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Budrewicz J, Chavez SL. Insights into embryonic chromosomal instability: mechanisms of DNA elimination during mammalian preimplantation development. Front Cell Dev Biol 2024; 12:1344092. [PMID: 38374891 PMCID: PMC10875028 DOI: 10.3389/fcell.2024.1344092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 01/15/2024] [Indexed: 02/21/2024] Open
Abstract
Mammalian preimplantation embryos often contend with aneuploidy that arose either by the inheritance of meiotic errors from the gametes, or from mitotic mis-segregation events that occurred following fertilization. Regardless of the origin, mis-segregated chromosomes become encapsulated in micronuclei (MN) that are spatially isolated from the main nucleus. Much of our knowledge of MN formation comes from dividing somatic cells during tumorigenesis, but the error-prone cleavage-stage of early embryogenesis is fundamentally different. One unique aspect is that cellular fragmentation (CF), whereby small subcellular bodies pinch off embryonic blastomeres, is frequently observed. CF has been detected in both in vitro and in vivo-derived embryos and likely represents a response to chromosome mis-segregation since it only appears after MN formation. There are multiple fates for MN, including sequestration into CFs, but the molecular mechanism(s) by which this occurs remains unclear. Due to nuclear envelope rupture, the chromosomal material contained within MN and CFs becomes susceptible to double stranded-DNA breaks. Despite this damage, embryos may still progress to the blastocyst stage and exclude chromosome-containing CFs, as well as non-dividing aneuploid blastomeres, from participating in further development. Whether these are attempts to rectify MN formation or eliminate embryos with poor implantation potential is unknown and this review will discuss the potential implications of DNA removal by CF/blastomere exclusion. We will also extrapolate what is known about the intracellular pathways mediating MN formation and rupture in somatic cells to preimplantation embryogenesis and how nuclear budding and DNA release into the cytoplasm may impact overall development.
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Affiliation(s)
- Jacqueline Budrewicz
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Shawn L. Chavez
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, United States
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, United States
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR, United States
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Bredbacka P, Capalbo A, Kananen K, Picchetta L, Tomás C. Healthy live birth following embryo transfer of a blastocyst of tetrapronuclear (4PN) origin: a case report. Hum Reprod 2023; 38:1700-1704. [PMID: 37528053 DOI: 10.1093/humrep/dead151] [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: 03/13/2023] [Revised: 05/29/2023] [Indexed: 08/03/2023] Open
Abstract
During IVF treatments, normal fertilization is generally evidenced by the appearance of two pronuclei, one arising from the oocyte and the other from the male gamete. Embryos derived from zygotes with a pronuclei number other than two are assumed to possess a ploidy abnormality and their transfer is usually avoided owing to increased risk of implantation failure, miscarriage, and molar pregnancies. Nonetheless, the inclusion of genotyping data in preimplantation genetic testing has revealed that a normal diploid configuration is possible in embryos deriving from zygotes with an abnormal pronuclei number such as tripronuclear and one pronucleus. Here, we present a one-of-a-kind transfer of a tetrapronuclear-derived embryo that was discovered to be diploid and negative for other whole chromosome or segmental aneuploidies during preimplantation genetic testing using a targeted next-generation sequencing approach. The transfer resulted in the live birth of a healthy infant who is now 4 years old and has no apparent health or developmental impairments.
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Heydari L, Khalili MA, Rahimi AA, Shakeri F. Human embryos derived from first polar body nuclear transfer exhibit comparatively abnormal morphokinetics during development. Clin Exp Reprod Med 2023; 50:177-184. [PMID: 37643831 PMCID: PMC10477411 DOI: 10.5653/cerm.2023.05939] [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: 01/31/2023] [Revised: 05/25/2023] [Accepted: 06/10/2023] [Indexed: 08/31/2023] Open
Abstract
OBJECTIVE Reconstructed oocytes after polar body genome transfer constitute a potential therapeutic option for patients with a history of embryo fragmentation and advanced maternal age. However, the rescue of genetic material from the first polar body (PB1) through introduction into the donor cytoplasm is not yet ready for clinical application. METHODS Eighty-five oocytes were obtained following in vitro maturation (IVM) and divided into two groups: PB1 nuclear transfer (PB1NT; n=54) and control (n=31). Following enucleation and PB1 genomic transfer, PB1 fusion was assessed. Subsequently, all fused oocytes underwent intracytoplasmic sperm injection (ICSI) and were cultured in an incubator under a time-lapse monitoring system to evaluate fertilization, embryonic morphokinetic parameters, and cleavage patterns. RESULTS Following enucleation and fusion, 77.14% of oocytes survived, and 92.59% of polar bodies (PBs) fused. However, the normal fertilization rate was lower in the PB1NT group than in the control group (56.41% vs. 92%, p=0.002). No significant differences were observed in embryo kinetics between the groups, but a significant difference was detected in embryo developmental arrest after the four-cell stage, along with abnormal cleavage division in the PB1NT group. This was followed by significant between-group differences in the implantation potential rate and euploidy status. Most embryos in the PB1NT group had at least one abnormal cleavage division (93.3%, p=0.001). CONCLUSION Fresh PB1NT oocytes successfully produced normal zygotes following PB fusion and ICSI in IVM oocytes. However, this was accompanied by low efficiency in developing into cleavage embryos, along with an increase in abnormal cleavage patterns.
