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Palay P, Fathi D, Fathi R. Oocyte quality evaluation: a review of engineering approaches toward clinical challenges. Biol Reprod 2023; 108:393-407. [PMID: 36495197 DOI: 10.1093/biolre/ioac219] [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] [Received: 10/10/2022] [Revised: 11/24/2022] [Accepted: 11/30/2022] [Indexed: 12/14/2022] Open
Abstract
Although assisted reproductive technology has been very successful for the treatment of infertility, its steps are still dependent on direct human opinion. An important step of assisted reproductive treatments in lab for women is choosing an oocyte that has a better quality. This step would predict which oocyte has developmental competence leading to healthy baby. Observation of the oocyte morphological quality indicators under microscope by an embryologist is the most common evaluation method of oocyte quality. Such subjective method which relies on embryologist's experience may vary and leads to misdiagnosis. An alternative solution to eliminate human misjudging in traditional methods and overcome the limitations of them is always using engineering-based procedure. In this review article, we deeply study and categorize engineering-based methods applied for the evaluation of oocyte quality. Then, the challenges in laboratories and clinics settings move forward with translational medicine perspective in mind for all those methods which had been studied were discussed. Finally, a standardized process was presented, which may help improving and focusing the research in this field. Moreover, effective suggestion techniques were introduced that are expected they would be complementary methods to accelerate future researches. The aim of this review was to create a new prospect with the engineering approaches to evaluate oocyte quality and we hope this would help infertile couples to get a baby.
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Affiliation(s)
- Peyman Palay
- Department of Electrical and Computer Engineering, Tarbiat Modares University (TMU), Tehran, Iran
| | - Davood Fathi
- Department of Electrical and Computer Engineering, Tarbiat Modares University (TMU), Tehran, Iran
| | - Rouhollah Fathi
- Department of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran
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Cryopreservation of Mammalian Oocytes: Slow Cooling and Vitrification as Successful Methods for Cryogenic Storage. Methods Mol Biol 2020. [PMID: 32797426 DOI: 10.1007/978-1-0716-0783-1_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Two basic methods for the laboratory-focused cryopreservation of mammalian oocytes are described, based on work with murine oocytes. One method uses a relatively low concentration of the cryoprotectant propanediol plus sucrose and requires controlled rate cooling equipment to achieve a slow cooling rate. This method has also produced live births from cryopreserved human oocytes. The second method, which is described here, employs a high concentration of the cryoprotectant dimethyl sulfoxide plus a low concentration of polyethylene glycol. This is a vitrification method, which involves ultra-rapid cooling by plunging standard straws into liquid nitrogen vapor, hence avoiding the need for specialized equipment, but requires technical ability to manipulate the oocytes quickly in the highly concentrated cryoprotectant solutions. Murine oocytes that have been vitrified using this technique have resulted in live births. Vitrification using other cryoprotectant mixtures is now a popular clinically accepted method for cryobanking of human oocytes.
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Stigliani S, Moretti S, Anserini P, Casciano I, Venturini PL, Scaruffi P. Storage time does not modify the gene expression profile of cryopreserved human metaphase II oocytes. Hum Reprod 2015; 30:2519-26. [PMID: 26385790 DOI: 10.1093/humrep/dev232] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/24/2015] [Indexed: 02/05/2023] Open
Abstract
STUDY QUESTION Does storage time have any impact on the transcriptome of slowly frozen cryopreserved human metaphase II (MII) oocytes? SUMMARY ANSWER The length of cryostorage has no effect on the gene expression profile of human MII oocytes. WHAT IS KNOWN ALREADY Oocyte cryopreservation is a widely used technique in IVF for storage of surplus oocytes, as well as for fertility preservation (i.e. women undergoing gonadotoxic therapies) and oocyte donation programs. Although cryopreservation has negative impacts on oocyte physiology and it is associated with decrease of transcripts, no experimental data about the effect of storage time on the oocyte molecular profile are available to date. STUDY DESIGN, SIZE, DURATION This study included 27 women, ≤38 years aged, without any ovarian pathology, undergoing IVF treatment. Surplus MII oocytes were donated after written informed consent. A total of 31 non-cryopreserved oocytes and 68 surviving slow-frozen/rapid-thawed oocytes (32 oocytes cryostored for 3 years and 36 cryostored for 6 years) were analyzed. PARTICIPANTS/MATERIALS, SETTING, METHODS Pools of ≈10 oocytes for each group were prepared. Total RNA was extracted from each pool, amplified, labeled and hybridized on oligonucleotide microarrays. Analyses were performed by R software using the limma package. MAIN RESULTS AND THE ROLE OF CHANCE Comparison of gene expression profiles between surviving thawed oocytes after 3 and 6 years of storage in liquid nitrogen found no differently expressed genes. The expression profiles of cryopreserved MII oocytes significantly differed from those of non-cryopreserved oocytes in 107 probe sets corresponding to 73 down-regulated and 29 up-regulated unique transcripts. Gene Ontology analysis by DAVID bioinformatics resource disclosed that cryopreservation deregulates genes involved in oocyte function and early embryo development, such as chromosome organization, RNA splicing and processing, cell cycle, cellular response to DNA damage and to stress, DNA repair, calcium ion binding, malate dehydrogenase activity and mitochondrial activity. Among the probes significantly up-regulated in cryopreserved oocytes, two corresponded to ovary-specific expressed large intergenic noncoding (linc)RNAs. LIMITATIONS, REASONS FOR CAUTION Data validation in a larger cohort of samples would be beneficial, although we applied stringent criteria for gene selection (fold-change >3 or <1/3 and FDR < 0.1). Further research should be undertaken to verify experimentally that the length of cryostorage has no effect on gene expression profile of vitrified/warmed MII oocytes, as well as to include in analyses 'older' frozen oocytes. WIDER IMPLICATIONS OF THE FINDINGS Confirmation that the length of storage does not alter the gene expression profile of frozen oocytes is noteworthy for the safety issue of long-term oocyte banking, i.e. fertility preservation, gamete donation. STUDY FUNDING/COMPETING INTEREST This study was supported by a grant of the Italian Ministry of Health (CCM 2012) and by Ferring Pharmaceutical company. The authors have no conflicts of interest to declare.
