1
|
Mousavi FS, Ahmadi E, Shirazi A, Shams-Esfandabadi N, Nazari H. The effect of chemical treatment of the sheep embryo zona pellucida on the ability of blastocysts to hatch after vitrification and warming. Vet Med Sci 2021; 8:405-410. [PMID: 34532986 PMCID: PMC8788952 DOI: 10.1002/vms3.632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND The embryo release from the zona pellucida is of prerequisites of successful implantation. OBJECTIVES Regarding the negative impact of embryo cryopreservation on the blastocysts hatchability, the aim of the present study was to investigate the effects of treating embryonic zona pellucida with pronase or acidic Tyrode's solution (ATS) before morula formation on the viability, freezability, and hatchability of vitrified-warmed resulted blastocysts. METHODS In the first experiment, the zona pellucida of 3- and 4-day-old embryos were treated with the above compounds for 30 or 45 s. Then, the competency of the treated embryos to reach to blastocyst stage and the hatchability of resulting blastocysts were investigated. In the second experiment, the cryo-survivability and hatching rate of blastocysts resulting from 3-day-old embryos treated with pronase and ATS for 30 s were tested. RESULTS In the first experiment and in contrast to the 45 s exposure, 30-s exposure of embryos to pronase or ATS did not have negative effect on the viability and development of embryos to blastocyst stage. In the second experiment, the freezability of blastocysts derived from 3-day-old embryos treated with pronase and ATS for 30 s was not different from that of the control group. However, the hatching rate of the pronase group was significantly higher than that of the control group. CONCLUSION The results of the present study showed that reducing the thickness of zona pellucida of sheep embryos with pronase had no negative effect on the developmental competency and freezability of the treated embryos and improved the hatchability of vitrified-warmed blastocysts.
Collapse
Affiliation(s)
- Fatemeh-Sadat Mousavi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran
| | - Ebrahim Ahmadi
- Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Abolfazl Shirazi
- Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran.,Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Naser Shams-Esfandabadi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran.,Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Hassan Nazari
- Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| |
Collapse
|
2
|
The effect of blastomere loss during frozen embryo transfer on the transcriptome of offspring's umbilical cord blood. Mol Biol Rep 2020; 47:8407-8417. [PMID: 33068229 DOI: 10.1007/s11033-020-05878-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 09/29/2020] [Indexed: 10/23/2022]
Abstract
Blastomere loss is a common issue during frozen-thawed embryo transfer (FET). Our previous study showed that blastomere loss was associated with an increased risk of small-for-gestational-age (SGA) neonates. The present study assessed the impact of blastomere loss during cryopreservation by comparing the mRNA profiles of umbilical cord blood of FET offspring from the prospective cohort study. Umbilical cord blood samples were collected from 48 neonates, including 12 from the loss group, 11 from the intact group, and 25 from the matched spontaneous pregnancy group. RNA-seq technology was used to compare the global gene expression profiles of the lymphocytes. Then, we used TopHat software to map the reads and quantitative real-time PCR to validate some important differentially expressed genes (DEGs). We identified 92 DEGs between the loss group and the spontaneous pregnancy group, including IGF2 and H19. Ingenuity Pathway Analysis (IPA) showed that the DEGs were most affected in the blastomere loss group. Downstream analysis also predicted the activation of organismal death pathways. In conclusions, our pilot study sheds light on the mechanism underlying how human blastomere loss may affect offspring at the gene expression level. These conclusions are, however, only suggestive, as the current study is based on a very limited sample size and type or nature of biological samples. Additional studies with larger sample sizes and independent experiments with placental samples should be conducted to verify these findings.
Collapse
|
3
|
Nagy ZP, Shapiro D, Chang CC. Vitrification of the human embryo: a more efficient and safer in vitro fertilization treatment. Fertil Steril 2020; 113:241-247. [PMID: 32106970 DOI: 10.1016/j.fertnstert.2019.12.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 01/08/2023]
Abstract
Cryopreservation has become a central pillar in assisted reproduction, reflected in the exponential increase of "freeze all" cycles in the past few years. Vitrification makes it possible to cool and warm human eggs and embryos with far less cryo-damage than 'slow-freeze' and allows nearly intact survival of embryos with very high survival rates for eggs as well. This has resulted in a complete transformation how we manage treatment for in vitro fertilization patients. Fresh transfers can be avoided without compromising outcomes, and in fact, cumulative pregnancy/delivery rates may be improved by performing sequential elective "frozen" single embryo transfers. Some recent evidence suggests that previously vitrified embryos give better perinatal outcomes than fresh embryo transfers. Frozen embryo transfer, especially when coupled with preimplantation genetic testing allows for highly efficient single embryo transfers that translate to more singleton and therefore safer pregnancies, as well as healthier babies. Additionally, vitrification has also opened new options for patients, most notably fertility preservation (through oocyte cryopreservation), and donor egg banking.
