The University of Southampton
University of Southampton Institutional Repository

Incubator type affects human blastocyst formation and embryo metabolism: a randomized controlled trial

Incubator type affects human blastocyst formation and embryo metabolism: a randomized controlled trial
Incubator type affects human blastocyst formation and embryo metabolism: a randomized controlled trial

STUDY QUESTION: Does the type of incubator used to culture human preimplantation embryos affect development to the blastocyst stage and alter amino acid utilization of embryos in assisted reproduction? SUMMARY ANSWER: Culturing embryos in a time lapse system (TLS) was associated with a higher Day 5 blastocyst formation rate and altered amino acid utilization when measured from Day 3 to Day 5 compared to the standard benchtop incubator. WHAT IS KNOWN ALREADY: Culture environment is known to be important for the developing preimplantation embryo. TLSs provide a stable milieu allowing embryos to be monitored in situ, whereas embryos cultured in standard benchtop incubators experience environmental fluctuations when removed for morphological assessment. STUDY DESIGN, SIZE, DURATION: A prospective clinical trial randomizing 585 sibling embryos to either the TLS (289 embryos) or the standard benchtop incubator (296 embryos) over a 23-month period in a UK University Hospital Fertility Clinic. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were aged 42 years or under, had an antral follicle count of ≥12 and ≥6 2 pronucleate zygotes. Zygotes were cultured individually in 25 µl of medium. Randomized embryos were graded and selected for transfer or cryopreservation on Day 5. For those embryos produced by women who underwent stimulation with recombinant FSH injections and were triggered with hCG, spent medium was collected on Day 5 for amino acid analysis by high pressure liquid chromatography. Clinical pregnancy was defined as the presence of a foetal heart beat on ultrasound scan at 7 weeks. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, blastocyst formation rate on Day 5 was significantly higher in embryos cultured in the TLS (55%) compared to the standard incubator (45%; P = 0.013). Similarly, there was an increase in the number of blastocysts suitable for cryopreservation in the TLS (31%) compared to the standard incubator (23%; P = 0.032). There was a significant difference in the utilization of 12 amino acids by blastocysts cultured from Day 3 to Day 5 in the TLS compared to the standard incubator. Embryos cultured in the TLS displayed an increased total amino acid utilization (P < 0.001) and reduced amino acid production (P < 0.001) compared to those in the standard incubator. Irrespective of incubator used, embryos fertilized by ICSI depleted significantly more amino acids from the medium compared to those fertilized by conventional IVF. There was no difference in the mean score of blastocysts transferred, or the clinical pregnancy rate after transfer of embryos from either of the incubators. LIMITATIONS, REASONS FOR CAUTION: The study was not powered to discern significant effects on clinical outcomes. WIDER IMPLICATIONS OF THE FINDINGS: The metabolism and development of preimplantation embryos is impacted by the type of incubator used for culture. Further research is required to investigate the long-term implications of these findings. STUDY FUNDING/COMPETING INTEREST(S): NIHR Southampton Biomedical Research Centre Commercial and Enterprise Incubator Fund funded this study. The TLS was provided on loan for the study by Vitrolife. The authors declare no conflict of interests. TRIAL REGISTRATION NUMBER: ISRCTN73037149. TRIAL REGISTRATION DATE: 12 January 2012. DATE OF FIRST PATIENT’S ENROLMENT: 21 January 2012.

amino acid metabolism, blastocyst, culture incubator, developmental competency, time lapse
1460-2350
2757-2767
Kermack, Alexandra
b9294c93-c736-4505-abe4-78bee493f1c2
Fesenko, Irina V.
faa964d0-ed40-47c9-bc9c-930b8010aab7
Christensen, David R.G.
83abefba-97f2-4aea-b2fd-9516e3d2d99b
Parry, Kate
7180a304-dd45-4d0f-aed3-75b52d62a786
Lowen, Philippa
f2514089-dc9b-49ce-8d8b-c790cad9bf9a
Wellstead, Susan J.
26c61d1d-5c6d-425c-b5d3-c5da400a938e
Harris, Scott
19ea097b-df15-4f0f-be19-8ac42c190028
Calder, Philip
1797e54f-378e-4dcb-80a4-3e30018f07a6
Macklon, Nicholas S
7db1f4fc-a9f6-431f-a1f2-297bb8c9fb7e
Houghton, Franchesca D.
53946041-127e-45a8-9edb-bf4b3c23005f
Kermack, Alexandra
b9294c93-c736-4505-abe4-78bee493f1c2
Fesenko, Irina V.
faa964d0-ed40-47c9-bc9c-930b8010aab7
Christensen, David R.G.
83abefba-97f2-4aea-b2fd-9516e3d2d99b
Parry, Kate
7180a304-dd45-4d0f-aed3-75b52d62a786
Lowen, Philippa
f2514089-dc9b-49ce-8d8b-c790cad9bf9a
Wellstead, Susan J.
26c61d1d-5c6d-425c-b5d3-c5da400a938e
Harris, Scott
19ea097b-df15-4f0f-be19-8ac42c190028
Calder, Philip
1797e54f-378e-4dcb-80a4-3e30018f07a6
Macklon, Nicholas S
7db1f4fc-a9f6-431f-a1f2-297bb8c9fb7e
Houghton, Franchesca D.
53946041-127e-45a8-9edb-bf4b3c23005f

Kermack, Alexandra, Fesenko, Irina V., Christensen, David R.G., Parry, Kate, Lowen, Philippa, Wellstead, Susan J., Harris, Scott, Calder, Philip, Macklon, Nicholas S and Houghton, Franchesca D. (2022) Incubator type affects human blastocyst formation and embryo metabolism: a randomized controlled trial. Human Reproduction, 37 (12), 2757-2767. (doi:10.1093/humrep/deac233).