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Affiliation(s)
- Sara Stigliani
- U.O.S. Physiopathology of Human Reproduction, IRCCS A.O.U. San Martino-IST, Genoa, Italy
| | | | - Paola Anserini
- U.O.S. Physiopathology of Human Reproduction, IRCCS A.O.U. San Martino-IST, Genoa, Italy
| | - Ida Casciano
- U.O.S. Physiopathology of Human Reproduction, IRCCS A.O.U. San Martino-IST, Genoa, Italy
| | - Pier Luigi Venturini
- U.O.S. Physiopathology of Human Reproduction, IRCCS A.O.U. San Martino-IST, Genoa, Italy University of Genoa, Genoa, Italy
| | - Paola Scaruffi
- U.O.S. Physiopathology of Human Reproduction, IRCCS A.O.U. San Martino-IST, Genoa, Italy
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Davidson AF, Benson JD, Higgins AZ. Mathematically optimized cryoprotectant equilibration procedures for cryopreservation of human oocytes. Theor Biol Med Model 2014; 11:13. [PMID: 24649826 PMCID: PMC3994563 DOI: 10.1186/1742-4682-11-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 02/19/2014] [Indexed: 11/28/2022] Open
Abstract
Background Simple and effective cryopreservation of human oocytes would have an enormous impact on the financial and ethical constraints of human assisted reproduction. Recently, studies have demonstrated the potential for cryopreservation in an ice-free glassy state by equilibrating oocytes with high concentrations of cryoprotectants (CPAs) and rapidly cooling to liquid nitrogen temperatures. A major difficulty with this approach is that the high concentrations required for the avoidance of crystal formation (vitrification) also increase the risk of osmotic and toxic damage. We recently described a mathematical optimization approach for designing CPA equilibration procedures that avoid osmotic damage and minimize toxicity, and we presented optimized procedures for human oocytes involving continuous changes in solution composition. Methods Here we adapt and refine our previous algorithm to predict piecewise-constant changes in extracellular solution concentrations in order to make the predicted procedures easier to implement. Importantly, we investigate the effects of using alternate equilibration endpoints on predicted protocol toxicity. Finally, we compare the resulting procedures to previously described experimental methods, as well as mathematically optimized procedures involving continuous changes in solution composition. Results For equilibration with CPA, our algorithm predicts an optimal first step consisting of exposure to a solution containing only water and CPA. This is predicted to cause the cells to initially shrink and then swell to the maximum cell volume limit. To reach the target intracellular CPA concentration, the cells are then induced to shrink to the minimum cell volume limit by exposure to a high CPA concentration. For post-thaw equilibration to remove CPA, the optimal procedures involve exposure to CPA-free solutions that are predicted to cause swelling to the maximum volume limit. The toxicity associated with these procedures is predicted to be much less than that of conventional procedures and comparable to that of the corresponding procedures with continuous changes in solution composition. Conclusions The piecewise-constant procedures described in this study are experimentally facile and are predicted to be less toxic than conventional procedures for human oocyte cryopreservation. Moreover, the mathematical optimization approach described here will facilitate the design of cryopreservation procedures for other cell types.
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Affiliation(s)
| | | | - Adam Z Higgins
- School of Chemical, Biological and Environmental Engineering, Oregon State University, 102 Gleeson Hall, Corvallis, Oregon 97331-2702, USA.
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Karlsson JOM, Szurek EA, Higgins AZ, Lee SR, Eroglu A. Optimization of cryoprotectant loading into murine and human oocytes. Cryobiology 2013; 68:18-28. [PMID: 24246951 DOI: 10.1016/j.cryobiol.2013.11.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 11/07/2013] [Accepted: 11/07/2013] [Indexed: 11/28/2022]
Abstract
Loading of cryoprotectants into oocytes is an important step of the cryopreservation process, in which the cells are exposed to potentially damaging osmotic stresses and chemical toxicity. Thus, we investigated the use of physics-based mathematical optimization to guide design of cryoprotectant loading methods for mouse and human oocytes. We first examined loading of 1.5 M dimethyl sulfoxide (Me(2)SO) into mouse oocytes at 23°C. Conventional one-step loading resulted in rates of fertilization (34%) and embryonic development (60%) that were significantly lower than those of untreated controls (95% and 94%, respectively). In contrast, the mathematically optimized two-step method yielded much higher rates of fertilization (85%) and development (87%). To examine the causes for oocyte damage, we performed experiments to separate the effects of cell shrinkage and Me(2)SO exposure time, revealing that neither shrinkage nor Me(2)SO exposure single-handedly impairs the fertilization and development rates. Thus, damage during one-step Me(2)SO addition appears to result from interactions between the effects of Me(2)SO toxicity and osmotic stress. We also investigated Me(2)SO loading into mouse oocytes at 30°C. At this temperature, fertilization rates were again lower after one-step loading (8%) in comparison to mathematically optimized two-step loading (86%) and untreated controls (96%). Furthermore, our computer algorithm generated an effective strategy for reducing Me(2)SO exposure time, using hypotonic diluents for cryoprotectant solutions. With this technique, 1.5 M Me(2)SO was successfully loaded in only 2.5 min, with 92% fertilizability. Based on these promising results, we propose new methods to load cryoprotectants into human oocytes, designed using our mathematical optimization approach.
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Affiliation(s)
- Jens O M Karlsson
- Department of Mechanical Engineering, Villanova University, Villanova, PA 19085, USA
| | - Edyta A Szurek
- Institute of Molecular Medicine and Genetics, Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Adam Z Higgins
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - Sang R Lee
- Institute of Molecular Medicine and Genetics, Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA
| | - Ali Eroglu
- Institute of Molecular Medicine and Genetics, Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA; Department of Obstetrics and Gynecology, and Cancer Center, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA.
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The Alpha consensus meeting on cryopreservation key performance indicators and benchmarks: proceedings of an expert meeting. Reprod Biomed Online 2012; 25:146-67. [DOI: 10.1016/j.rbmo.2012.05.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 05/11/2012] [Accepted: 05/17/2012] [Indexed: 11/20/2022]
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Oocyte slow freezing using a 0.2-0.3 M sucrose concentration protocol: is it really the time to trash the cryopreservation machine? Fertil Steril 2012; 97:1101-7. [PMID: 22365380 DOI: 10.1016/j.fertnstert.2012.01.127] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 01/27/2012] [Accepted: 01/27/2012] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To update results on outcomes with frozen/thawed oocytes using a differential sucrose concentration during dehydration (0.2 M) and rehydration (0.3 M), combined with a one-step propanediol exposure. DESIGN Retrospective cohort study. SETTING Private IVF centers. PATIENT(S) Infertile couples undergoing IVF treatment. INTERVENTION(S) Oocyte thawing cycles between May 2004 and December 2010. MAIN OUTCOME MEASURE(S) Survival, fertilization, and cleavage rates were reported to evaluate biological outcomes. Clinical pregnancy and implantation rates were analyzed as markers of efficiency. RESULT(S) Three hundred forty-two patients and 443 cycles were monitored; the survival was 71.8%, fertilization 77.9%, and of the embryos obtained 83.8% were classified as grade 1 and 2. Three hundred ninety-four transfers were performed, resulting in 90 pregnancies. The pregnancy rate per transfer was 22.8% and per patient was 26.3%, with 122 gestational sacs. The implantation rate per embryo was 13.5%. Patients were divided into three groups according to their age: ≤ 34 years (group A), 35-38 years (group B), and ≥ 39 years (group C). Biological outcomes were comparable in all three groups, whereas the pregnancy rate per transfer was higher in the first group (27.7% vs. 21.4% and 17.6%). The implantation rates per injected egg were 11.8%, 8.0%, and 7.5% for the three groups, respectively. CONCLUSION(S) The biological and clinical data obtained on 443 cycles are consistent with our previous results showing that slow freezing of oocytes can be a valid tool in IVF practice when performed with a suitable protocol.
