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Boylan CF, Sambo KM, Neal-Perry G, Brayboy LM. Ex ovo omnia-why don't we know more about egg quality via imaging? Biol Reprod 2024; 110:1201-1212. [PMID: 38767842 PMCID: PMC11180616 DOI: 10.1093/biolre/ioae080] [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: 01/16/2024] [Revised: 05/14/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024] Open
Abstract
Determining egg quality is the foremost challenge in assisted reproductive technology (ART). Although extensive advances have been made in multiple areas of ART over the last 40 years, oocyte quality assessment tools have not much evolved beyond standard morphological observation. The oocyte not only delivers half of the nuclear genetic material and all of the mitochondrial DNA to an embryo but also provides complete developmental support during embryonic growth. Oocyte mitochondrial numbers far exceed those of any somatic cell, yet little work has been done to evaluate the mitochondrial bioenergetics of an oocyte. Current standard oocyte assessment in in vitro fertilization (IVF) centers include the observation of oocytes and their surrounding cell complex (cumulus cells) via stereomicroscope or inverted microscope, which is largely primitive. Additional oocyte assessments include polar body grading and polarized light meiotic spindle imaging. However, the evidence regarding the aforementioned methods of oocyte quality assessment and IVF outcomes is contradictory and non-reproducible. High-resolution microscopy techniques have also been implemented in animal and human models with promising outcomes. The current era of oocyte imaging continues to evolve with discoveries in artificial intelligence models of oocyte morphology selection albeit at a slow rate. In this review, the past, current, and future oocyte imaging techniques will be examined with the goal of drawing attention to the gap which limits our ability to assess oocytes in real time. The implications of improved oocyte imaging techniques on patients undergoing IVF will be discussed as well as the need to develop point of care oocyte assessment testing in IVF labs.
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Affiliation(s)
- Caitlin F Boylan
- University of North Carolina, Chapel Hill, NC, USA
- Eastern Virginia Medical School, Norfolk, VA, USA
| | - Keshia M Sambo
- Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | | | - Lynae M Brayboy
- Department of Neuropediatrics Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Klinik für Pädiatrie m. S. Neurologie, Charité Campus Virchow Klinikum, Berlin, Germany
- Department of Reproductive Biology, Bedford Research Foundation, Bedford, MA, USA
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2
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Yazdani A, Halvaei I, Boniface C, Esfandiari N. Effect of cytoplasmic fragmentation on embryo development, quality, and pregnancy outcome: a systematic review of the literature. Reprod Biol Endocrinol 2024; 22:55. [PMID: 38745305 PMCID: PMC11092204 DOI: 10.1186/s12958-024-01217-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 04/01/2024] [Indexed: 05/16/2024] Open
Abstract
The role of cytoplasmic fragmentation in human embryo development and reproductive potential is widely recognized, albeit without standard definition nor agreed upon implication. While fragmentation is best understood to be a natural process across species, the origin of fragmentation remains incompletely understood and likely multifactorial. Several factors including embryo culture condition, gamete quality, aneuploidy, and abnormal cytokinesis seem to have important role in the etiology of cytoplasmic fragmentation. Fragmentation reduces the volume of cytoplasm and depletes embryo of essential organelles and regulatory proteins, compromising the developmental potential of the embryo. While it has been shown that degree of fragmentation and embryo implantation potential are inversely proportional, the degree, pattern, and distribution of fragmentation as it relates to pregnancy outcome is debated in the literature. This review highlights some of the challenges in analysis of fragmentation, while revealing trends in our evolving knowledge of how fragmentation may relate to functional development of the human embryos, implantation, and pregnancy outcome.
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Affiliation(s)
- Ariella Yazdani
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont Medical Center, The Robert Larner College of Medicine at the University of Vermont, Burlington, VT, 05405, USA
- Present address: Obstetrics and Gynecology Institute, Cleveland Clinic Foundation, Cleveland, OH, 44195, USA
| | - Iman Halvaei
- Department of Anatomical Sciences, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Catherine Boniface
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont Medical Center, The Robert Larner College of Medicine at the University of Vermont, Burlington, VT, 05405, USA
| | - Navid Esfandiari
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont Medical Center, The Robert Larner College of Medicine at the University of Vermont, Burlington, VT, 05405, USA.
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology and Reproductive Sciences, University of Vermont, 111 Colchester Avenue, Burlington, Vermont, 05401, USA.
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Sciorio R, Cariati F, Fleming S, Alviggi C. Exploring the Impact of Controlled Ovarian Stimulation and Non-Invasive Oocyte Assessment in ART Treatments. Life (Basel) 2023; 13:1989. [PMID: 37895371 PMCID: PMC10608727 DOI: 10.3390/life13101989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/14/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023] Open
Abstract
Invasive and noninvasive features are normally applied to select developmentally competent oocytes and embryos that can increase the take-home baby rates in assisted reproductive technology. The noninvasive approach mainly applied to determine oocyte and embryo competence has been, since the early days of IVF, the morphological evaluation of the mature cumulus-oocyte complex at the time of pickup, first polar body, zona pellucida thickness, perivitelline space and cytoplasm appearance. Morphological evaluation of oocyte quality is one of the options used to predict successful fertilization, early embryo development, uterine implantation and the capacity of an embryo to generate a healthy pregnancy to term. Thus, this paper aims to provide an analytical revision of the current literature relating to the correlation between ovarian stimulation procedures and oocyte/embryo quality. In detail, several aspects of oocyte quality such as morphological features, oocyte competence and its surrounding environment will be discussed. In addition, the main noninvasive features as well as novel approaches to biomechanical parameters of oocytes that might be correlated with the competence of embryos to produce a healthy pregnancy and live birth will be illustrated.
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Affiliation(s)
- Romualdo Sciorio
- Fertility Medicine and Gynaecological Endocrinology Unit, Department Woman-Mother-Child, Lausanne University Hospital, CHUV, 1011 Lausanne, Switzerland
| | - Federica Cariati
- Department of Public Health, University of Naples Federico II, Via Pansini 5, 80131 Napoli, Italy;
| | - Steven Fleming
- Discipline of Anatomy & Histology, School of Medical Sciences, University of Sydney, Sydney, NSW 2006, Australia;
| | - Carlo Alviggi
- Fertility Unit, Maternal-Child Department, AOU Policlinico Federico II, 80131 Naples, Italy;
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, University of Naples Federico II, 80131 Naples, Italy
- Endocrinology and Experimental Oncology Institute (IEOS), National Research Council, 80131 Naples, Italy
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Assisted Reproductive Technology without Embryo Discarding or Freezing in Women ≥40 Years: A 5-Year Retrospective Study at a Single Center in Italy. J Clin Med 2023; 12:jcm12020504. [PMID: 36675433 PMCID: PMC9862537 DOI: 10.3390/jcm12020504] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
The protocols commonly used in assisted reproductive technology (ART) consist of long-term embryo culture up to the blastocyst stage after the insemination of all mature oocytes, the freezing of all the embryos produced, and their subsequent transfer one by one. These practices, along with preimplantation genetic testing, although developed to improve the live birth rate (LBR) and reduce the risk of multiple pregnancies, are drawing attention to the possible increase in obstetric and perinatal risks, and adverse epigenetic consequences in offspring. Furthermore, ethical-legal concerns are growing regarding the increase in cryopreservation and storage of frozen embryos. In an attempt to reduce the risk associated with prolonged embryo culture and avoid embryo storage, we have chosen to inseminate a limited number of oocytes not exceeding the number of embryos to be transferred, after two days or less of culture. We retrospectively analyzed 245 ICSI cycles performed in 184 infertile couples with a female partner aged ≥40 from January 2016 to July 2021. The results showed a fertilization rate of 95.7%, a miscarriage rate of 48.9%, and a LBR of 10% with twin pregnancies of 16.7%. The cumulative LBR in our group of couples was 13%. No embryos were frozen. In conclusion, these results suggest that oocyte selection and embryo transfer at the cleaving stage constitute a practice that has a LBR comparable to that of the more commonly used protocols in older women who have reduced ovarian reserve.
