Antonio Capalbo1, Christian S Ottolini2, Darren K Griffin3, Filippo Maria Ubaldi4, Alan H Handyside5, Laura Rienzi4. 1. GENERA, Centers for Reproductive Medicine, Rome, Italy; GENETYX, Marostica, Italy. Electronic address: capalbo@generaroma.it. 2. The Bridge Centre, London, United Kingdom; School of Biosciences, University of Kent, Canterbury, United Kingdom. 3. School of Biosciences, University of Kent, Canterbury, United Kingdom. 4. GENERA, Centers for Reproductive Medicine, Rome, Italy; GENETYX, Marostica, Italy. 5. The Bridge Centre, London, United Kingdom; School of Biosciences, University of Kent, Canterbury, United Kingdom; Illumina, Cambridge, United Kingdom.
Abstract
OBJECTIVE: To study the effect of artificial oocyte activation (AOA) on chromosome segregation errors in the meiotic divisions. DESIGN: Prospective cohort study with historical control. SETTING: Private/academic IVF centers. PATIENT(S): Fifty-six metaphase II oocytes were donated from 12 patients who had undergone IVF between June 2008 and May 2009. INTERVENTION(S): Oocytes were activated by 40 minutes' exposure to 100 μM calcium-ionophore. The activated oocyte was tubed and analyzed by array comparative genomic hybridization and/or single-nucleotide polymorphism genotyping and maternal haplotyping (meiomapping). A control sample of embryos derived from normally fertilized oocytes was included for comparison. MAIN OUTCOME MEASURE(S): Incidence of chromosome segregation errors in artificially activated and normally fertilized oocytes in relation to pronuclear evaluation. RESULT(S): Of 49 oocytes that survived the warming procedure, thirty-nine (79.6%) activated. Most activated normally, resulting in extrusion of the second polar body and formation of a single or no pronucleus (2PB1PN: 30 of 39, 76.9%; or 2PB0PN: 5 of 39, 12.8%). Twenty-seven of these were analyzed, and 16 (59.3%) were euploid, showing no effect of AOA on meiotic segregation. Single-nucleotide polymorphism analysis of normally activated oocytes confirmed normal segregation of maternal chromosomes. No difference in the proportion of meiosis II type errors was observed between artificially activated oocytes (28.6%; 95% confidence interval 3.7%-71.0%) compared with embryos obtained from normally fertilized oocytes (44.4%; 95% confidence interval 13.7%-78.8%). The abnormally activated oocytes, with ≥2PN (4 of 39, 10.3%) were diploid, indicating a failure to coordinate telophase of meiosis II with polar body extrusion. CONCLUSION(S): From this preliminary dataset, there is no evidence that AOA causes a widespread increase in chromosome segregation errors in meiosis II. However, we recommend that it be applied selectively to patients with specific indications.
OBJECTIVE: To study the effect of artificial oocyte activation (AOA) on chromosome segregation errors in the meiotic divisions. DESIGN: Prospective cohort study with historical control. SETTING: Private/academic IVF centers. PATIENT(S): Fifty-six metaphase II oocytes were donated from 12 patients who had undergone IVF between June 2008 and May 2009. INTERVENTION(S): Oocytes were activated by 40 minutes' exposure to 100 μM calcium-ionophore. The activated oocyte was tubed and analyzed by array comparative genomic hybridization and/or single-nucleotide polymorphism genotyping and maternal haplotyping (meiomapping). A control sample of embryos derived from normally fertilized oocytes was included for comparison. MAIN OUTCOME MEASURE(S): Incidence of chromosome segregation errors in artificially activated and normally fertilized oocytes in relation to pronuclear evaluation. RESULT(S): Of 49 oocytes that survived the warming procedure, thirty-nine (79.6%) activated. Most activated normally, resulting in extrusion of the second polar body and formation of a single or no pronucleus (2PB1PN: 30 of 39, 76.9%; or 2PB0PN: 5 of 39, 12.8%). Twenty-seven of these were analyzed, and 16 (59.3%) were euploid, showing no effect of AOA on meiotic segregation. Single-nucleotide polymorphism analysis of normally activated oocytes confirmed normal segregation of maternal chromosomes. No difference in the proportion of meiosis II type errors was observed between artificially activated oocytes (28.6%; 95% confidence interval 3.7%-71.0%) compared with embryos obtained from normally fertilized oocytes (44.4%; 95% confidence interval 13.7%-78.8%). The abnormally activated oocytes, with ≥2PN (4 of 39, 10.3%) were diploid, indicating a failure to coordinate telophase of meiosis II with polar body extrusion. CONCLUSION(S): From this preliminary dataset, there is no evidence that AOA causes a widespread increase in chromosome segregation errors in meiosis II. However, we recommend that it be applied selectively to patients with specific indications.
Authors: Omar Shebl; Philip Sebastian Trautner; Sabine Enengl; Elisabeth Reiter; Christina Allerstorfer; Tamara Rechberger; Peter Oppelt; Thomas Ebner Journal: J Assist Reprod Genet Date: 2021-10-13 Impact factor: 3.412