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Tharasanit T, Manee-In S, Buarpung S, Chatdarong K, Lohachit C, Techakumphu M. Successful pregnancy following transfer of feline embryos derived from vitrified immature cat oocytes using ‘stepwise’ cryoprotectant exposure technique. Theriogenology 2011; 76:1442-9. [DOI: 10.1016/j.theriogenology.2011.06.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 06/09/2011] [Accepted: 06/13/2011] [Indexed: 10/17/2022]
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De Santis L, Coticchio G. Reprint of: Theoretical and experimental basis of slow freezing. Reprod Biomed Online 2011; 23:290-7. [PMID: 21889729 DOI: 10.1016/j.rbmo.2011.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/14/2010] [Accepted: 10/19/2010] [Indexed: 11/17/2022]
Abstract
In human IVF, cryopreservation of oocytes has become an alternative to embryo storage. It has also shown enormous potential for oocyte donation, fertility preservation and animal biotechnology. Mouse oocytes have represented the elective model to develop oocyte cryopreservation in the human and over several decades their use has made possible the development of theoretical and empirical approaches. Progress in vitrification has overshadowed slow freezing to such an extent that it has been suggested that vitrification could soon become the exclusive cryopreservation choice in human IVF. However, recent studies have clearly indicated that human embryo slow freezing, a practice considered well established for decades, can be significantly improved by a simple empirical approach. Alternatively, recent and more advanced theoretical models can predict oocyte responses to the diverse factors characterizing an entire slow-freezing procedure, offering a global method for the improvement of current protocols. This gives credit to the notion that oocyte slow freezing still has considerable margins for improvement. In human IVF, cryopreservation of oocytes has become an alternative to embryo storage. It has also shown enormous potential for oocyte donation, fertility preservation and animal biotechnology. Mouse oocytes have represented the elective model to develop oocyte cryopreservation in the human and over several decades their use has made possible the development of theoretical and empirical approaches. Progress in vitrification has overshadowed slow freezing to such an extent that it has been suggested that vitrification could soon become the exclusive cryopreservation choice in human IVF. However, recent studies have clearly indicated that human embryo slow freezing, a practice considered well established for decades, can be significantly improved by a simple empirical approach. Alternatively, recent and more advanced theoretical models can predict oocyte responses to the diverse factors characterizing an entire slow freezing procedure, offering a global method for the improvement of current protocols. This gives credit to the notion that oocyte slow freezing still has considerable margins of improvement.
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Affiliation(s)
- Lucia De Santis
- IVF Unit, Dept. Ob/Gyn, H S. Raffaele, Vita-Salute University, Milan, Italy
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Theoretical and experimental basis of slow freezing. Reprod Biomed Online 2011; 22:125-32. [DOI: 10.1016/j.rbmo.2010.10.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/14/2010] [Accepted: 10/19/2010] [Indexed: 11/22/2022]
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Chamayou S, Bonaventura G, Alecci C, Tibullo D, Di Raimondo F, Guglielmino A, Barcellona ML. Consequences of metaphase II oocyte cryopreservation on mRNA content. Cryobiology 2011; 62:130-4. [PMID: 21272569 DOI: 10.1016/j.cryobiol.2011.01.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 12/17/2010] [Accepted: 01/19/2011] [Indexed: 11/19/2022]
Abstract
INTRODUCTION We studied the consequences of freezing/thawing processes on mRNA contents in MII oocytes after slow-freezing/rapid thawing (SF/RT) and vitrification/warming (V/W) protocols, and compared the results to fresh MII oocytes. We quantified the nuclear transcript mRNA responsible for the translation of proteins belonging either to trans-regulatory protein family or to functional structural proteins such as proteins involved in DNA structural organization (NAP1L1, TOP1, H1F0H1), chromosomal structure maintenance (SMC, SCC3, RAD21, SMC1A, SMC1B, STAG3, REC8), mitochondrial energetic pathways (ATP5GJ, SDHC), cell cycle regulation and processes (CLTA, MAPK6, CKS2) and staminal cell potency-development competence stage (DPPA3, OCT4, FOXJ2). MATERIAL AND METHODS Surplus MII oocytes were donated from patients in IVF cycles and divided in three groups of 15 oocytes. Group 1 was comprised of non-cryopreserved oocytes and Groups 2 and 3 underwent SF/RT and V/W procedures, respectively. RESULTS There was an overall decrease of mRNA extracted from cryopreserved oocytes compared to control group. Only 39.4% of mRNA content were preserved after SF/RT while 63.3% of mRNA content were maintained after V/W. CONCLUSIONS Oocyte cryopreservation is associated with molecular injury associated with the decrease of stored mRNA. However the V/W protocol is more conservative than SF/RT resulting in a level of mRNA sufficient to maintain biologic functions in the subsequent fertilized oocyte.
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Affiliation(s)
- S Chamayou
- Unità di Medicina della Riproduzione--Fondazione Hera, Via Barriera del Bosco n. 51/53, Sant'Agata Li Battiali (CT), Italy.
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Coticchio G, Borini A, Distratis V, Maione M, Scaravelli G, Bianchi V, Macchiarelli G, Nottola SA. Qualitative and morphometric analysis of the ultrastructure of human oocytes cryopreserved by two alternative slow cooling protocols. J Assist Reprod Genet 2010; 27:131-40. [PMID: 20177770 DOI: 10.1007/s10815-010-9394-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 01/26/2010] [Indexed: 10/19/2022] Open
Abstract
PURPOSE To ascertain possible cell damage from cryopreservation, the ultrastructure of human oocytes cryopreserved by slow cooling was assessed. MATERIALS AND METHODS Cryopreservation was performed through two protocols with one-step or two-step propanediol. Fresh control oocytes were examined for comparison. Samples were processed for transmission electron microscopy analysis. RESULTS By light microscopy, both fresh and frozen-thawed oocytes appeared regularly rounded, with intact zona pellucida, and homogeneous cytoplasm. By electron microscopy observation, organelles were abundant and uniformly dispersed. Mitochondria-smooth endoplasmic reticulum associations appeared regular. However, both the amount and density of cortical granules appeared abnormally reduced in frozen-thawed samples. Slight to moderate vacuolization was also found in the ooplasm of oocytes of both frozen groups. CONCLUSIONS Slow cooling ensures a good overall preservation of human oocytes. However, cytoplasmic vacuolization and cortical granule loss appears associated with cryopreservation, irrespective of the protocol used.