Record type: Article

Abstract

STUDY QUESTION: Does the type of incubator used to culture human preimplantation embryos affect development to the blastocyst stage and alter amino acid utilization of embryos in assisted reproduction? SUMMARY ANSWER: Culturing embryos in a time lapse system (TLS) was associated with a higher Day 5 blastocyst formation rate and altered amino acid utilization when measured from Day 3 to Day 5 compared to the standard benchtop incubator. WHAT IS KNOWN ALREADY: Culture environment is known to be important for the developing preimplantation embryo. TLSs provide a stable milieu allowing embryos to be monitored in situ, whereas embryos cultured in standard benchtop incubators experience environmental fluctuations when removed for morphological assessment. STUDY DESIGN, SIZE, DURATION: A prospective clinical trial randomizing 585 sibling embryos to either the TLS (289 embryos) or the standard benchtop incubator (296 embryos) over a 23-month period in a UK University Hospital Fertility Clinic. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were aged 42 years or under, had an antral follicle count of ≥12 and ≥6 2 pronucleate zygotes. Zygotes were cultured individually in 25 µl of medium. Randomized embryos were graded and selected for transfer or cryopreservation on Day 5. For those embryos produced by women who underwent stimulation with recombinant FSH injections and were triggered with hCG, spent medium was collected on Day 5 for amino acid analysis by high pressure liquid chromatography. Clinical pregnancy was defined as the presence of a foetal heart beat on ultrasound scan at 7 weeks. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, blastocyst formation rate on Day 5 was significantly higher in embryos cultured in the TLS (55%) compared to the standard incubator (45%; P = 0.013). Similarly, there was an increase in the number of blastocysts suitable for cryopreservation in the TLS (31%) compared to the standard incubator (23%; P = 0.032). There was a significant difference in the utilization of 12 amino acids by blastocysts cultured from Day 3 to Day 5 in the TLS compared to the standard incubator. Embryos cultured in the TLS displayed an increased total amino acid utilization (P < 0.001) and reduced amino acid production (P < 0.001) compared to those in the standard incubator. Irrespective of incubator used, embryos fertilized by ICSI depleted significantly more amino acids from the medium compared to those fertilized by conventional IVF. There was no difference in the mean score of blastocysts transferred, or the clinical pregnancy rate after transfer of embryos from either of the incubators. LIMITATIONS, REASONS FOR CAUTION: The study was not powered to discern significant effects on clinical outcomes. WIDER IMPLICATIONS OF THE FINDINGS: The metabolism and development of preimplantation embryos is impacted by the type of incubator used for culture. Further research is required to investigate the long-term implications of these findings. STUDY FUNDING/COMPETING INTEREST(S): NIHR Southampton Biomedical Research Centre Commercial and Enterprise Incubator Fund funded this study. The TLS was provided on loan for the study by Vitrolife. The authors declare no conflict of interests. TRIAL REGISTRATION NUMBER: ISRCTN73037149. TRIAL REGISTRATION DATE: 12 January 2012. DATE OF FIRST PATIENT’S ENROLMENT: 21 January 2012.

Text
HUMREP-21-1235.R2-final - Accepted Manuscript
Download (287kB)
Text
Table I 8th September - Accepted Manuscript
Download (82kB)
Text
Figure 1 8th September - Accepted Manuscript
Download (97kB)
Text
Figure 2 8th September - Accepted Manuscript
Restricted to Repository staff only
Request a copy
Text
Figure 3 8th September - Accepted Manuscript
Restricted to Repository staff only
Request a copy
Text
Figure 4 8th September - Accepted Manuscript
Restricted to Repository staff only
Request a copy
Text
deac233 - Version of Record
Available under License Other.
Download (932kB)

Show all 7 downloads.

More information

Accepted/In Press date: 5 October 2022
e-pub ahead of print date: 26 October 2022
Published date: 26 October 2022
Additional Information: Publisher Copyright: © Crown copyright 2022.
Keywords: amino acid metabolism, blastocyst, culture incubator, developmental competency, time lapse

Identifiers

Local EPrints ID: 472006
URI: http://eprints.soton.ac.uk/id/eprint/472006
ISSN: 1460-2350
PURE UUID: 05e414b4-bf9d-441c-8c24-eaf318739034
ORCID for Alexandra Kermack: ORCID iD orcid.org/0000-0002-9176-9426
ORCID for Philip Calder: ORCID iD orcid.org/0000-0002-6038-710X
ORCID for Franchesca D. Houghton: ORCID iD orcid.org/0000-0002-5167-1694

Catalogue record

Date deposited: 23 Nov 2022 17:54
Last modified: 17 Mar 2024 03:56

Export record

Altmetrics

Contributors

Author: Irina V. Fesenko
Author: David R.G. Christensen
Author: Kate Parry
Author: Philippa Lowen
Author: Susan J. Wellstead
Author: Scott Harris
Author: Philip Calder ORCID iD
Author: Nicholas S Macklon

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×