Collapse
|
4
|
Beilby K, Quinn P. Appendix F: Quinn's Advantage Embryo Freeze Kit. Methods Mol Biol 2017; 1568:343-354. [PMID: 28421510 DOI: 10.1007/978-1-4939-6828-2_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Despite a large focus on the use of vitrification to cryopreserve embryos in recent years, there are still arguments for the use of slow freezing for the cleavage-stage embryo. Having said this, there are lessons to be learned from the process of vitrification that could be applied to slow freezing to improve post-thaw survival and ultimately clinical pregnancy rates. Specifically, increasing the concentration of sucrose in the freezing solution from 0.1 to 0.2 M and subsequently increasing the sucrose concentrations in thawing solutions could prove beneficial. The use of vitrification warming solutions in the thawing of slow-frozen embryos may also be an option that not only improves survival but also streamlines product purchasing and protocols within the laboratory.
Collapse
Affiliation(s)
- Kiri Beilby
- Monash University, 3168, VIC, Melbourne, Australia.
| | - Patrick Quinn
- Quinn's IVF Consulting, 3700 S Ironwood Dr. Lot 139, Apache Junction, AZ, 85120, USA
| |
Collapse
|
5
|
Clinical outcomes of vitrified-thawed embryo transfer using a pull and cut straw method. Obstet Gynecol Sci 2013; 56:182-9. [PMID: 24327999 PMCID: PMC3784120 DOI: 10.5468/ogs.2013.56.3.182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 02/01/2013] [Accepted: 03/18/2013] [Indexed: 11/23/2022] Open
Abstract
Objective To compare the clinical outcomes of patients with vitrified-thawed embryos transferred using either the 0.25 mL straw method and the pull and cut straw (PNC) method. To evaluate the clinical outcomes of patients with transferred embryos that underwent assisted hatching at the cleaved embryo (day 3) or the blastocyst (day 5) stage. Methods The study population consisted of women who underwent vitrified-warmed embryo transfer between May 2000 and December 2011 and assisted hatching was performed after warming of embryos. Cycles of thawing between assisted hatching treated and non treated groups were compared for survival and pregnancy rates. Results The PNC vitrification method improved survival and pregnancy rates in partial lysed embryos. While assisted hatching did not affect the developmental and clinical pregnancy rates of the vitrified-warmed blastocyst group, it did increase the pregnancy rate of poor quality vitrified-warmed cleaved embryos. Conclusion These results suggest that PNC may increase the number of clinical pregnancies via the vitrification of both cleaved embryos and blastocysts. In addition, selective assisted hatching treatment of embryos that show a poor prognosis after warming may increase the rate of clinical pregnancy.
Collapse
|
6
|
Wang XL, Zhang X, Qin YQ, Hao DY, Shi HR. Outcomes of day 3 embryo transfer with vitrification using Cryoleaf: a 3-year follow-up study. J Assist Reprod Genet 2012; 29:883-9. [PMID: 22684538 DOI: 10.1007/s10815-012-9814-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Accepted: 05/28/2012] [Indexed: 10/28/2022] Open
Abstract
OBJECTIVE To compare success rates of vitrified-warmed with fresh and frozen-thawed ETs DESIGN Retrospective. SETTING Public fertility center. PATIENT(S) Cryopreserved- thawed/warmed ETs were included in this study. Fresh cycles, in which supernumerary embryos were cryopreserved, were set as the fresh control group. INTERVENTION(S) Supernumerary day 3 embryos were cryopreserved by slow-freezing or vitrification and transferred after thawing or warming. MAIN OUTCOME MEASURE(S) Comparison of two cryopreservation techniques with respect to post-thaw survival of embryos, implantation and pregnancy rates, neonatal outcome, and congenital birth defects. RESULTS A total of 962 fresh, 151 freezing-thawed and 300 vitrified-warmed cycles were included in this study. The survival and intact cell rates in the vitrification group were significantly higher compared with those in the slow freezing group (88.5 % vs 74.5 % and 86.6 % vs 64.0 %). The implantation, clinical pregnancy and live birth rates of the vitrification group were similar to the fresh and significant higher than slow freezing group. There were no significant differences in mean gestational age, birth weight, stillbirth, birth defects and the prevalence of neonatal diseases among three groups. CONCLUSION Vitrified-warmed ETs yield comparable outcomes with fresh ETs and is superior to frozen-thawed ETs regarding the survival rate and clinical outcomes.