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Borini A, Levi Setti PE, Anserini P, De Luca R, De Santis L, Porcu E, La Sala GB, Ferraretti A, Bartolotti T, Coticchio G, Scaravelli G. Multicenter observational study on slow-cooling oocyte cryopreservation: clinical outcome. Fertil Steril 2010; 94:1662-8. [PMID: 20047739 DOI: 10.1016/j.fertnstert.2009.10.029] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 10/14/2009] [Accepted: 10/19/2009] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To evaluate the efficacy of oocyte cryopreservation by a single slow-cooling protocol involving sucrose (0.2 mol/L) in the freezing solution. DESIGN Observational comparison of the clinical outcome in fresh and frozen thawed cycles. SETTING Public and private IVF centers. PATIENT(S) Infertile couples undergoing IVF treatment. INTERVENTION(S) Use of a maximum three oocytes in fresh cycles, as established by local law, and cryopreservation and later use of surplus oocytes. Likewise fresh cycles, maximum three thawed oocytes were used per cycle. All thawed oocytes were microinjected. MAIN OUTCOME MEASURE(S) Embryologic and clinical parameters of fresh and thawed cycles. RESULT(S) Two thousand forty-six patients underwent 2,209 oocyte retrievals involving oocyte cryopreservation. Overall, the survival rate of thawed oocytes was 55.8%. In 940 thaw cycles, the mean numbers of inseminated oocytes and fertilization rates were significantly decreased vs. fresh cycles outcomes (2.6 ± 0.7 vs. 2.9 ± 0.2 and 72.5% vs. 78.3%, respectively), as were the rates of implantation (10.1% vs. 15.4%), pregnancy rates per transfer (17.0% vs. 27.9%), and pregnancy rates per cycle (13.7% vs. 26.2%). Differences in clinical outcome were found among centers. A pregnancy rate per thawing cycle above 14% was achieved by most clinics. Fifty-seven retrievals involving oocyte cryopreservation achieved a pregnancy after fresh embryo replacement. Implantation and pregnancy rates per embryo transfer and per thawing cycles were 17.5%, 28.6%, and 24.6%, respectively. CONCLUSION(S) Under the conditions tested, the clinical outcome of oocyte slow-cooling cryopreservation is reduced compared with fresh cycles. Nevertheless, in cases of inapplicability of embryo cryopreservation, oocyte cryopreservation should be offered to patients with surplus oocytes.
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Affiliation(s)
- Andrea Borini
- Tecnobios Procreazione, Centre for Reproductive Health, Bologna, Italy.
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Cutting R, Barlow S, Anderson R, On Behalf of ACE and BFS. Human oocyte cryopreservation: Evidence for practice. HUM FERTIL 2009; 12:125-36. [DOI: 10.1080/14647270903132115] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Noyes N, Porcu E, Borini A. Over 900 oocyte cryopreservation babies born with no apparent increase in congenital anomalies. Reprod Biomed Online 2009; 18:769-76. [PMID: 19490780 DOI: 10.1016/s1472-6483(10)60025-9] [Citation(s) in RCA: 299] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Over the past decade, the number of reported live births resulting from oocyte cryopreservation has rapidly increased. To appreciate the true number of children born, verified live births were tabulated and assessed. A literature search was performed; authors were then contacted to verify birth outcomes and provide updates. A database including all verified live born infants was constructed. A total of 58 reports (1986-2008) were reviewed, which included 609 live born babies (308 from slow freezing, 289 from vitrification and 12 from both methods). Additionally, 327 other live births were verified. Of the total 936 live borns, 1.3% (12) were noted to have birth anomalies: three ventricular septal defects, one choanal and one biliary atresia, one Rubinstein-Taybi syndrome, one Arnold-Chiari syndrome, one cleft palate, three clubfoot and one skin haemangioma. Compared with congenital anomalies occurring in naturally conceived infants, no difference was noted. With more live born data accumulating, this procedure may become mainstream as a fertility preservation option, particularly for women diagnosed with malignancy requiring cytotoxic therapy. A registry would help to assure the safest, most expeditious development of this technology.
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Affiliation(s)
- N Noyes
- Department of Obstetrics and Gynecology, NYU Fertility Center, NYU School of Medicine, New York 10016, USA.
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Konc J, Kanyo K, Varga E, Kriston R, Cseh S. Births Resulting from Oocyte Cryopreservation Using a Slow Freezing Protocol with Propanediol and Sucrose. Syst Biol Reprod Med 2009; 54:205-10. [DOI: 10.1080/19396360802415778] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Greco E, Litwicka K, Ferrero S, Sapienza F, Minasi MG, Iacobelli M, Zavaglia D, Nagy ZP. Co-transfer of embryos derived from cryopreserved and fresh natural cycle oocytes: a pilot study. Reprod Biomed Online 2008; 17:530-6. [PMID: 18854108 DOI: 10.1016/s1472-6483(10)60241-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Italian legislation regarding reproductive medicine prohibits embryo storage while allowing cryopreservation of supernumerary oocytes. This study evaluated the effect of fresh oocytes obtained from natural unstimulated cycles on the clinical success rates derived from the use of frozen-thawed (FR-TH) oocytes obtained following ovarian stimulation. For 36 women, intracytoplasmic sperm injection was performed on FR-TH oocytes supplemented by a fresh oocyte, if available, derived from a natural cycle in which gonadotrophin-releasing hormone-antagonist was used for premature LH surge control. The retrieval rate of fresh oocytes was 61.1% and survival rate of FR-TH oocytes was 43.6%. The fertilization rate of fresh and FR-TH oocytes was 70% and 52.5%, respectively. Fifty embryos were transferred, 14 of them developed from fresh oocytes and 36 from FR-TH oocytes. Six pregnancies occurred in 10 cycles in which the embryos developed from fresh and FR-TH oocytes (pregnancy rate 60.0%) and two in 12 patients in whom the embryos were obtained from only FR-TH oocytes (pregnancy rate 16.7%) (P < 0.05). In summary, the data demonstrate that the transfer of embryos derived from oocytes cryopreserved following a previous ovarian stimulation and an embryo developed from a fresh one retrieved in natural cycle ensures an excellent clinical outcome.
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Affiliation(s)
- E Greco
- Assisted Reproduction Centre, European Hospital, Rome, Italy.
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Abstract
The main advantage of freezing oocytes is preserving the future fertility of women whose ovarian function is threatened by medical or surgical treatments and facilitating oocyte donation. The results of slow freezing of oocytes seem relatively dependent on the protocols used, most particularly on the sucrose concentration in the solutions of cryoprotective agents used. Today it seems that the use of low or medium-level concentrations of sucrose during the freezing process gives better results in terms of pregnancies and implantation than higher concentrations (0.3 mol/l), despite the sometimes less favorable results on oocyte survival after thawing. The cumulated pregnancy rates from frozen/thawed oocyte transfer are nearly equivalent to the results observed with frozen/thawed embryo transfer, which makes oocyte cryopreservation a valid alternative to embryo cryopreservation. Moreover, it seems that these results can be improved by the vitrification technique.
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Affiliation(s)
- A Borini
- Tecnobios Procreazione, Bologna, Italy.