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Sciorio R, Miranian D, Smith GD. Non-invasive oocyte quality assessment. Biol Reprod 2022; 106:274-290. [PMID: 35136962 DOI: 10.1093/biolre/ioac009] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 01/04/2022] [Accepted: 01/11/2022] [Indexed: 12/27/2022] Open
Abstract
Oocyte quality is perhaps the most important limiting factor in female fertility; however, the current methods of determining oocyte competence are only marginally capable of predicting a successful pregnancy. We aim to review the predictive value of non-invasive techniques for the assessment of human oocytes and their related cells and biofluids that pertain to their developmental competence. Investigation of the proteome, transcriptome, and hormonal makeup of follicular fluid, as well as cumulus-oocyte complexes are currently underway; however, prospective randomized non-selection-controlled trials of the future are needed before determining their prognostic value. The biological significance of polar body morphology and genetics are still unknown and the subject of debate. The predictive utility of zygotic viscoelasticity for embryo development has been demonstrated, but similar studies performed on oocytes have yet to be conducted. Metabolic profiling of culture media using human oocytes are also limited and may require integration of automated, high-throughput targeted metabolomic assessments in real time with microfluidic platforms. Light exposure to oocytes can be detrimental to subsequent development and utilization of time-lapse imaging and morphometrics of oocytes is wanting. Polarized light, Raman microspectroscopy, and coherent anti-Stokes Raman scattering are a few novel imaging tools that may play a more important role in future oocyte assessment. Ultimately, the integration of chemistry, genomics, microfluidics, microscopy, physics, and other biomedical engineering technologies into the basic studies of oocyte biology, and in testing and perfecting practical solutions of oocyte evaluation, are the future for non-invasive assessment of oocytes.
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Affiliation(s)
- Romualdo Sciorio
- Edinburgh Assisted Conception Programme, EFREC, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - Daniel Miranian
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA
| | - Gary D Smith
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA.,Department of Physiology, Urology, and Reproductive Sciences Program, University of Michigan, Ann Arbor, MI, USA
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Human Oocyte Morphology and Outcomes of Infertility Treatment: a Systematic Review. Reprod Sci 2021; 29:2768-2785. [PMID: 34816375 DOI: 10.1007/s43032-021-00723-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/22/2021] [Indexed: 10/19/2022]
Abstract
Oocyte morphology assessment is easy to implement in any laboratory with possible quality grading prior to fertilization. At present, comprehensive oocyte morphology scoring is not performed as a routine procedure. However, it may augment chances for successful treatment outcomes if a correlation with certain dysmorphisms can be proven. In order to determine a correlation between oocyte morphology and treatment outcome, we performed a systematic search in PubMed and Cochrane Controlled Trials Register following PRISMA guidelines. A total of 52 articles out of 6,755 search results met the inclusion criteria. Dark colour of the cytoplasm (observed with an incidence rate of 7%), homogeneous granularity of the cytoplasm (19%) and ovoid shape of oocytes (7%) appeared to have no influence on treatment outcome. Abnormalities such as refractile bodies (10%), fragmented first polar body (37%), dark zona pellucida (9%), enlarged perivitelline space (18%) and debris in it (21%) are likely to affect the treatment outcome to some extent. Finally, cytoplasmic vacuoles (4%), centrally located cytoplasmic granularity (12%) and clusters of smooth endoplasmic reticulum (4%) negatively impact infertility treatment outcomes. Nonetheless, morphological assessment is informative rather than predictive. Adding oocyte morphology to the artificial intelligence (AI)-driven selection process may improve the precision of the algorithms. Oocyte morphology assessment can be especially useful in oocyte donation cycles, during oocyte freezing for fertility preservation and finally, objective oocyte scoring can be important in cases of very poor treatment outcome as a tool for explanation of results to the patient.
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Oocyte Selection for In Vitro Embryo Production in Bovine Species: Noninvasive Approaches for New Challenges of Oocyte Competence. Animals (Basel) 2020; 10:ani10122196. [PMID: 33255250 PMCID: PMC7760727 DOI: 10.3390/ani10122196] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022] Open
Abstract
Simple Summary The efficiency of producing embryos using in vitro technologies in cattle species remains lower when compared to mice, indicating that the proportion of female gametes that fail to develop after in vitro manipulation is considerably large. Considering that the intrinsic quality of the oocyte is one of the main factors affecting embryo production, the precise identification of noninvasive markers that predict oocyte competence is of major interest. The aim of this review was to explore the current literature on different noninvasive markers associated with oocyte quality in the bovine model. Apart from some controversial findings, the presence of cycle-related structures in ovaries, a follicle size between 6 and 10 mm, a large slightly expanded investment without dark areas, large oocyte diameter (>120 microns), dark cytoplasm, and the presence of a round and smooth first polar body have been associated with better embryonic development. In addition, the combination of oocyte and zygote selection, spindle imaging, and the anti-Stokes Raman scattering microscopy together with studies decoding molecular cues in oocyte maturation have the potential to further optimize the identification of oocytes with better developmental competence for in vitro technologies in livestock species. Abstract The efficiency of producing embryos using in vitro technologies in livestock species rarely exceeds the 30–40% threshold, indicating that the proportion of oocytes that fail to develop after in vitro fertilization and culture is considerably large. Considering that the intrinsic quality of the oocyte is one of the main factors affecting blastocyst yield, the precise identification of noninvasive cellular or molecular markers that predict oocyte competence is of major interest to research and practical applications. The aim of this review was to explore the current literature on different noninvasive markers associated with oocyte quality in the bovine model. Apart from some controversial findings, the presence of cycle-related structures in ovaries, a follicle size between 6 and 10 mm, large number of surrounding cumulus cells, slightly expanded investment without dark areas, large oocyte diameter (>120 microns), dark cytoplasm, and the presence of a round and smooth first polar body have been associated with better competence. In addition, the combination of oocyte and zygote selection via brilliant cresyl blue (BCB) test, spindle imaging, and the anti-Stokes Raman scattering microscopy together with studies decoding molecular cues in oocyte maturation have the potential to further optimize the identification of oocytes with better developmental competence for in-vitro-derived technologies in livestock species.
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Ozturk S. Selection of competent oocytes by morphological criteria for assisted reproductive technologies. Mol Reprod Dev 2020; 87:1021-1036. [PMID: 32902927 DOI: 10.1002/mrd.23420] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 07/17/2020] [Accepted: 08/22/2020] [Indexed: 02/06/2023]
Abstract
Invasive and noninvasive methods are commonly used to select developmentally competent oocytes that can improve the take-home baby rates in assisted reproductive technology (ART) centers. One of the noninvasive methods conventionally utilized to determine competent oocytes is the morphological analysis of cumulus complex, first polar body, zona pellucida, perivitelline space, meiotic spindle, and ooplasm. Successful fertilization, early embryo development, uterine implantation, and healthy pregnancy depend on the quality of oocytes, and morphological evaluation is one of the options used to predict quality levels. In this review, the morphological criteria being utilized in certain ART centers are comprehensively evaluated with special references to their predictive values and potential contributions to selecting high-quality oocytes.
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Affiliation(s)
- Saffet Ozturk
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya, Turkey
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Hoshino Y. Updating the markers for oocyte quality evaluation: intracellular temperature as a new index. Reprod Med Biol 2018; 17:434-441. [PMID: 30377396 PMCID: PMC6194278 DOI: 10.1002/rmb2.12245] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/07/2018] [Accepted: 08/09/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The developmental competence of an embryo is principally dictated by the oocyte. Usually, oocyte selection is based on morphological properties; however, all morphological criteria that are currently used for the grading and screening of oocytes are not able to eliminate the subjectivity. Despite recent studies of the molecular factors related to oocyte quality, it is technically difficult to develop an index based on these factors, and new indices that reflect intracellular conditions are necessary. METHODS Morphological and molecular factors influencing developmental competence were comprehensively reviewed, and intracellular temperature was evaluated as a new marker of oocyte quality. MAIN FINDINGS The intracellular temperature of mature oocytes was high in fresh oocytes and decreased with time after polar body release. Under the same conditions, the intracellular temperature and its distribution differed among oocytes, suggesting that temperature represents the state of each oocyte. CONCLUSION Intracellular temperature is advantageous as an objective and quantitative indicator of oocyte quality. Further studies should evaluate the link between temperature and cellular phenomena to establish its use as an indicator of quality.