Collapse
Affiliation(s)
- Xing-ling Wang
- Department of gynecology, the first affiliated hospital of Zhengzhou University, Zheng Zhou, China
| | | | | | | | | |
Collapse
|
7
|
Edgar DH, Gook DA. A critical appraisal of cryopreservation (slow cooling versus vitrification) of human oocytes and embryos. Hum Reprod Update 2012; 18:536-54. [PMID: 22537859 DOI: 10.1093/humupd/dms016] [Citation(s) in RCA: 215] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Vitrification is now a commonly applied technique for cryopreservation in assisted reproductive technology (ART) replacing, in many cases, conventional slow cooling methodology. This review examines evidence relevant to comparison of the two approaches applied to human oocytes and embryos at different developmental stages. METHODS Critical review of the published literature using PubMed with particular emphasis on studies which include data on survival and implantation rates, data from fresh control groups and evaluation of the two approaches in a single setting. RESULTS Slow cooling is associated with lower survival rates and compromised development relative to vitrification when applied to metaphase II (MII) oocytes, although the vitrification results have predominantly been obtained using direct contact with liquid nitrogen and there is some evidence that optimal protocols for slow cooling of MII oocytes are yet to be established. There are no prospective randomized controlled trials (RCTs) which support the use of either technique with pronuclear oocytes although vitrification has become the method of choice. Optimal slow cooling, using modifications of traditional methodology, and vitrification can result in high survival rates of early embryos, which implant at the same rate as equivalent fresh counterparts. Many studies report high survival and implantation rates following vitrification of blastocysts. Although slow cooling of blastocysts has been reported to be inferior in some studies, others comparing the two approaches in the same clinical setting have demonstrated comparable results. The variation in the extent of embryo selection applied in studies can lead to apparent differences in clinical efficiency, which may not be significant if expressed on a 'per oocyte used' basis. CONCLUSIONS Available evidence suggests that vitrification is the current method of choice when cryopreserving MII oocytes. Early cleavage stage embryos can be cryopreserved with equal success using slow cooling and vitrification. Successful blastocyst cryopreservation may be more consistently achieved with vitrification but optimal slow cooling can produce similar results. There are key limitations associated with the available evidence base, including a paucity of RCTs, limited reporting of live birth outcomes and limited reporting of detail which would allow assessment of the impact of differences in female age. While vitrification has a clear role in ART, we support continued research to establish optimal slow cooling methods which may assist in alleviating concerns over safety issues, such as storage, transport and the use of very high cryoprotectant concentrations.
Collapse
Affiliation(s)
- David H Edgar
- Reproductive Services/Melbourne IVF, Royal Women's Hospital, Parkville, Victoria 3052, Australia
| | | |
Collapse
|
8
|
Capalbo A, Rienzi L, Buccheri M, Maggiulli R, Sapienza F, Romano S, Colamaria S, Iussig B, Giuliani M, Palagiano A, Ubaldi F. The worldwide frozen embryo reservoir: methodologies to achieve optimal results. Ann N Y Acad Sci 2011; 1221:32-9. [DOI: 10.1111/j.1749-6632.2010.05931.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
9
|
Effect of laser zona thinning on vitrified–warmed embryo transfer at the cleavage stage: a prospective, randomized study. Reprod Biomed Online 2010; 20:234-42. [DOI: 10.1016/j.rbmo.2009.11.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 04/07/2009] [Accepted: 11/03/2009] [Indexed: 11/19/2022]
|
10
|
AbdelHafez FF, Desai N, Abou-Setta AM, Falcone T, Goldfarb J. Slow freezing, vitrification and ultra-rapid freezing of human embryos: a systematic review and meta-analysis. Reprod Biomed Online 2009; 20:209-22. [PMID: 20113959 DOI: 10.1016/j.rbmo.2009.11.013] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 04/16/2009] [Accepted: 09/21/2009] [Indexed: 11/26/2022]
Abstract
Embryo cryopreservation is an important aspect of assisted reproduction. Many methods have been described, but they have been poorly investigated in randomized trials, highlighting the need for a systematic review of the literature. Meticulous electronic/hand searches were performed to locate randomized trials (RCT) comparing embryo cryopreservation methods. Primary outcomes were clinical pregnancy rate (CPR) and incidence of congenital abnormalities. Secondary outcomes included live-birth (LBR), ongoing pregnancy (OPR), implantation (IR), and miscarriage (MR) rates. Data were extracted to allow for an intention-to-treat analysis and analysed using a random-effects model. Literature search revealed 11 RCT, of which five were excluded. The quality of the included studies was variable, but generally poor. There was a significantly higher CPR, OPR and IR with vitrification compared with slow freezing (odds ratio (OR)=1.55, 95% confidence interval (CI)=1.03-2.32, OR=1.82, 95% CI=1.04-3.20 and OR=1.49, 95% CI=1.03-2.15, respectively). In addition, there was a significantly lower CPR and OPR with embryo ultra-rapid freezing compared with slow freezing (OR=0.35, 95% CI=0.16-0.76 and OR=0.37, 95% CI=0.17-0.81, respectively). Vitrification is superior to slow freezing, which in turn is superior to ultra-rapid freezing. However, more well-designed and powered studies are needed to further corroborate these findings.