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20
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Leibo S. Cryopreservation of oocytes and embryos: Optimization by theoretical versus empirical analysis. Theriogenology 2008; 69:37-47. [DOI: 10.1016/j.theriogenology.2007.10.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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21
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Nottola SA, Coticchio G, De Santis L, Macchiarelli G, Maione M, Bianchi S, Iaccarino M, Flamigni C, Borini A. Ultrastructure of human mature oocytes after slow cooling cryopreservation with ethylene glycol. Reprod Biomed Online 2008; 17:368-77. [DOI: 10.1016/s1472-6483(10)60220-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Cobo A, Pérez S, De los Santos MJ, Zulategui J, Domingo J, Remohí J. Effect of different cryopreservation protocols on the metaphase II spindle in human oocytes. Reprod Biomed Online 2008; 17:350-9. [DOI: 10.1016/s1472-6483(10)60218-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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23
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Mullen SF, Rosenbaum M, Critser JK. The effect of osmotic stress on the cell volume, metaphase II spindle and developmental potential of in vitro matured porcine oocytes. Cryobiology 2007; 54:281-9. [PMID: 17485076 PMCID: PMC1989776 DOI: 10.1016/j.cryobiol.2007.03.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 03/28/2007] [Accepted: 03/29/2007] [Indexed: 11/22/2022]
Abstract
Porcine animal models are used to advance our understanding of human physiology. Current research is also directed at methods to produce transgenic pigs. Cryobanking gametes and embryos can facilitate the preservation of valuable genotypes, yet cryopreserving oocytes from pigs has proven very challenging. The current study was designed to understand the effects of anisotonic solutions on in vitro matured porcine oocytes as a first step toward designing improved cryopreservation procedures. We hypothesized that the proportion of oocytes demonstrating a normal spindle apparatus and in vitro developmental potential would be proportional to the solution osmolality. Oocytes were incubated for 10 min at 38 degrees C in various hypo- or hypertonic solutions, and an isotonic control solution and then assessed for these two parameters. Our results support the hypothesis, with an increasing proportion of spindles showing a disrupted structure as the levels of anisotonic exposure diverge from isotonic. Only about half of the oocytes maintained developmental potential after exposure to anisotonic solutions compared to untreated controls. Oocyte volume displayed a linear response to anisotonic solutions as expected, with an estimated relative osmotically inactive cell volume of 0.178. The results from this study provide initial biophysical data to characterize porcine oocytes. The results from future experiments designed to determine the membrane permeability to various cryoprotectants will allow predictive modeling of optimal cryopreservation parameters and provide a basis for designing improved cryopreservation procedures.
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Affiliation(s)
- S F Mullen
- The Comparative Medicine Center and Department of Veterinary Pathobiology, The University of Missouri at Columbia, Columbia, MO 65211, USA
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24
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Kardak A, Leibo SP, Devireddy R. Membrane Transport Properties of Equine and Macaque Ovarian Tissues Frozen in Mixtures of Dimethylsulfoxide and Ethylene Glycol. J Biomech Eng 2007; 129:688-94. [PMID: 17887894 DOI: 10.1115/1.2768107] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The rate at which equine and macaque ovarian tissue sections are first cooled from +25°Cto+4°C has a significant effect on the measured water transport when the tissues are subsequently frozen in 0.85M solutions of glycerol, dimethylsulfoxide (DMSO), or ethylene glycol (EG). To determine whether the response of ovarian tissues is altered if they are suspended in mixtures of cryoprotective agents (CPAs), rather than in solutions of a single CPA, we have now measured the subzero water transport from ovarian tissues that were suspended in mixtures of DMSO and EG. Sections of freshly collected equine and macaque ovaries were suspended either in a mixture of 0.9M EG plus 0.7M DMSO (equivalent to a mixture of ∼5%v∕v of EG and DMSO) or in a 1.6M solution of only DMSO or only EG. The tissue sections were cooled from +25°Cto+4°C and then frozen to subzero temperatures at 5°C∕min. As the tissues were being frozen, a shape-independent differential scanning calorimeter technique was used to measure water loss from the tissues and, consequently, the best fit membrane permeability parameters (Lpg and ELp) of ovarian tissues during freezing. In the mixture of DMSO+EG, the respective values of Lpg and ELp for equine tissue first cooled at 40°C∕min between +25°C and +4°C before being frozen were 0.15μm∕minatm and 7.6kcal∕mole. The corresponding Lpg and ELp values for equine tissue suspended in 1.6M DMSO were 0.12μm∕minatm and 27.2kcal∕mole; in 1.6M EG, the values were 0.06μm∕minatm and 21.9kcal∕mole, respectively. For macaque ovarian tissues suspended in the mixture of DMSO+EG, the respective values of Lpg and ELp were 0.26μm∕minatm and 26.2kcal∕mole. Similarly, the corresponding LLg and ELp values for macaque tissue suspended in 1.6M DMSO were 0.22μm∕minatm and 31.4kcal∕mole; in 1.6M EG, the values were 0.20μm∕minatm and 27.9kcal∕mole. The parameters for both equine and macaque tissue samples suspended in the DMSO+EG mixture and first cooled at 0.5°C∕min between +25°C and +4°C were very similar to the corresponding values for samples cooled at 40°C∕min. In contrast, the membrane parameters of equine and macaque samples first cooled at 0.5°C∕min in single-component solutions were significantly different from the corresponding values for samples cooled at 40°C∕min. These results show that the membrane properties of ovarian cells from two species are different, and that the membrane properties are significantly affected both by the solution in which the tissue is suspended and by the rate at which the tissue is cooled from +25°Cto+4°C before being frozen. These observations suggest that these variables ought to be considered in the derivation of methods to cryopreserve ovarian tissues.
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Affiliation(s)
- A Kardak
- Bioengineering Laboratory, Department of Mechanical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Abstract
Two methods for the cryopreservation of mammalian oocytes are described. One method uses a relatively low concentration of the cryoprotectant propanediol plus sucrose and requires controlled-rate cooling equipment to achieve a slow cooling rate. Such a method has produced live births from cryopreserved human oocytes. The second method described employs a high concentration of the cryoprotectant dimethyl sulfoxide plus a low concentration of polyethylene glycol. This method involves cooling by plunging standard straws into liquid nitrogen vapor, hence avoiding the need for specialized equipment, but requires technical ability to manipulate the oocytes quickly in the highly concentrated cryoprotectant solutions. Murine oocytes vitrified, using this technique, have resulted in live births.
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Affiliation(s)
- Sharon J Paynter
- Department of Obstetrics and Gynaecology, Wales College of Medicine, Cardiff University, UK
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Bianchi V, Coticchio G, Distratis V, Di Giusto N, Flamigni C, Borini A. Differential sucrose concentration during dehydration (0.2 mol/l) and rehydration (0.3 mol/l) increases the implantation rate of frozen human oocytes. Reprod Biomed Online 2007; 14:64-71. [PMID: 17207333 DOI: 10.1016/s1472-6483(10)60765-1] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Novel protocols have increased survival and fertilization rates of cryopreserved oocytes. Nevertheless, in most cases clinical experiences have been disappointing or contradictory. Human oocytes of 141 patients were cryopreserved using a modified slow-cooling protocol involving 1.5 mol/l propane-1,2-diol (PrOH) and 0.2 mol/l sucrose during dehydration, while rehydration was conducted applying decreasing concentrations of PrOH and 0.3 mol/l sucrose. One thousand and eighty-three oocytes were frozen and 403 were thawed, with a survival rate of 75.9%. Among the 306 surviving oocytes, 252 were microinjected and 192 (76.2%) showed two pronuclei. One hundred and eighty zygotes (93.8%) cleaved. The proportion of good quality embryos (grade I and II) was 86.2%. All embryos were transferred and 17 clinical pregnancies were obtained. Pregnancy rates were 21.3% per transfer, 21.8% per patient, and 18.9% per thawing cycle. The implantation rate was 13.5% while the miscarriage rate was 11.8%. To date, four babies have been delivered, while the remaining pregnancies are ongoing. Increased oocyte survival rates can be achieved by moderately high sucrose concentrations in the freezing and thawing solutions. This also ensures elevated success rates in terms of fertilization, embryo development and clinical outcome.