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Affiliation(s)
- Yumi Hoshino
- Graduate School of Biosphere ScienceHiroshima UniversityHiroshimaJapan
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Dal Canto M, Guglielmo MC, Mignini Renzini M, Fadini R, Moutier C, Merola M, De Ponti E, Coticchio G. Dysmorphic patterns are associated with cytoskeletal alterations in human oocytes. Hum Reprod 2017; 32:750-757. [PMID: 28333241 DOI: 10.1093/humrep/dex041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/14/2017] [Indexed: 01/09/2023] Open
Abstract
Study question Are specific morphological anomalies in human mature oocytes, as revealed by transmitted light microscopy, associated with intrinsic damage to the meiotic spindle and actin cytoskeleton? Summary answer Aggregates of smooth endoplasmic reticulum (SER) and domains of centrally localized granular cytoplasm (GC) reflect intrinsic damage to the oocyte cytoskeleton, namely alterations in spindle size, chromosome misalignment and cortical actin disorganization. What is known already In preparation for ICSI, oocytes are often selected for use in treatment by morphological criteria, but the rationale and implications of this practice are controversial. Very little information is available on the relationship between oocyte morphology and intrinsic cellular characteristics, such as the actin cytoskeleton, meiotic spindle and chromosome alignment. Study design, size, duration A total of 170 metaphase II (MII) oocytes were donated by consenting IVF patients and analysed; 62 were classified as morphologically normal (control), 54 had SER clusters and 54 had centrally localized GC. Participants/materials, setting, methods Supernumerary oocytes were fixed within 3 h from recovery and stained for tubulin, chromatin and actin. Spindles were analysed for 1D and 2D characteristics by high-performance confocal microscopy. Chromosomes were classified as scattered or aligned and the conformation and intensity of cortical actin was evaluated. Main results and the role of chance In comparison with control oocytes, both SER and GC oocytes showed greater spindle length (P = 0.033 and 0.003, respectively) and GC oocytes also showed greater spindle width (P= 0.049) and area (P= 0.036). Control and SER oocytes had statistically comparable rates of chromosome displacement from the metaphase plate, unlike GC oocytes where chromosome displacement occurred at higher rate (P = 0.013). In situations where a complete Z-stack was reconstructed from a polar angle, chromosome disposition was classified as being normal when two sets of concentric arrays were visible. Based on these parameters, the proportions of oocytes with normal chromosomal arrangement or partial/total disarrangement was not statistically different between control and SER oocytes. Conversely, in GC oocytes, chromosome disarrangement was higher (P = 0.002). All control oocytes displayed a continuous meshwork of suboolemmal actin, which appeared as an uninterrupted ring in thin optical sections. In contrast, in SER and GC groups, integrity of suboolemmal actin was observed in only 66.7 and 42.9% of oocytes, respectively (P = 0.0001). Large scale data N/A. Limitations reason for caution Only two of several known oocyte dysmorphisms were investigated, while oocyte quality was assessed only by cytoskeletal criteria. Wider implications of the findings This study represents a significant step toward a more objective assessment of oocyte morphology, offering information that can assist embryologists to make a more aware and rationally founded decision on whether, and with what possible implications, oocytes with certain dysmorphic characters should be used for treatment or discarded. More generally, it also demonstrates that morphometric parameters of the cytoskeleton and chromosome organization can be used as biomarkers of oocyte quality. Study funding and competing interest(s) This study was funded by Biogenesi Reproductive Medicine Centre (Monza, Italy). All authors declare no conflict of interests.
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Affiliation(s)
| | | | - Mario Mignini Renzini
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi, Monza,Italy
| | - Rubens Fadini
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi, Monza,Italy
| | - Clarissa Moutier
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi, Monza,Italy
| | - Maria Merola
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi, Monza,Italy
| | - Elena De Ponti
- Department of Medical Physics, ASST Monza, Via Pergolesi, Monza, Italy
| | - Giovanni Coticchio
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi, Monza,Italy
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Xiong S, Han W, Liu W, Wu L, Liu JX, Gao Y, Huang G. Developmental potential of embryos from cycles containing oocytes with severe ovoid zona pellucida. HUM FERTIL 2017; 21:204-211. [PMID: 28545306 DOI: 10.1080/14647273.2017.1324181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The purpose of this study was to determine the incidence of oocytes with severe ovoid zona pellucida (ZP), investigate the development potential of their sibling oocytes and the clinical outcomes from affected cycles. The data were collected from our medical records. Cycles having at least one oocyte with severe ovoid ZP were defined as the 'severe ovoid group', cycles having at least one oocyte with mild ovoid ZP were defined as the 'mild ovoid group', whereas cycles without oocytes with ovoid ZPs were defined as the 'control group' (n = 150 for each group). The results showed that sibling embryos in the 'severe ovoid group' were characterized by delayed development and lower available embryo rate. The implantation, clinical pregnancy and live birth rates in this group were also significantly lower than that in the other two groups. There were five cycles in which only one embryo with severe ovoid ZP was transferred and two healthy babies were born. The mild ovoid group showed comparable embryo development and clinical outcomes compared with the control group. This study suggests that cycles containing oocytes with severe ovoid ZPs had delayed embryo development, lower available embryo rate, compromised implantation, clinical pregnancy and live birth rates.
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Affiliation(s)
- Shun Xiong
- a Chongqing Reproductive and Genetics Institute , Chongqing , China
| | - Wei Han
- b Chongqing Obstetrics and Gynecology Hospital , Chongqing , China
| | - Weiwei Liu
- a Chongqing Reproductive and Genetics Institute , Chongqing , China
| | - Lihong Wu
- a Chongqing Reproductive and Genetics Institute , Chongqing , China
| | - Jun Xia Liu
- a Chongqing Reproductive and Genetics Institute , Chongqing , China
| | - Yang Gao
- a Chongqing Reproductive and Genetics Institute , Chongqing , China
| | - Guoning Huang
- a Chongqing Reproductive and Genetics Institute , Chongqing , China
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Abstract
The aim of this study was to explore whether the morphology of polar bodies (PBs) estimated at 16-18 h after insemination can be used as an additional marker for predicting human embryo quality or pregnancy outcome. The data from 355 patients who received standard in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment after controlled ovarian hyperstimulation were recruited. Normal fertilized 3048 zygotes from 382 cycles were divided into two groups, PBs intact or fragmented, according to the morphology of PBs assessed at 16-18 h after insemination. Embryo quality and pregnancy outcome were compared between the two groups. It was shown that the day 3 (D3) good embryo rate, good quality blastocyst rate and available embryo rate of the PBs intact group were all significantly higher than that of the corresponding fragmented groups. However, no significant differences in pregnancy rate (PR) or implantation rate (IR) were observed between the intact and fragmented groups. Although PBs morphology estimated at 16-18 h after insemination had little effect on PR or IR in fresh embryo transfer cycles, a better embryo quality can be achieved in the PB-intact group, which is valuable for embryo selection.
