status.
Conclusions: Data suggests BCL2L12 appears to be more highly expressed in samples resulting in negative implantation. Concurrently, increased CASP8 expression is associated with samples from AMA patients and negative implantation status in patients < 35. Both BCL2L12 and CASP8 are involved in the intrinsic and extrinsic apoptotic pathways and these findings suggest that CASP8 could be activated in preimplantation embryos as an aging response as found in AMA media samples while BCL2L12 can be a stress response increasing the likelihood of negative implantation outcomes. Further research is required to establish whether concurrent expression of CASP8 and BCL2L12 shows discernible patterns that could serve as biomarkers to optimize embryo viability selection for patients undergoing IVF treatment.
Keywords
Apoptosis, Advanced Maternal Age, In-vitro Fertilization
Apoptotic Gene Expression May Impact Implantation Outcomes in Women of Advanced Maternal Age
CLC Ballroom
Background: Approximately one in six women globally experiences infertility and in vitro fertilization (IVF) is one of the many assisted reproductive technologies used to address infertility. Women of advanced maternal age (AMA) (≥35 years) are at an increased risk for a decline in ovarian reserve and oocyte competence, and consequently a decreased rate of live birth after one cycle of IVF. Current practice recommends preimplantation genetic testing for aneuploidy (PGT-A) to women of AMA to increase live birth outcomes. However, recent studies have found that conventional IVF treatment was non-inferior to PGT-A, which calls into question the efficacy of PGT-A. Thus, identifying biomarkers found in preimplantation embryos that resulted in successful implantation from AMA patients can provide further insight and establish another metric for selecting the most viable embryo for transfer and increasing future live birth outcomes.
Methods: Blastocoel fluid-conditioned media was collected from day-5 IVF-embryos that underwent PGT-A. A total of 64 IVF embryos, divided amongst four sample groups based on maternal age (AMA or under) and implantation status (positive or negative) were used. RNA was purified from the pooled blastocoel fluid samples and then cDNA was synthesized. RT-qPCR was used to assess expression of CASP3, CASP7, CASP8, and BCL2L12 levels.
Results: BCL2L12 expression is increased in pooled blastocoel-fluid conditioned media samples from IVF embryos that resulted in negative implantation for both AMA patients and those under 35 years of age. There is increased CASP8 expression in media from IVF embryos from AMA patients regardless of implantation status.
Conclusions: Data suggests BCL2L12 appears to be more highly expressed in samples resulting in negative implantation. Concurrently, increased CASP8 expression is associated with samples from AMA patients and negative implantation status in patients < 35. Both BCL2L12 and CASP8 are involved in the intrinsic and extrinsic apoptotic pathways and these findings suggest that CASP8 could be activated in preimplantation embryos as an aging response as found in AMA media samples while BCL2L12 can be a stress response increasing the likelihood of negative implantation outcomes. Further research is required to establish whether concurrent expression of CASP8 and BCL2L12 shows discernible patterns that could serve as biomarkers to optimize embryo viability selection for patients undergoing IVF treatment.