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Affiliation(s)
- V Bianchi
- Tecnobios Procreazione, Via Dante 15, 40125 Bologna, Italy
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Coticchio G, Bonu MA, Sciajno R, Sereni E, Bianchi V, Borini A. Truths and myths of oocyte sensitivity to controlled rate freezing. Reprod Biomed Online 2007; 15:24-30. [PMID: 17623530 DOI: 10.1016/s1472-6483(10)60687-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The mammalian oocyte is especially sensitive to cryopreservation. Because of its size and physiology, it can easily undergo cell death or sub-lethal damage as a consequence of intracellular ice formation, increase in the concentration of solutes and other undesired effects during the conversion of extracellular water into ice. This has generated the belief that oocyte storage cannot be achieved with the necessary efficiency and safety. However, many concerns raised by oocyte freezing are the result of unproven hypotheses or observations conducted under sometimes inappropriate conditions. For instance, spindle organization can undergo damage under certain freezing conditions but not with other protocols. The controversial suggestion that cryopreservation induces cortical granule discharge and zona pellucida hardening somehow questions the routine use of sperm microinjection. Damage to mouse oocytes caused by solute concentration is well documented but, in the human, there is no solid evidence that modifications of freezing mixtures, to prevent this problem, provide an actual advantage. The hope of developing oocyte cryopreservation as a major IVF option is becoming increasingly realistic, but major efforts are still required to clarify the authentic implications of oocyte cryopreservation at the cellular level and identify freezing conditions compatible with the preservation of viability and developmental ability.
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Affiliation(s)
- G Coticchio
- Tecnobios Procreazione, via Dante 15, 40125 Bologna, Italy.
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28
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De Santis L, Cino I, Rabellotti E, Papaleo E, Calzi F, Fusi FM, Brigante C, Ferrari A. Oocyte cryopreservation: clinical outcome of slow-cooling protocols differing in sucrose concentration. Reprod Biomed Online 2007; 14:57-63. [PMID: 17207332 DOI: 10.1016/s1472-6483(10)60764-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Oocyte cryopreservation represents an important option for management of female fertility, avoiding the ethical concerns associated with embryo storage. This retrospective study evaluated the clinical outcome of two alternative slow freezing protocols involving different sucrose concentrations. From January 2004 to March 2006, spare oocytes from selected couples undergoing IVF or intracytoplasmic sperm injection were frozen using a slow-cooling protocol and thawed at a later stage. Patients were divided into two groups: group A (n = 65), whose oocytes were frozen with propane-1,2-diol (PrOH) and 0.1 mol/l sucrose; and group B (n = 66) whose oocytes were frozen with 0.3 mol/l sucrose. A total of 543 oocytes were thawed in group A and 601 in group B, achieving a survival rate of 24.3 and 71.2% respectively. Whilst fertilization rate (53.5 and 80.4% respectively) was higher in group B, enhanced results for group A were achieved over all (implantation rate per transferred embryos 12.2 versus 5.7%; pregnancy rate per transfer 16.7 versus 9.5%). Normal births and ongoing pregnancies have occurred in both groups. Although in slow-cooling methods higher sucrose concentration in the freezing mixture allows higher post-thaw survival and fertilization rates, overall this did not coincide with an improved clinical outcome.
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Affiliation(s)
- L De Santis
- Vita-Salute University, IVF Unit, H S Raffaele, Via Olgettina 60, 20132 Milan, Italy.
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29
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Abstract
The Committee of Human Reproduction established by the Hungarian Ministry of Health is currently working on a proposition that has the intention to ban oocyte cryopreservation in Hungary temporarily. According to the notion of the committee, oocyte cryopreservation and the utilization of frozen oocytes entail enormous risks for future generations. They argue that the safety of the method is unproven. Consequently, their standpoint maintains that cryopreservation invariably remains a grave risk factor with regards to the genetic material of the oocyte by significantly increasing the risk to the offspring. Therefore,the Committee is requesting additional animal experiments to clarify the probability of permanent lesions to the spindle and alterations to the genetic material. According to their point of view, the suspension of the method is further justified since the efficiency of the procedure has yet not reached the level required for clinical adaptation. With the proposed forthcoming step,this commentary takes the opportunity to make critical comments and clarify necessary questions.
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Affiliation(s)
- Janos Konc
- Infertility and IVF Centre of Buda, Saint János Hospital, Budapest 1125, Hungary
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30
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Nottola SA, Macchiarelli G, Coticchio G, Bianchi S, Cecconi S, De Santis L, Scaravelli G, Flamigni C, Borini A. Ultrastructure of human mature oocytes after slow cooling cryopreservation using different sucrose concentrations†. Hum Reprod 2006; 22:1123-33. [PMID: 17158818 DOI: 10.1093/humrep/del463] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND We studied the ultrastructural characteristics of human mature oocytes frozen/thawed (F/T) using different concentrations of sucrose. Fresh human mature oocytes were used as controls. METHODS The oocytes (n = 48) were fixed in 1.5% glutaraldehyde at sampling (n = 16) or after freeze/thawing performed using a slow cooling method with propane-1,2-diol 1.5 mol/l and sucrose at either 0.1 mol/l (n = 16) or 0.3 mol/l (n = 16) in the freezing solution. The oocytes were then processed for electron microscopy observations. RESULTS Fresh and F/T oocytes belonging to both study groups were regularly rounded in sections, with a homogeneous cytoplasm and an intact zona pellucida (ZP). Organelles (mainly mitochondria-smooth endoplasmic reticulum aggregates and mitochondria-vesicle complexes) were abundant and uniformly dispersed in the ooplasm. The amount and density of cortical granules appeared to be abnormally reduced in some F/T samples, independently of the sucrose concentration in the freezing solution: this feature was frequently associated with an increased density of the inner ZP, possibly related to the occurrence of zona 'hardening'. Furthermore, slight to moderate microvacuolization was revealed in the ooplasm of some F/T oocytes, particularly in those treated with sucrose 0.3 mol/l. CONCLUSIONS Freeze/thawing procedures are associated with ultrastructural alterations in specific oocyte microdomains, presumably linked to the reduced developmental potential of mature cryopreserved oocytes. Further work is needed to determine whether or not a high concentration of sucrose plays a role, at least in part, in producing the above alterations.
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Affiliation(s)
- S A Nottola
- Department of Anatomy, University La Sapienza, Rome, Italy.
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31
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Boldt J, Tidswell N, Sayers A, Kilani R, Cline D. Human oocyte cryopreservation: 5-year experience with a sodium-depleted slow freezing method. Reprod Biomed Online 2006; 13:96-100. [PMID: 16820118 DOI: 10.1016/s1472-6483(10)62021-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
A slow freezing/rapid thawing method for the cryopreservation of human oocytes has been employed using a sodium-depleted culture media. In 53 frozen egg-embryo transfer (FEET) cycles, a 60.4% survival rate post-thaw was obtained and a 62.0% fertilization rate following intracytoplasmic sperm injection. Overall pregnancy rates were 26.4% per thaw attempt, 30.4% per patient, and 32.6% per embryo transfer. Pregnancy rates using sodium-depleted phosphate-buffered saline (PBS) as the base medium were 20.0% per thaw, 21.7% per patient, and 26.3% per transfer. With sodium-depleted modified human tubal fluid (mHTF) as the base for the cryopreservation medium, rates were 32.1% per thaw attempt, 39.1% per patient, 37.5% per transfer. The overall implantation rates were 4.2% per thawed oocyte and 13.6% per embryo, (PBS: 3.0% per egg, 10.6% per embryo; mHTF:5.3% per oocyte; 15.9% per embryo). These data indicate that the use of a sodium-depleted media with slow freezing and rapid thawing can yield acceptable pregnancy rates after FEET.