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13
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Coticchio G, Dal Canto M, Mignini Renzini M, Guglielmo MC, Brambillasca F, Turchi D, Novara PV, Fadini R. Oocyte maturation: gamete-somatic cells interactions, meiotic resumption, cytoskeletal dynamics and cytoplasmic reorganization. Hum Reprod Update 2015; 21:427-54. [PMID: 25744083 DOI: 10.1093/humupd/dmv011] [Citation(s) in RCA: 322] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 02/11/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND In a growth phase occurring during most of folliculogenesis, the oocyte produces and accumulates molecules and organelles that are fundamental for the development of the preimplantation embryo. At ovulation, growth is followed by a phase of maturation that, although confined within a short temporal window, encompasses modifications of the oocyte chromosome complement and rearrangements of cytoplasmic components that are crucial for the achievement of developmental competence. Cumulus cells (CCs) are central to the process of maturation, providing the oocyte with metabolic support and regulatory cues. METHODS PubMed was used to search the MEDLINE database for peer-reviewed original articles and reviews concerning oocyte maturation in mammals. Searches were performed adopting 'oocyte' and 'maturation' as main terms, in association with other keywords expressing concepts relevant to the subject. The most relevant publications, i.e. those concerning major phenomena occurring during oocyte maturation in established experimental models and the human species, were assessed and discussed critically to offer a comprehensive description of the process of oocyte maturation. RESULTS By applying the above described search criteria, 6165 publications were identified, of which 543 were review articles. The number of publications increased steadily from 1974 (n = 7) to 2013 (n = 293). In 2014, from January to the time of submission of this manuscript, 140 original manuscripts and reviews were published. The studies selected for this review extend previous knowledge and shed new and astounding knowledge on oocyte maturation. It has long been known that resumption of meiosis and progression to the metaphase II stage is intrinsic to oocyte maturation, but novel findings have revealed that specific chromatin configurations are indicative of a propensity of the oocyte to resume the meiotic process and acquire developmental competence. Recently, genetic integrity has also been characterized as a factor with important implications for oocyte maturation and quality. Changes occurring in the cytoplasmic compartment are equally fundamental. Microtubules, actin filaments and chromatin not only interact to finalize chromosome segregation, but also crucially co-operate to establish cell asymmetry. This allows polar body extrusion to be accomplished with minimal loss of cytoplasm. The cytoskeleton also orchestrates the rearrangement of organelles in preparation for fertilization. For example, during maturation the distribution of the endoplasmic reticulum undergoes major modifications guided by microtubules and microfilaments to make the oocyte more competent in the generation of intracellular Ca(2+) oscillations that are pivotal for triggering egg activation. Cumulus cells are inherent to the process of oocyte maturation, emitting regulatory signals via direct cell-to-cell contacts and paracrine factors. In addition to nurturing the oocyte with key metabolites, CCs regulate meiotic resumption and modulate the function of the oocyte cytoskeleton. CONCLUSIONS Although the importance of oocyte maturation for the achievement of female meiosis has long been recognized, until recently much less was known of the significance of this process in relation to other fundamental developmental events. Studies on chromatin dynamics and integrity have extended our understanding of female meiosis. Concomitantly, cytoskeletal and organelle changes and the ancillary role of CCs have been better appreciated. This is expected to inspire novel concepts and advances in assisted reproduction technologies, such as the development of novel in vitro maturation systems and the identification of biomarkers of oocyte quality.
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Affiliation(s)
- Giovanni Coticchio
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
| | - Mariabeatrice Dal Canto
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
| | - Mario Mignini Renzini
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
| | - Maria Cristina Guglielmo
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
| | - Fausta Brambillasca
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
| | - Diana Turchi
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
| | - Paola Vittoria Novara
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
| | - Rubens Fadini
- Biogenesi Reproductive Medicine Centre, Istituti Clinici Zucchi, Via Zucchi 24, 20900 Monza, Italy
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Wei Y, Zhang T, Wang YP, Schatten H, Sun QY. Polar bodies in assisted reproductive technology: current progress and future perspectives. Biol Reprod 2014; 92:19. [PMID: 25472922 DOI: 10.1095/biolreprod.114.125575] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
During meiotic cell-cycle progression, unequal divisions take place, resulting in a large oocyte and two diminutive polar bodies. The first polar body contains a subset of bivalent chromosomes, whereas the second polar body contains a haploid set of chromatids. One unique feature of the female gamete is that the polar bodies can provide beneficial information about the genetic background of the oocyte without potentially destroying it. Therefore, polar body biopsies have been applied in preimplantation genetic diagnosis to detect chromosomal or genetic abnormalities that might be inherited by the offspring. Besides the traditional use in preimplantation diagnosis, recent findings suggest additional important roles for polar bodies in assisted reproductive technology. In this paper, we review the new roles of polar bodies in assisted reproductive technology, mainly focusing on single-cell sequencing of the polar body genome to deduce the genomic information of its sibling oocyte and on polar body transfer to prevent the transmission of mtDNA-associated diseases. We also discuss additional potential roles for polar bodies and related key questions in human reproductive health. We believe that further exploration of new roles for polar bodies will contribute to a better understanding of reproductive health and that polar body manipulation and diagnosis will allow production of a greater number of healthy babies.
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Affiliation(s)
- Yanchang Wei
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Teng Zhang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Ya-Peng Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri
| | - Qing-Yuan Sun
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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15
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Hoelker M, Held E, Salilew-Wondim D, Schellander K, Tesfaye D. Molecular signatures of bovine embryo developmental competence. Reprod Fertil Dev 2014; 26:22-36. [PMID: 24305174 DOI: 10.1071/rd13255] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Assessment of the developmental capacity of early bovine embryos is still an obstacle. Therefore, the present paper reviews all current knowledge with respect to morphological criteria and environmental factors that affect embryo quality. The molecular signature of an oocyte or embryo is considered to reflect its quality and to predict its subsequent developmental capacity. Therefore, the primary aim of the present review is to provide an overview of reported correlations between molecular signatures and developmental competence. A secondary aim of this paper is to present some new strategies to enable concomitant evaluation of the molecular signatures of specific embryos and individual developmental capacity.
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Affiliation(s)
- M Hoelker
- Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Alle 15, 53115 Bonn, Germany
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16
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Kahyaoglu I, Demir B, Turkkanı A, Cınar O, Dilbaz S, Dilbaz B, Mollamahmutoglu L. Total fertilization failure: is it the end of the story? J Assist Reprod Genet 2014; 31:1155-60. [PMID: 24962788 DOI: 10.1007/s10815-014-0281-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 06/16/2014] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To study parameters that could predict in-vitro fertilization (IVF) success in patients who experienced total fertilization failure (TFF) with intracytoplasmic sperm injection (ICSI) in their previous cycles. METHODS Cycle characteristics of patients with TFF (Group I, n = 136 cycles), cycles resulting in embryo transfer (ET) following TFF (Group II, n = 36 cycles) and recurrent TFF (Group III, n = 25 cycles) and were studied retrospectively. Demographic features, cycle characteristics of three groups were compared. RESULTS Follicle count measuring 15-17 mm was significantly higher in group II when compared to group I (p = 0.02). Total number of retrieved oocytes and mature oocytes were significantly higher in group II when compared to groups I and III (p = 0.001). Estradiol level at oocyte pick up (OPU) day was significantly higher in group II when compared to group I (p = 0.02). When the characteristics of ET cycles and preceding TFF cycles of the same patient were compared, total number of retrieved oocytes (5.11 ± 0.72 (95% CI 3.69-6.52) vs. 11.44 ± 1.60 (95% CI 5.29-17.59)) and mature oocytes (3.26 ± 3.66 (95% CI 2.04-4.47) vs. 6.92 ± 5.61 (95% CI 5.09-8.75)) were found to be significantly lower in TFF cycles (p = 0.001). Five biochemical and 5 clinical pregnancies occurred while only 2 healthy babies were born, corresponding to a live birth rate 5.5%. CONCLUSIONS Increasing the number of retrieved and mature oocytes may increase the success of fertilization in patients with a history of previous failed fertilization. However, live birth rate is still low in embryo transfer cycles.
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Affiliation(s)
- Inci Kahyaoglu
- Department of Obstetrics and Gynecology, Etlik Zubeyde Hanım Women's Health Teaching and Research Hospital, Etlik Caddesi No:55, Ankara, Turkey
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17
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Mai Z, Lei M, Yu B, Du H, Liu J. The effects of cigarette smoke extract on ovulation, oocyte morphology and ovarian gene expression in mice. PLoS One 2014; 9:e95945. [PMID: 24776817 PMCID: PMC4002431 DOI: 10.1371/journal.pone.0095945] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 04/01/2014] [Indexed: 12/14/2022] Open
Abstract
Cigarette smoking can harm fertility, but the existing research has targeted primarily on ovarian follicles, embryos or sex hormone. In this study, we tested cigarette smoke extract on ovulation, oocyte morphology and ovarian gene expression associated with inhibition of oxidative stress using C57BL/6 mice. Mice in the experimental group were administered a cigarette smoke extract (CSE) solution (2 mg/ml) orally daily, while the blank control group was given dimethylsulfoxide (DMSO). A positive control group (menadione) was used that received an intraperitoneal injection of 15 mg/kg menadione in oil solution daily. We found that the CSE group manifested a reduced diameter of zona pellucida-free oocyte (ZP-free OD) and a morphologically misshapen first polar body (PB). Our results suggest that CSE exposure is associated with a shrink size and poor quality of oocytes. Quitting smoking is a wise choice to ensure good fertility.