Collapse
Affiliation(s)
- Faten F AbdelHafez
- Department of Obstetrics and Gynecology, Cleveland Clinic Foundation, Cleveland, OH, USA
| | | | | | | | | |
Collapse
|
11
|
The number of blastomeres in post-thawing embryos affects the rates of pregnancy and delivery in freeze-embryo-transfer cycles. J Assist Reprod Genet 2009; 26:569-73. [PMID: 19898930 DOI: 10.1007/s10815-009-9360-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 10/16/2009] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To observe the differences in pregnancy rates (PRs), delivery rates, and abortion rates associated with frozen-embryo-transfer (FET)-based use of post-thawing embryos with different numbers of blastomeres. METHODS 959 FET cycles and 361 successful FET cycles performed between January 2007 and December 2007. Compare the PRs and abortion rates in post-thawing embryos with 8 blastomeres (8c), 7c, 6c, 5c, 4c,and 3c. RESULTS 1. The total PRs of post-thawing 8c, 7c, 6c, 5c, 4c, and 3c embryos were 44.1%, 41.0%, 34.4%, 23.8%, 12.5%, and 0%, respectively (p < 0.05). 2. The abortion rates for the transferred embryos of the 8c, 7c, 6c, 5c, and 4c groups were 17.92%, 19.35%, 27.69%, 24%, 20%, respectively (p < 0.05). CONCLUSION The number of blastomeres in the post-thawing embryos is an important factor influencing the occurrence of pregnancy in FET procedures; however, the criterion that post-thawing embryos with 50% intact blastomeres will lead to pregnancy may not be valid.
Collapse
|
12
|
Granne I, Child T, Hartshorne G, (on behalf of the British Fertility. Embryo cryopreservation: Evidence for practice. HUM FERTIL 2009; 11:159-72. [DOI: 10.1080/14647270802242205] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
13
|
Effect of laser-assisted hatching and necrotic blastomere removal on the development of vitrified-warmed four-cell mouse embryos. J Assist Reprod Genet 2008; 25:333-9. [PMID: 18688708 DOI: 10.1007/s10815-008-9238-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022] Open
Abstract
PURPOSE To investigate the effect of laser-assisted hatching and necrotic blastomere removal on the development of vitrified-warmed mouse embryos. METHODS The vitrified-warmed four-cell stage mouse embryos were divided into five groups; vitrified intact with no laser-assisted hatching, vitrified intact with laser-assisted hatching, vitrified damaged with neither laser assisted hatching nor necrotic blastomere removal, vitrified damaged with laser-assisted hatching, and vitrified damaged with necrotic blastomere removal. Thereafter blastocyst formation, blastomere and apoptotic cell number within all groups were statistically compared. RESULTS The rate of blastocyst formation showed a significant improvement in the group vitrified intact with laser-assisted hatching. However, neither laser-assisted hatching nor necrotic blastomere removal can improve a delayed vitrified-warmed damaged embryos in term of blastocyst formation and total cell number. Nevertheless, apoptotic cell number was significantly reduced after application of both techniques. CONCLUSIONS Laser-assisted hatching can improve the development of vitrified-warmed intact four-cell stage mouse embryos, whereas necrotic blastomere removal has no significant effect on the development of vitrified-warmed four-cell stage damaged embryos.
Collapse
|
14
|
Zheng X, Liu P, Chen G, Qiao J, Wu Y, Fan M. Viability of frozen-thawed human embryos with one-two blastomeres lysis. J Assist Reprod Genet 2008; 25:281-5. [PMID: 18607715 DOI: 10.1007/s10815-008-9224-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 04/23/2008] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVE To assess the impact of one-two blastomeres lysis on the viability of thawed day 3 human embryos. METHODS A retrospective analysis was performed on 248 frozen-thawed embryo replacement cycles in which all embryos were frozen at day 3 at the seven-eight cell stage with <or=10% fragmentation. RESULTS Outcomes of transfer cycles with fully intact embryos (intact group) were compared with those in which all transferred embryos have lost one-two blastomeres (damage group). Comparable pregnancy rates (38.46% vs 38.64%), birth rates (34.62% vs 36.36%) and implantation rates (26.31% vs 26.25%) were obtained in intact and damage groups. These results were also not significantly different from mixed transfer cycles in which one intact embryo and one damaged embryo were transferred together. CONCLUSION The developmental potential of partially damaged cryopreserved human embryos with less than 25% cells loss is comparable to that of fully intact embryos. Presence of one-two lysed blastomeres in the thawed day 3 embryo does not appear to have a negative influence on the further development of the sibling intact cells.