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Affiliation(s)
- Jeffrey Boldt
- Assisted Fertility Services, Community Health Network, Indianapolis, IN, USA.
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32
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Li G, Thirumala S, Leibo SP, Devireddy RV. Subzero water transport characteristics and optimal rates of freezing rhesus monkey (Macaca mulatta) ovarian tissue. Mol Reprod Dev 2006; 73:1600-11. [PMID: 16902954 DOI: 10.1002/mrd.20541] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The purpose of the present study was to examine the effect of two different suprazero (room temperature +25 degrees C to +4 degrees C) cooling conditions on the measured water transport response of primate (Macaca mulatta) ovarian tissue in the presence and absence of cryoprotective agents (CPAs). Freshly collected Macaca mulatta (rhesus monkey) ovarian tissue sections were cooled at either 0.5 degrees C/min or 40 degrees C/min from 25 to 4 degrees C. A shape independent differential scanning calorimeter (DSC) technique was then used to measure the volumetric shrinkage during freezing of ovarian tissue sections at a freezing rate of 5 degrees C/min in the presence and absence of three different CPAs (0.85 M glycerol, 0.85 M dimethylsulfoxide, and 0.85 M ethylene glycol). Thus, water transport during freezing of primate ovarian tissue was obtained at eight different conditions (i.e., at four different freezing media with two different suprazero cooling conditions). The water transport response of ovarian tissue cooled rapidly from 25 to 4 degrees C was significantly different (P < 0.01) than that of slow cooled tissue, in the freezing media without CPAs and with dimethylsulfoxide. However, the differences in the measured water transport response due to the imposed suprazero cooling conditions were reduced with the addition of glycerol and ethylene glycol (statistically different with P < 0.05). By fitting a model of water transport to the experimentally obtained volumetric shrinkage data the best-fit membrane permeability parameters (L(pg) and E(Lp)) were determined. The best-fit parameters of water transport in primate ovarian tissue sections ranged from: L(pg) = 0.7 to 0.15 microm/min-atm and E(Lp) = 22.1 to 32.1 kcal/mol (the goodness of fit parameter, R(2) > 0.96). These parameters suggest that the "optimal rates of cryopreservation" for ovarian tissue are significantly dependent upon suprazero cooling conditions and the choice of CPA.
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Affiliation(s)
- G Li
- Bioengineering Laboratory, Department of Mechanical Engineering, Louisiana State University, Baton Rouge, 70803, USA
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33
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Bibliography. Current world literature. Fertility. Curr Opin Obstet Gynecol 2006; 18:344-53. [PMID: 16735837 DOI: 10.1097/01.gco.0000193023.28556.e2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
PURPOSE OF REVIEW This article reviews human oocyte cryopreservation, one of the most stimulating challenges of assisted reproduction technology. Since the first steps in assisted reproduction technology, researchers have pursued this goal, to greatly improve the management of infertility treatments. This present review depicts the present state of research and clinical applications of this methodology. RECENT FINDINGS Recent literature focuses on the possible mechanisms of oocyte damage caused by temperature and cryoprotectant injury and forecasts possible technological solutions. Several papers illustrate encouraging results in the increasing clinical application of this procedure. SUMMARY Findings give support to several indications of human female gamete cryostorage. Oocyte cryopreservation might replace embryo freezing. Egg freezing offers an alternative to women at risk of losing their reproductive function, caused by antineoplastic treatments, endometriosis, ovarian surgery or genetic premature ovarian failure. In addition, oocyte storage may contribute to an increase in in-vitro fertilization flexibility. Despite the early disappointing results, recent technical modifications have improved the clinical efficiency greatly, with the birth of several healthy children.
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Affiliation(s)
- Eleonora Porcu
- Infertility and IVF Center, Reproductive Medicine Unit, Department Of Obstetrics and Gynecology, University of Bologna, Bologna, Italy.
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Coticchio G, De Santis L, Rossi G, Borini A, Albertini D, Scaravelli G, Alecci C, Bianchi V, Nottola S, Cecconi S. Sucrose concentration influences the rate of human oocytes with normal spindle and chromosome configurations after slow-cooling cryopreservation. Hum Reprod 2006; 21:1771-6. [PMID: 16549422 DOI: 10.1093/humrep/del073] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Recently described slow-cooling cryopreservation protocols involving elevated sucrose concentration have improved survival frequencies of human oocytes, potentially overcoming a major hurdle that has limited the adoption of oocyte storage. Because implantation rates of embryos from frozen oocytes remain generally low, it is still debated whether, irrespective of survival rates, this form of cryopreservation leads inevitably to the disruption or complete loss of the metaphase II (MII) spindle. METHODS Human oocytes with an extruded polar body I (PBI) were cryopreserved using a slow-cooling method including 1.5 mol/l propane-1,2-diol (PrOH) and alternative sucrose concentrations (either 0.1 or 0.3 mol/l) in the freezing solution. Fresh control and frozen-thawed survived oocytes were analysed by confocal microscopy to evaluate MII spindle and chromosome organizations. RESULTS Of the 104 oocytes included in the unfrozen group, 76 (73.1%) displayed normal bipolar spindles with equatorially aligned chromosomes. Spindle and chromatin organizations were significantly affected (50.8%) after cryopreservation involving lower sucrose concentration (61 oocytes), whereas these parameters were unchanged (69.7%) using the 0.3 mol/l sucrose protocol (152 oocytes). CONCLUSIONS Partial disruption of the MII spindle and associated chromosomes accompanies inadequate cryopreservation during slow cooling. However, protocols adopting higher sucrose concentration in the freezing solution promote the retention of an intact chromosome segregation apparatus comparable in incidence to freshly collected oocytes.