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Affiliation(s)
- Zixin Mai
- Department of Reproductive Medicine Center, Key Laboratory for Reproductive Medicine of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ming Lei
- Department of Reproductive Medicine Center, Key Laboratory for Reproductive Medicine of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Bolan Yu
- Department of Reproductive Medicine Center, Key Laboratory for Reproductive Medicine of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Hongzi Du
- Department of Reproductive Medicine Center, Key Laboratory for Reproductive Medicine of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jianqiao Liu
- Department of Reproductive Medicine Center, Key Laboratory for Reproductive Medicine of Guangdong Province, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- * E-mail:
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18
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Ajduk A, Zernicka-Goetz M. Quality control of embryo development. Mol Aspects Med 2013; 34:903-18. [DOI: 10.1016/j.mam.2013.03.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 03/05/2013] [Accepted: 03/19/2013] [Indexed: 11/28/2022]
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Oocyte morphology on day 0 correlates with aneuploidy as detected by polar body biopsy and FISH. Arch Gynecol Obstet 2013; 289:445-50. [PMID: 23880887 DOI: 10.1007/s00404-013-2944-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 06/26/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE For better selection of oocytes and embryos, preimplantation genetic screening (PGS) was introduced. As from the beginning of IVF, morphology was used as selection criteria; we investigated the combination of both. If there was a correlation between phenotype and genotype, invasive PGS might be replaced. METHOD Therefore, 104 cycles with PGS were done by biopsy of the first polar body and FISH with five chromosomes. Morphology of the oocyte was recorded digitally and noted for 12 categories in 4-13 values; evaluation of the chromosomes was noted for five chromosomes in five values. Morphology and genetics were correlated to each other. RESULT Correlations between morphology and genetics for day 0 were found: oocytes with an irregular or dark zona are less probable to have a normal chromosome 13 (80 vs. 53 %, p = 0.001). A medium amount of detritus in the perivitelline space makes it more probable to have a normal chromosome 18 (94 vs. 78 %, p = 0.001). A halo in the cytoplasm makes it less probable to be euploid for chromosome 22 (56 vs. 75 %, p = 0.018). For day 1, pattern "1, 2, 3 and fine" in the pronuclei makes it more probable to be euploid for chromosome 22 (78 vs. 63 %, p = 0.002). CONCLUSION There are correlations between the oocyte genome and its morphology also on day 0. These correlations are not sufficient to replace PGS.
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Jiao ZX, Xu M, Woodruff TK. Age-associated alteration of oocyte-specific gene expression in polar bodies: potential markers of oocyte competence. Fertil Steril 2012; 98:480-6. [PMID: 22633262 DOI: 10.1016/j.fertnstert.2012.04.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 04/22/2012] [Accepted: 04/24/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To confirm that oocyte-specific messenger RNAs are detectable in the polar body (PB) of metaphase II (MII) oocytes and determine the effect of age on oocyte-specific transcript levels. DESIGN Prospective study. SETTING Hospital-based academic research laboratory. ANIMAL(S) CD1 female mice. INTERVENTION(S) Aged (40-50 weeks) and young (7-9 weeks) mice were administered pregnant mare serum gonadotropin (PMSG) and hCG. Oocytes were fertilized in vitro to assess fertilization and developmental competence. The MII oocytes were obtained and first PBs were removed. Messenger RNAs from each PB and its sibling oocyte were reverse transcribed and analyzed by real-time quantitative polymerase chain reaction (PCR). MAIN OUTCOME MEASURE(S) Fertilization and developmental rates and expression of six oocyte-specific genes (Bmp15, Gdf9, H1foo, Nlrp5, Tcl1, and Zp3) in PBs and sibling oocytes from young versus aged mice. RESULT(S) Oocytes from aged mice had lower developmental competence. Four genes (H1foo, Nlrp5, Tcl1, and Zp3) were differentially expressed in aged versus young oocytes. All six transcripts were present in PBs from aged and young mice at lower levels than in the sibling oocytes; transcript levels were lower in aged PBs compared with young PBs. CONCLUSION(S) There is a significant difference in the transcript levels of oocyte-specific genes in aged versus young PB that correlates with age-related decreases in oocyte competence. Differences in gene expression in PB may be potential biomarkers of MII oocyte competence.
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Affiliation(s)
- Ze-Xu Jiao
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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22
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Lasiene K, Lasys V, Glinskyte S, Valanciute A, Vitkus A. Relevance and Methodology for the Morphological Analysis of Oocyte Quality in IVF and ICSI. ACTA ACUST UNITED AC 2011. [DOI: 10.1177/205891581100200102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Oocytes collected from patients following ovarian stimulation exhibit varying qualities. The quality of oocytes has an effect on its subsequent fertilization, developmental competence post-fertilization and the viability of resultant embryos. The aim of this article was to review the morphological criteria devised for assessment of oocyte quality by ordinary light and polarized light microscopy before IVF or ICSI. The parameters employed in the evaluation of oocyte morphology include the appearance of: structure of the cumulus–oocyte complex, oocyte cytoplasm, perivitelline space, zona pellucida, polar body and meiotic spindle.
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Affiliation(s)
- Kristina Lasiene
- Department of Histology and Embryology, Academy of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Vidmantas Lasys
- Department of Anatomy and Physiology, Veterinary Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Sandra Glinskyte
- Department of Anatomy and Physiology, Veterinary Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Angelija Valanciute
- Department of Histology and Embryology, Academy of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Aleksandras Vitkus
- Department of Histology and Embryology, Academy of Medicine, Lithuanian University of Health Sciences, Kaunas, Lithuania
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Fujimoto VY, Browne RW, Bloom MS, Sakkas D, Alikani M. Pathogenesis, developmental consequences, and clinical correlations of human embryo fragmentation. Fertil Steril 2011; 95:1197-204. [DOI: 10.1016/j.fertnstert.2010.11.033] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 11/12/2010] [Accepted: 11/15/2010] [Indexed: 12/20/2022]
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Younis JS, Radin O, Izhaki I, Ben-Ami M. Does first polar body morphology predict oocyte performance during ICSI treatment? J Assist Reprod Genet 2009; 26:561-7. [PMID: 19960239 DOI: 10.1007/s10815-009-9368-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Accepted: 11/09/2009] [Indexed: 10/20/2022] Open
Abstract
PURPOSE To gain insight into the morphology of the first polar body (1 PB) in ICSI patients and to explore whether it could predict mature oocyte viability and performance in this setting. METHODS Seventy two consecutive women planned to perform ICSI treatment were prospectively recruited for this study. All oocytes retrieved underwent evaluation for nuclear maturity and accurate assessment of 1 PB morphology. MII oocytes were cultured in separate groups in each woman in accordance with two different categories of 1 PB morphology. Category A included normal intact round or ovoid 1 PB and category B included abnormal fragmented 1 PB. Each oocyte was followed throughout fertilization, embryo cleavage and embryo transfer. Cycles that reached embryo transfer, were divided into three groups in accordance with 1 PB morphology. Group I included only category A 1 PB embryos, group II included categories A and B 1 PB embryos, whereas group III included only category B 1 PB embryos. RESULTS A total of 687 oocytes were aspirated and 553 MII oocytes underwent ICSI leading to 410 zygotes showing normal fertilization on day one. Three hundred ninety seven embryos cleaved on day two and a total of 176 embryos were replaced into the uterus. Clinical implantation and pregnancy rates were significantly correlated with the morphology of the 1 PB corresponding to 31%, 9% and 2% and 61%, 24% and 5%, in groups I, II and III respectively. CONCLUSIONS Our findings demonstrate that 1 PB morphology is related to mature oocyte viability and it has the potential to predict oocyte performance and pregnancy achievement in infertile women undergoing ICSI treatment.
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Affiliation(s)
- Johnny S Younis
- Reproductive Medicine Unit, Department of Obstetrics & Gynecology, Poriya Medical Center, Tiberias 15208, Israel.
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25
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Navarro PA, de Araújo MM, de Araújo CM, Rocha M, dos Reis R, Martins W. Relationship between first polar body morphology before intracytoplasmic sperm injection and fertilization rate, cleavage rate, and embryo quality. Int J Gynaecol Obstet 2008; 104:226-9. [PMID: 19105998 DOI: 10.1016/j.ijgo.2008.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 11/03/2008] [Accepted: 11/10/2008] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To evaluate the influence of the morphology of the first polar body (PB) on intracytoplasmic sperm injection (ICSI) outcomes. METHODS The morphology of the first PB was assessed in 3177 metaphase II oocytes and classified as: intact and normal size, fragmented, or enlarged size. The rates of fertilization, cleavage, and embryo quality were evaluated on day 2. RESULTS The rates of fertilization, cleavage, and formation of good quality embryos resulting from the insemination of oocytes with an enlarged first PB (20.7%, 18.7%, and 5.0%, respectively) were significantly lower than those for oocytes with an intact first PB of normal size (70.8%, 62.5%, and 19%, respectively) or a fragmented first PB (69.7%, 60.5%, and 17.1%, respectively). Rates did not differ significantly between oocytes with an intact first PB of normal size and oocytes with a fragmented first PB (P>0.05). CONCLUSIONS The presence of an enlarged PB is related to poorer rates of fertilization, cleavage, and top quality embryos. However, identification of first PB fragmentation does not seem to interfere with ICSI outcomes.