Collapse
Affiliation(s)
- Xiaoying Zheng
- Department of Ob & Gyn, The Third Hospital, Peking University, Beijing, China
| | | | | | | | | | | |
Collapse
|
15
|
Van de Velde H, Cauffman G, Tournaye H, Devroey P, Liebaers I. The four blastomeres of a 4-cell stage human embryo are able to develop individually into blastocysts with inner cell mass and trophectoderm. Hum Reprod 2008; 23:1742-7. [DOI: 10.1093/humrep/den190] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
16
|
Alikani M. The origins and consequences of fragmentation in mammalian eggs and embryos. HUMAN PREIMPLANTATION EMBRYO SELECTION 2007. [DOI: 10.3109/9780203089712.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
17
|
Elliott TA, Colturato LFA, Taylor TH, Wright G, Kort HI, Nagy ZP. Lysed cell removal promotes frozen–thawed embryo development. Fertil Steril 2007; 87:1444-9. [PMID: 17296186 DOI: 10.1016/j.fertnstert.2006.11.064] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Revised: 11/07/2006] [Accepted: 11/07/2006] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To develop a mouse model to investigate the possible causes for increased success rates when lysed cells are removed from thawed embryos. DESIGN Experimental study. SETTING Clinical IVF laboratory. INTERVENTION(S) Assisted hatching, cell lysis, and removal of lysed cells. MAIN OUTCOME MEASURE(S) Embryonic growth rate and morphology. RESULT(S) The mouse embryos were divided into three groups; control (no cell lysis), group 1 (cell lysis and removal), and group 2 (cell lysis only). There was no significant difference in the initial number of blastomeres in each group or the number of cells lysed artificially in groups 1 and 2. The rate of embryonic development showed a significant delay in group 2 (7.97 +/- 4.92; control, 10.42 +/- 8.18; group 1, 5.74 +/-4.42; group 2). The embryo morphology on day 4 was significantly improved in group 1 and the control group when compared with group 2. CONCLUSION(S) Mouse embryos with artificially lysed cells after thawing had poorer developmental quality and growth rates compared with control embryos. However, removal of lysed cells restored the embryo's developmental potential to that of the control. Cell number and morphology was also significantly improved compared with embryos without lysed cell removal. These findings are consistent with human embryo development after thawing when lysed cells are present and thus mechanical lysis seems to be an appropriate method by which to further study frozen-thawed lysed cell removal.
Collapse
|
18
|
Vajta G, Nagy ZP. Are programmable freezers still needed in the embryo laboratory? Review on vitrification. Reprod Biomed Online 2006; 12:779-96. [PMID: 16792858 DOI: 10.1016/s1472-6483(10)61091-7] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The predictable answer to the provocative question of whether programmable freezers are still needed in the embryo laboratory is an even more provocative 'no'. However, such a radical statement needs strong support. Based on the extensive literature of the past 5 years, the authors collected arguments either supporting or contradicting their opinion. After an overview of the causes of cryoinjuries and strategies to eliminate them, the evolution of vitrification methods is discussed. Special attention is paid to the biosafety issues. The authors did not find any circumstance in oocyte or embryo cryopreservation where slow freezing offers considerable advantages compared with vitrification. In contrast, the overwhelming majority of published data prove that the latest vitrification methods are more efficient and reliable than any version of slow freezing. Application of the proper vitrification methods increases the efficiency of long-term storage of stem cells and opens new perspectives in cryopreservation of oocytes, both for IVF and somatic cell nuclear transfer. However, lack of support from regulatory authorities, and conservative approachs regarding novel techniques can slow down the implementation of vitrification. The opinion of the authors is that vitrification is the future of cryopreservation. The public have the final say in whether they want and allow this future to arrive.
Collapse
Affiliation(s)
- Gábor Vajta
- Population Genetics and Embryology, Department of Genetics and Biotechnology, Danish Institute of Agricultural Sciences, Research Centre Foulum, DK-8830 Tjele, Denmark.
| | | |
Collapse
|