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Devireddy RV, Li G, Leibo SP. Suprazero cooling conditions significantly influence subzero permeability parameters of mammalian ovarian tissue. Mol Reprod Dev 2006; 73:330-41. [PMID: 16362972 DOI: 10.1002/mrd.20418] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
To model the cryobiological responses of cells and tissues, permeability characteristics are often measured at suprazero temperatures and the measured values are used to predict the responses at subzero temperatures. The purpose of the present study was to determine whether the rate of cooling from +25 to +4 degrees C influenced the measured water transport response of ovarian tissue at subzero temperatures in the presence or absence of cryoprotective agents (CPAs). Sections of freshly collected equine ovarian tissue were first cooled either at 40 degrees C/min or at 0.5 degrees C/min from 25 to 4 degrees C, and then cooled to subzero temperatures. A shape-independent differential scanning calorimeter (DSC) technique was used to measure the volumetric shrinkage during freezing of equine ovarian tissue sections. After ice was induced to form in the extracellular fluid within the specimen, the sample was frozen from the phase change temperature to -50 degrees C at 5 degrees C/min. Replicate samples were frozen in isotonic medium alone or in medium containing 0.85 M glycerol or 0.85 M dimethylsulfoxide. The water transport response of ovarian tissue samples cooled at 40 degrees C/min from 25 to 4 degrees C was significantly different (confidence level >95%) from that of tissue samples cooled at 0.5 degrees C/min, whether in the presence or absence of CPAs. We fitted a model of water transport to the experimentally-derived volumetric shrinkage data and determined the best-fit membrane permeability parameters (L(pg) and E(Lp)) of equine ovarian tissue during freezing. Subzero water transport parameters of ovarian tissue samples cooled at 0.5 degrees C/min from 25 to 4 degrees C ranged from: L(pg) = 0.06 to 0.73 microm/min.atm and E(Lp) = 6.1 to 20.5 kcal/mol. The corresponding parameters of samples cooled at 40 degrees C/min from 25 to 4 degrees C ranged from: L(pg) = 0.04 to 0.61 microm/min.atm and E(Lp) = 8.2 to 54.2 kcal/mol. Calculations made of the theoretical response of tissue at subzero temperatures suggest that the optimal cooling rates to cryopreserve ovarian tissue are significantly dependent upon suprazero cooling conditions.
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Affiliation(s)
- R V Devireddy
- Bioengineering Laboratory, Department of Mechanical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
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37
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Koutlaki N, Schoepper B, Maroulis G, Diedrich K, Al-Hasani S. Human oocyte cryopreservation: past, present and future. Reprod Biomed Online 2006; 13:427-36. [PMID: 16984778 DOI: 10.1016/s1472-6483(10)61449-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Despite inferior results in the past compared with embryo freezing, oocyte cryopreservation has made great strides in recent years. In fact, it has become a necessity in assisted reproduction technology, providing alternatives to legal, moral and religious problems originating from embryo freezing. Recent advances in freezing technology, modifications of conventional protocols used and continuing optimization of vitrification have efficiently improved the method. A historical description of the method's progression over time, and a comparison of principles, procedures and results as reported in the literature are presented in this review.
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Affiliation(s)
- N Koutlaki
- Department of Obstetrics and Gynecology, University of Schleswig-Holstein, Luebeck, Germany
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38
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Borini A, Sciajno R, Bianchi V, Sereni E, Flamigni C, Coticchio G. Clinical outcome of oocyte cryopreservation after slow cooling with a protocol utilizing a high sucrose concentration. Hum Reprod 2005; 21:512-7. [PMID: 16239316 DOI: 10.1093/humrep/dei346] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Recently, interest in oocyte cryopreservation has steadily increased. Newly developed protocols have dramatically improved survival rates, removing perhaps the major hurdle that has prevented this approach from becoming a fully established form of treatment. However, the clinical efficiency of these protocols has not been exhaustively explored and therefore remains controversial. METHODS Morphologically normal oocytes displaying the first polar body were frozen-thawed with a slow cooling protocol that utilized 1.5 mol/l propane-1,2-diol (PrOH) and 0.3 mol/l sucrose. RESULTS A total of 927 oocytes from 146 patients were frozen-thawed, achieving a 74.1% survival rate. Over 76% of microinjected oocytes displayed two pronuclei 16 h post-insemination, while the proportion of embryos at 44-46 h post-insemination was 90.2%. At this time point, the majority (68.3%) of embryos were at the two-cell stage, showing in most cases (78.7%) minimal or moderate fragmentation. Eighteen clinical pregnancies, three of which were twin, were observed, giving rise to rates of 12.3 and 9.7%, calculated per patient and per embryo transfer, respectively. The implantation rate was 5.2%. To date, four children have been born and three pregnancies resulted in spontaneous abortions, while the remaining pregnancies are ongoing. CONCLUSIONS Our data indicate that although the combination of slow cooling and high sucrose concentration ensures high rates of oocyte survival, it is not sufficient to guarantee a high standard of clinical efficiency.
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Affiliation(s)
- A Borini
- Tecnobios Procreazione, Via Dante 15 University of Bologna, 40125 Bologna, Italy
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Abstract
Reports of clinical pregnancies from cryopreserved human oocytes have been steadily increasing in recent years. However, success in terms of births per thawed oocyte remains poor. A wide variety of freezing techniques has been used lately, but modifications to protocols are made on an empirical basis. Methods of cryopreservation are often poorly described or protocols are not strictly adhered to, resulting in variability of outcome. The first stage of a freezing protocol is exposure to cryoprotectant. If performed inappropriately, such exposure can result in damage due to chemical toxicity and/or osmotic stress. Measurement of cell volume change during exposure to cryoprotectants demonstrates the extent of osmotic stress experienced by that cell. Such measurements have been performed during perfusion of murine and human oocytes with cryoprotectant concentrations commonly used for cryopreservation of these cells. It has been demonstrated that changes in the cryoprotectant type, concentration and temperature of exposure can dramatically affect the extent of cell volume change. Even small changes in duration of exposure to cryoprotectant prior to cooling can result in drastic changes in cellular hydration. Such factors will potentially influence the ability of the cell to survive the stresses experienced during the subsequent stages of the cryopreservation protocol.
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Affiliation(s)
- S J Paynter
- Department of Obstetrics and Gynaecology, Wales College of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
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Coticchio G, Bonu MA, Bianchi V, Flamigni C, Borini A. Criteria to assess human oocyte quality after cryopreservation. Reprod Biomed Online 2005; 11:421-7. [PMID: 16274599 DOI: 10.1016/s1472-6483(10)61133-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Oocyte cryopreservation certainly represents one of the most attractive developments in the field of assisted reproduction, with the aim of preserving female fertility and circumventing the ethical and legal drawbacks associated with embryo freezing. Despite the achievement of the first pregnancy from frozen oocytes dating back as early as 1987, since then fewer than 150 pregnancies have been reported. Over a long period of time, application of oocyte storage on a large scale has been prevented by various factors, namely poor post-thaw survival. Fertilization rates remained low even after the introduction of intracytoplasmic sperm injection. Modifications of slow-freezing protocols, mainly based on the increase of the concentration of sucrose used as non-penetrating cryoprotectant (CPA) and the replacement of sodium with choline, appear to have decisively improved survival rates to over 80%. Investigations at the cellular level on thawed oocytes are largely lacking. Fertilization rates have also benefited from protocol modifications, reaching values indistinguishable from those normally obtained with fresh material. Vitrification protocols have also been tested, giving rise to improvements whose reproducibility is still uncertain. Data on the dynamics of fertilization and preimplantation development of embryos derived from frozen oocytes are extremely scarce. At the moment, clinical efficiency of oocyte cryopreservation cannot be precisely assessed because of the lack of controlled studies, although it appears to be considerably lower than that achieved with embryo freezing. In summary, encouraging advances have been made in the field of oocyte cryopreservation, but presently no protocol can ensure standards of success and safety comparable to those guaranteed by embryo storage.
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Affiliation(s)
- G Coticchio
- Tecnobios Procreazione, Via Dante 15, 40125 Bologna, Italy.
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