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Affiliation(s)
- Paula Andrea Navarro
- Department of Obstetrics and Gynecology, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo, Brazil
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26
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Younis JS, Radin O, Mirsky N, Izhaki I, Majara T, Bar-ami S, Ben-ami M. First polar body and nucleolar precursor body morphology is related to the ovarian reserve of infertile women. Reprod Biomed Online 2008; 16:851-8. [PMID: 18549696 DOI: 10.1016/s1472-6483(10)60152-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study was undertaken in order to gain insight into the morphology of the first polar body (PB1) and the two pronuclei (2PN) in ICSI patients, specifically the nucleolar precursor bodies (NPB). Whether early abnormalities in these structures are related to the ovarian reserve of infertile women was also studied. Eighty consecutive infertile women were prospectively investigated throughout their first ICSI cycles. Basal ovarian reserve studies were performed in all women. Cycles were evaluated with respect to PB1 and 2PN morphology of the transferred embryos. Cycles that had at least one transferred embryo with normal PB1 and 2PN morphology had significantly better basal ovarian reserve parameters compared with cycles in which all transferred embryos had abnormal PB1 and 2PN morphology. Moreover, the normal morphology group performed significantly better throughout the ovarian stimulation, compared with the abnormal morphology group. Furthermore, the clinical implantation and pregnancy rates were significantly higher in the normal compared with the abnormal morphology group, corresponding to 20.7% versus 10.6% and 42.4% versus 18.2%, respectively. The study concluded that the morphology of the PB1 in metaphase II oocytes as well as that of the NPB within the 2PN zygotes seems to be related to the ovarian reserve in infertile women.
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Affiliation(s)
- Johnny S Younis
- Reproductive Medicine Unit, Department of Obstetrics and Gynecology, Poriya Medical Centre, Tiberias, Israel.
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Utsunomiya T, Goto K, Nasu M, Kumasako Y, Araki Y, Yokoo M, Itoh-Sasaki T, Abe H. Evaluating the Quality of Human Embryos with a Measurement of Oxygen Consumption by Scanning Electrochemical Microscopy. ACTA ACUST UNITED AC 2008. [DOI: 10.1274/jmor.25.2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Wang Q, Sun QY. Evaluation of oocyte quality: morphological, cellular and molecular predictors. Reprod Fertil Dev 2007; 19:1-12. [PMID: 17389130 DOI: 10.1071/rd06103] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Mounting evidence that oocyte quality profoundly affects fertilisation an d subsequent embryo development drives the continued search for reliable predictors of oocyte developmental competence. In the present review, we provide an overall summary and analysis of potential criteria that can be used to evaluate oocyte quality. These criteria are specifically classified as morphological and cellular/molecular predictors. Traditional methods for the evaluation of oocyte quality are based on morphological classification of thefollicle, cumulus-oocytecomplex, polar body and/or meiotic spindle. Although the use of morphological characteristics as predictors of oocyte quality is controversial, such a grading system can provide valuable information for the preselection of oocytes with higher developmental competence and, therefore, may maximise embryo developmental outcome. Several intrinsic markers (such as mitochondrial status and glucose-6-phosphate dehydrogenase 1 activity) and extrinsic markers (such as apoptosis of follicular cells and levels of the transforming growth factor-beta superfamily in follicular fluid or serum) have also been reported as useful indicators of oocyte competence and embryo quality. Compared with the morphological parameters, these cellular and molecular predictors of oocyte quality may prove to be more precise and objective, although further studies and refinement of techniques are needed.
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Affiliation(s)
- Qiang Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, China
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Ten J, Mendiola J, Vioque J, de Juan J, Bernabeu R. Donor oocyte dysmorphisms and their influence on fertilization and embryo quality. Reprod Biomed Online 2007; 14:40-8. [PMID: 17207330 DOI: 10.1016/s1472-6483(10)60762-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The aim of this study was to identify predictors of fertilization rate (FR) and embryo quality (EQ) in 126 donor women who underwent 160 intracytoplasmic sperm injection (ICSI) cycles. Main outcome measures were oocyte dysmorphisms (OD) [perivitelline space (normal/large), perivitelline debris (no/yes), oocyte shape (spherical/non-spherical), zona pellucida (normal/abnormal), first polar body morphology (normal/fragmented or irregular), cytoplasmic granularity (normal/excessive), cytoplasmic vacuoles (no/yes) and colour of cytoplasm (normal/dark)], semen source (ejaculated or testicular), donor age, number of days of stimulation, plasma oestradiol concentration (pg/ml) on the day of human chorionic gonadotrophin administration, FR and day 2 EQ. No significant predictors of fertilization were identified. However, the presence of a dark cytoplasm decreased by 83% the likelihood of obtaining good quality embryos (OR=0.17; 95% CI: 0.04-0.74). Oocytes with a larger than normal perivitelline space were associated with 1.8 times higher chance of having good quality embryos (OR=1.80; 95% CI: 1.15-2.80). Patients and ovarian stimulation characteristics evaluated here did not affect FR and EQ. ICSI technique may guarantee good FR in spite of OD; however, certain cytoplasmic anomalies at the oocyte level, such as a dark cytoplasm, could compromise subsequent embryo development.
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Affiliation(s)
- Jorge Ten
- Department of Biology of Reproduction, Instituto Bernabeu, Alicante 03016, Spain.
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Sjöblom P, Menezes J, Cummins L, Mathiyalagan B, Costello MF. Prediction of embryo developmental potential and pregnancy based on early stage morphological characteristics. Fertil Steril 2006; 86:848-61. [PMID: 17027355 DOI: 10.1016/j.fertnstert.2006.03.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2005] [Revised: 03/05/2006] [Accepted: 03/05/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To analyze the association between morphological details at different stages of culture with blastocyst development, with an aim to improve selection for transfer. DESIGN Retrospective audit of data. SETTING Tertiary referral center and university hospital. PATIENT(S) Two hundred sixty-eight couples underwent 357 treatment cycles. INTERVENTION(S) Oocyte pickups for IVF or intracytoplasmic sperm injection (ICSI) after ovarian stimulation. Embryos were individually cultured and examined on days 0-2 for morphological details and developmental characteristics, and selected for transfer, freezing, or further culture. MAIN OUTCOME MEASURES The association of blastocyst development and pregnancy with morphological characteristics. RESULT(S) Five morphological characteristics (appearance of the cytoplasm, pronuclei and nucleoli, cytoplasmic deficit, and developmental rate) showed the strongest association with blastocyst development. By combining information from all days of culture into a cumulative score, prediction was greatly improved, compared to only using day 2 morphology. Cytoplasmic dysmorphisms of the oocyte, including accumulation of smooth endoplasmic reticulum, were associated with poor developmental performance. Differential weighting of these characteristics was included in a new embryo scoring system, which showed a strong correlation with implantation. CONCLUSION(S) Weighting individual morphological characteristics of zygotes and embryos and combining them into a cumulative embryo score can improve selection of embryos for transfer.
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Affiliation(s)
- Peter Sjöblom
- School of Women's and Children's Health, University of New South Wales, Australia.
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31
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Rosen MP, Shen S, Dobson AT, Fujimoto VY, McCulloch CE, Cedars MI. Triploidy formation after intracytoplasmic sperm injection may be a surrogate marker for implantation. Fertil Steril 2006; 85:384-90. [PMID: 16595215 DOI: 10.1016/j.fertnstert.2005.07.1321] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2005] [Revised: 07/27/2005] [Accepted: 07/27/2005] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Triploidy after intracytoplasmic sperm injection (ICSI) is due mostly to retention of the second polar body. Our interest was to determine the predictors of triploidy and to determine whether the presence of triploidy can serve as a surrogate marker of implantation for the remaining cohort of zygotes. DESIGN Cohort study. SETTING Academic research center. PATIENT(S) Infertile couples undergoing IVF/ICSI. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Triploid zygote (3PN) rate, implantation rate. RESULT(S) The 3PN rate is a significant predictor of implantation rate for the remaining cohort of zygotes. The starting and total dose of gonadotropins administered and the total days of stimulation are independent predictors of the 3PN rate. CONCLUSION(S) In couples with a normal semen analysis undergoing IVF/ICSI, the 3PN rate may serve as a surrogate marker of oocyte quality and may be altered by adjusting the stimulation protocol.
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Affiliation(s)
- Mitchell P Rosen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, California, USA
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32
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Ebner T, Moser M, Tews G. Is oocyte morphology prognostic of embryo developmental potential after ICSI? Reprod Biomed Online 2006; 12:507-12. [PMID: 16740226 DOI: 10.1016/s1472-6483(10)62006-8] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Metaphase II-stage oocytes collected from patients following ovarian stimulation show varying qualities. Both nuclear and cytoplasmic maturation have to be completed in a co-ordinated mode to ensure optimal conditions for subsequent fertilization. Disturbances or asynchrony of these processes may result in different morphological abnormalities, depending on whether nuclear or cytoplasmic maturation has been affected. In this respect it has been suggested that dysmorphic features occurring early in meiotic maturation may be associated with a higher frequency of aneuploidy and fertilization failure, while those occurring late in maturation may cause a higher incidence of developmental failure. In fact, more than half of the gametes collected show morphological abnormalities, some of which seem to be correlated with an impaired outcome (e.g. aggregation of endoplasmic reticulum, vacuolization, increased ooplasmic viscosity, giant eggs). Therefore, it is strongly recommended to include oocyte quality in all scoring systems applied in IVF laboratories.
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Affiliation(s)
- Thomas Ebner
- Women's General Hospital, IVF-Unit, Lederergasse 47, A-4010 Linz, Upper Austria, Austria.
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Familiari G, Heyn R, Relucenti M, Nottola SA, Sathananthan AH. Ultrastructural Dynamics of Human Reproduction, from Ovulation to Fertilization and Early Embryo Development1. ACTA ACUST UNITED AC 2006; 249:53-141. [PMID: 16697282 DOI: 10.1016/s0074-7696(06)49002-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
This study describes the updated, fine structure of human gametes, the human fertilization process, and human embryos, mainly derived from assisted reproductive technology (ART). As clearly shown, the ultrastructure of human reproduction is a peculiar multistep process, which differs in part from that of other mammalian models, having some unique features. Particular attention has been devoted to the (1) sperm ultrastructure, likely "Tygerberg (Kruger) strict morphology criteria"; (2) mature oocyte, in which the MII spindle is barrel shaped, anastral, and lacking centrioles; (3) three-dimensional microarchitecture of the zona pellucida with its unique supramolecular filamentous organization; (4) sperm-egg interactions with the peculiarity of the sperm centrosome that activates the egg and organizes the sperm aster and mitotic spindles of the embryo; and (5) presence of viable cumulus cells whose metabolic activity is closely related to egg and embryo behavior in in vitro as well as in vivo conditions, in a sort of extraovarian "microfollicular unit." Even if the ultrastructural morphodynamic features of human fertilization are well understood, our knowledge about in vivo fertilization is still very limited and the complex sequence of in vivo biological steps involved in human reproduction is only partially reproduced in current ART procedures.
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Affiliation(s)
- Giuseppe Familiari
- Laboratory of Electron Microscopy, Pietro M. Motta Department of Anatomy, University of Rome, La Sapienza, 00161 Rome, Italy
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Abstract
Assessment of oocyte morphology is a difficult task, since underlying mechanisms that change the appearance of the oocyte are multifactorial and complex. Significant morphological variations are known to exist among oocytes that may affect the developmental competence and implantation potential of the derived embryo. Morphological variations of the oocyte may result from intrinsic factors such as age and genetic defects or extrinsic factors such as stimulation protocols, culture conditions, and nutrition. The effect of these morphological variations of the oocyte on embryo development and implantation, however, is not conclusively defined because of methodological flaws inherent to most of the studies in the literature. This review will mainly discuss morphological markers of oocyte quality/viability in relation to the oocyte morphology and attempt to clarify whether morphological evaluation of the oocyte can be utilized for predicting the implantation potential of the derived embryo.
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Affiliation(s)
- Basak Balaban
- Assisted Reproduction Unit, American Hospital of Istanbul, Guzelbahce sok no. 20, 34365 Nisantasi, Turkey.
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De Santis L, Cino I, Rabellotti E, Calzi F, Persico P, Borini A, Coticchio G. Polar body morphology and spindle imaging as predictors of oocyte quality. Reprod Biomed Online 2005; 11:36-42. [PMID: 16102284 DOI: 10.1016/s1472-6483(10)61296-5] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
It has been suggested that first polar body (PBI) morphology reflects oocyte competence. Oocytes with an intact normal-sized PBI have been described as generating better day 2 embryos, higher blastocyst yield, and increased pregnancy and implantation rates. In other studies, PBI morphology was found to be unrelated to fertilization rate, embryo quality, and blastocyst formation. In a prospective analysis, the predictive value of the PBI was investigated by comparing the development of oocytes retrieved from intracytoplasmic sperm injection patients and displaying different PBI morphology, classified according to the following characteristics: normal size and smooth surface (I), fragmented (II), rough surface (III), or large size (IV). Fertilization rates were 59, 57, 64 and 60% respectively. No significant differences were found between the various groups. The proportions of high quality (grade A) day 2 embryos were also comparable among groups I-III (14, 12 and 17% respectively), while the low number of grade A embryos in group IV (two embryos) did not allow comparison with the other classes. These data do not suggest that PBI selection can contribute to identification of embryos with high developmental ability. In order to establish alternative criteria for oocyte selection, a metaphase II (MII) spindle analysis was also conducted via Polscope. In oocytes of patients of different age, spindle retardance (which reflects the high order and density of microtubules) was compared with parameters of embryo development. In aged patients, a trend was observed between low retardance and poor embryo quality, although in general the association between retardance and oocyte developmental performance did not reach statistical significance.
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Affiliation(s)
- Lucia De Santis
- Vita-Salute University, H S. Raffaele, IVF Unit, Milan, Italy.
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Rienzi L, Ubaldi F, Iacobelli M, Romano S, Minasi MG, Ferrero S, Sapienza F, Baroni E, Greco E. Significance of morphological attributes of the early embryo. Reprod Biomed Online 2005; 10:669-81. [PMID: 15949228 DOI: 10.1016/s1472-6483(10)61676-8] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There are many morphological transformations during development of human embryos that mainly involve phenomena that can be easily assessed in living embryos by simple non-invasive microscopical observation. A clear correlation between pronuclear morphology and the ability of the resulting embryo to continue developing and to implant has been described. There is also general agreement that a positive relationship exists between early embryo morphology and implantation rate. The parameters classically involved in embryo evaluation are: cleavage rate, blastomere symmetry, cytoplasmic appearance, extent of fragmentation and blastomere nuclear status. In this paper, morphological features that have been related to embryo developmental potential are described. Furthermore, the ability of a cumulative classification scheme developed in the laboratory to predict blastocyst formation and implantation is analysed.
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Affiliation(s)
- Laura Rienzi
- Centre for Reproductive Medicine, European Hospital, Via Portuense 700, 00149 Rome, Italy.
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Borini A, Lagalla C, Cattoli M, Sereni E, Sciajno R, Flamigni C, Coticchio G. Predictive factors for embryo implantation potential. Reprod Biomed Online 2005; 10:653-68. [PMID: 15949227 DOI: 10.1016/s1472-6483(10)61675-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In spite of recent improvements in IVF, pregnancy rates have not increased significantly and one of the major problems remains the high multiple pregnancy rate. Better criteria are therefore necessary to establish the viability of a transferable embryo. Early prognosis of the developmental fate of the oocyte would help in selecting the best embryos to transfer, but non-invasive selection at the oocyte stage (extracytoplasmic and intracytoplasmic morphology) has proved to be of little prognostic value. Recently, it has been shown that follicular vascularization appears to be predictive of oocyte developmental fate, making it a good first-step approach for selection. Observation of pronuclei patterns at the zygote stage appears to offer an additional prognostic tool, correlating well with IVF outcome. Morphological evaluation of the embryo at days 2-3 remains the most used and valid method of selection, even though it is not sufficient to select embryos with the higher implantation potential. Blastocyst culture is another possible strategy for selecting the best embryos with reduced risk of aneuploidies, though not all major chromosomal aberrations are excluded by prolonged in-vitro culture. In summary, selecting the best embryo for transfer is a decision that should be based on choices made during the different stages of assisted reproductive technologies.
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Affiliation(s)
- Andrea Borini
- Tecnobios Procreazione, Via Dante 15, Bologna 40125, Italy.
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Germond M, Primi MP, Urner F, Chanson A, Wirthner D, Senn A. Number of transferred embryos: how to reduce multiple pregnancies. Ann N Y Acad Sci 2005; 1034:93-100. [PMID: 15731302 DOI: 10.1196/annals.1335.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Because the diagnostic tools for predicting whether an early cleavage stage embryo can lead to a viable pregnancy are still elusive, transfer of more than one embryo remains quite common. However, the only way to reduce multiple pregnancies, considered as the main adverse effect of assisted reproductive technology, is to transfer a single embryo. In countries such as Switzerland and Germany, the law allows cryopreservation only at the 2-pronuclear stage. This restricts considerably the possibility of selecting the embryos to be transferred. Therefore, a good cryopreservation program at the 2-pronuclear stage is an essential tool to optimize the efficiency of in vitro fertilization (IVF). We therefore recommend the Cumulated Singleton Delivery Rate (CUSIDERA) as a measure of standard IVF efficiency. This rate averages approximately 23.5% when calculated over the last 10 years in our unit and reaches a value above 35% for patients with more than 10 zygotes. Elective single-embryo transfers and the decrease of iatrogenic multiple pregnancies in IVF remain dependent on better prognostic tools for the appropriate selection of patients, gametes, and zygotes.
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Affiliation(s)
- Marc Germond
- Unité de Médecine de la Reproduction, Maternité, CHUV, CH-1011 Lausanne, Switzerland.
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Coticchio G, Sereni E, Serrao L, Mazzone S, Iadarola I, Borini A. What Criteria for the Definition of Oocyte Quality? Ann N Y Acad Sci 2004; 1034:132-44. [PMID: 15731306 DOI: 10.1196/annals.1335.016] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Although the spermatozoon provides an essential contribution to the generation of a new individual, the developmental fate of the embryo is principally dictated by the oocyte. Oocyte competencies are acquired throughout oogenesis, via the interaction with somatic cells. The ability to reinitiate the meiotic process and undergo preimplantation development is progressively determined during the antral phase. It is known that these changes involve the nuclear and cytoplasmic compartments, respectively, but the underlying cellular and molecular mechanisms are still poorly understood. Analysis of various aspects of oocyte morphology (cytoplasm, zona pellucida, and polar body) via conventional phase-contrast microscopy has generated contrasting evidence on the possibility of establishing reliable criteria for the prediction of developmental potential. The introduction of a newly developed microscopy technique based on the detection of polarized light generated by birefringent cell structures has offered the possibility of visualizing noninvasively the meiotic spindle, whose presence is critical for fertilization and later developmental stages. However, further studies are needed to standardize and interpret the information accessible through such a technique. Although unable to preserve cell viability and therefore provide a method by which to select oocytes with superior developmental competence, invasive techniques can make a fundamental contribution to defining objective criteria of oocyte quality. In particular, immunofluorescence analysis, which is able to identify critical anomalies of the meiotic spindle and cytoskeleton organization that can account for oocyte quality, is an important method for assessing the efficiency of in vitro maturation systems.
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Ciotti PM, Notarangelo L, Morselli-Labate AM, Felletti V, Porcu E, Venturoli S. First polar body morphology before ICSI is not related to embryo quality or pregnancy rate. Hum Reprod 2004; 19:2334-9. [PMID: 15347596 DOI: 10.1093/humrep/deh433] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The aim of this study was to analyse the relationship between the first polar body (1st PB) morphology and the fertilization rate, cleavage rate, embryo quality, pregnancy and implantation rate. METHODS This was a retrospective study on 167 consecutive cycles undergoing assisted reproduction with ICSI. The 1st PB morphology was evaluated at the moment of ICSI in the 596 injected oocytes and it was coded as intact or fragmented. The fertilization rate, cleavage rate, embryo quality (three grades), pregnancy rate, implantation rate and the time elapsed between oocyte retrieval and ICSI were evaluated. The 1st PB morphology was checked twice (denudation and ICSI) in a random sample of 180 oocytes in order to verify the effect of the in vitro culture. RESULTS No significant relationship was found between the 1st PB morphology and the fertilization rate (P=0.703), cleavage rate (P=0.055), embryo quality (P=0.673), pregnancy rate (P=0.201) and implantation rate (P=0.511). A significant positive relationship (P=0.006) was found between the frequency of the 1st PB fragmentation and the time elapsed between denudation and ICSI. The pregnancy rate was significantly higher (P=0.008) when oocytes were injected between 5 and 7 h after retrieval rather than earlier or later. CONCLUSIONS Our data suggest that the embryo quality, pregnancy rate and implantation rate are not related to the 1st PB fragmentation. The time which elapses between the oocyte retrieval and ICSI should be maintained at approximately 6 h in order to obtain optimal results.
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Affiliation(s)
- P M Ciotti
- Infertility and IVF Centre, Human Reproductive Medicine Unit, Alma Mater Studiorum, University of Bologna, Via Massarenti 13, 40138 Bologna, Italy.
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Abstract
The enormous volume of the fertilized egg is attributable to the suppression of cleavage during oocyte growth and the unequal cleavages during the first and second meiotic divisions. The two products of these divisions are the diminutive polar bodies (PB), which contain a redundant set of chromosomes/chromatids plus cytoplasmic organelles. The PB have strictly limited but differential life spans; while viable they possess the genetic potential to support normal embryonic development after transfer to a cytoplast. In addition to the theoretical possibility of using this non-cloning technique to generate more embryos, polar bodies can be used for genetic testing. By cytogenetic analysis of both PB using fluorescent in-situ hybridization (FISH) or chromosome painting, partial or full chromosomal status in the oocyte can be predicted; this approach finds particular application for women of advanced reproductive age as well as with maternally inherited translocations and single gene defects. By studying both of the PB, potential problems of interpretation arising from allele dropout can be reduced; a heterozygous first polar body provides the least ambiguous result. Mitochondria segregate randomly during meiotic cleavages providing an opportunity also to use the PB to screen for mitochondrial mutations and deletions. Thus, the PB can serve useful diagnostic purposes, especially where pre-fertilization screening or avoidance of embryo biopsy is desirable.
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Affiliation(s)
- S A Gitlin
- The Jones Institute for Reproductive Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, 601 Colley Avenue, Norfolk, VA 23507, USA.
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Abstract
Many strategies have been proposed for the selection of viable embryos for transfer in human assisted reproduction. These have included morphological scoring criteria for day 1, 2, 3 and 5 embryos or combinations of these. Other strategies have used predictors such as timing of certain key events, as with early cleavage to the 2-cell, development to the 8-cell stage or patterns of fragmentation. All have shown some correlations with implantation. However, the overall success of these methods is still limited, with over 50% of all transferred embryos failing to implant. The use of pronuclear oocyte morphology has shown correlations with implantation and development to the blastocyst stage. The key aspects of pronuclear scoring, namely the presence of a cytoplasmic halo, the orientation of the nuclei in relation to the polar bodies and the size, number and pattern of distribution of nucleolar precursor bodies (NPB) in the nuclei were related to day 2,3 and 5 development, rate of development and day 3 and 5 morphology in a retrospective study. The pattern of the NPB or Z-score and the presence/absence of a halo had a significant effect on the rate of development on day 3 and day 5 and on the overall embryo morphology score. Low Z-score resulted in slow development, poor blastocyst formation and low morphology scores. The absence of a halo also resulted in slow and poor development, poor morphology, increased fragmentation and increased numbers of poor Z-scored embryos. The use of PN scoring can help predict embryos that have poor developmental potential, aid in early selection and may indicate the health of the oocyte.
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Affiliation(s)
- Lynette Scott
- University of Washington Medical School, Department of Obstetrics and Gynecology, Fertility and Endocrinology Centre, 4225 Roosevelt Way, NE Seattle, WA 98105, USA.
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