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Affiliation(s)
- Leila Heydari
- Research and Clinical Center for Infertility, Yazd Reproductive Science Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Ali Khalili
- Research and Clinical Center for Infertility, Yazd Reproductive Science Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Azam Agha Rahimi
- Research and Clinical Center for Infertility, Yazd Reproductive Science Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Fatemeh Shakeri
- Research and Clinical Center for Infertility, Yazd Reproductive Science Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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Helosvuori E, Homanen R. When craft kicks back: Embryo culture as knowledge production in the context of the transnational fertility industry. SOCIAL STUDIES OF SCIENCE 2022; 52:425-446. [PMID: 35297697 PMCID: PMC9109581 DOI: 10.1177/03063127221083869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The multibillion-dollar fertility industry promotes standardization in in vitro fertilization laboratories. Transnational pharmaceutical and biotechnological giants distribute a wide range of fertility products, from embryo culture mediums and incubator technologies to add-ons such as time-lapse embryo monitoring. These technologies are designed to standardize and automate knowledge production regarding embryonic viability. More effective knowledge production enables the more effective selection of embryos for transfer, which in turn leads to more future babies and enables economic scaling-up. Drawing on two multi-sited ethnographic studies at eight fertility clinics in Finland during 2013-2020, this article discusses how knowledge about embryos is produced in the processes and practices of embryo culture. We argue that automation and standardization in clinical practice are not always perceived as economically desirable. Sometimes standard technologies do not replace hands-on knowledge production, although they may transform it. The technologies are also perceived as modifying the object of knowledge itself in undesired or unnecessary ways. In such cases, concerns are raised regarding the best interests of patients, embryos and future babies, who might be better served by masterful laboratory craftwork. We conclude that embryo culture is not only a site of knowledge production - one that aims to make babies and parents through standard and craftwork knowledge practices - but also a site of multiple bio-economies of assisted reproduction, some of which resist automation and standardization.
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Cellular and Molecular Nature of Fragmentation of Human Embryos. Int J Mol Sci 2022; 23:ijms23031349. [PMID: 35163271 PMCID: PMC8836137 DOI: 10.3390/ijms23031349] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 02/01/2023] Open
Abstract
Embryo fragmentation represents a phenomenon generally characterized by the presence of membrane-bound extracellular cytoplasm into the perivitelline space. Recent evidence supports the cellular and molecular heterogeneity of embryo fragments. In this narrative review, we described the different embryo fragment-like cellular structures in their morphology, molecular content, and supposed function and have reported the proposed theories on their origin over the years. We identified articles related to characterization of embryo fragmentation with a specific literature search string. The occurrence of embryo fragmentation has been related to various mechanisms, of which the most studied are apoptotic cell death, membrane compartmentalization of altered DNA, cytoskeletal disorders, and vesicle formation. These phenomena are thought to result in the extrusion of entire blastomeres, release of apoptotic bodies and other vesicles, and micronuclei formation. Different patterns of fragmentation may have different etiologies and effects on embryo competence. Removal of fragments from the embryo before embryo transfer with the aim to improve implantation potential should be reconsidered on the basis of the present observations
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Brooks KE, Daughtry BL, Metcalf E, Masterson K, Battaglia D, Gao L, Park B, Chavez SL. Assessing equine embryo developmental competency by time-lapse image analysis. Reprod Fertil Dev 2020; 31:1840-1850. [PMID: 31759400 DOI: 10.1071/rd19254] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/31/2019] [Indexed: 01/03/2023] Open
Abstract
The timing of early mitotic events during preimplantation embryo development is important for subsequent embryogenesis in many mammalian species, including mouse and human, but, to date, no study has closely examined mitotic timing in equine embryos from oocytes obtained by ovum pick-up. Here, cumulus-oocyte complexes were collected by transvaginal follicular aspiration, matured invitro and fertilised via intracytoplasmic sperm injection. Each fertilised oocyte was cultured up to the blastocyst stage and monitored by time-lapse imaging for the measurement of cell cycle intervals and identification of morphological criteria indicative of developmental potential. Of the 56 fertilised oocytes, 35 initiated mitosis and 11 progressed to the blastocyst stage. Analysis of the first three mitotic divisions in embryos that formed blastocysts determined that typical blastocyst timing (median±IQR) is 30.0±17.5min, 8.8±1.7h and 0.6±1.4h respectively. Frequent cellular fragmentation, multipolar divisions and blastomere exclusion suggested that equine embryos likely contend with a high incidence of chromosomal missegregation. Indeed, chromosome-containing micronuclei and multinuclei with extensive DNA damage were observed throughout preimplantation embryogenesis. This indicates that time-lapse image analysis may be used as a non-invasive method to assess equine embryo quality in future studies.
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Affiliation(s)
- Kelsey E Brooks
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR 97006, USA
| | - Brittany L Daughtry
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR 97006, USA; and Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University School of Medicine, Portland, OR 97239, USA
| | - Elizabeth Metcalf
- Department of Obstetrics and Gynecology, Oregon Health and Science University School of Medicine, Portland, OR 97239, USA
| | - Keith Masterson
- Department of Obstetrics and Gynecology, Oregon Health and Science University School of Medicine, Portland, OR 97239, USA
| | - David Battaglia
- Department of Obstetrics and Gynecology, Oregon Health and Science University School of Medicine, Portland, OR 97239, USA
| | - Lina Gao
- Bioinformatics and Biostatistics Core, Oregon National Primate Research Center, Beaverton, OR 97006, USA
| | - Byung Park
- Bioinformatics and Biostatistics Core, Oregon National Primate Research Center, Beaverton, OR 97006, USA
| | - Shawn L Chavez
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR 97006, USA; and Department of Obstetrics and Gynecology, Oregon Health and Science University School of Medicine, Portland, OR 97239, USA; and Department of Physiology and Pharmacology, Oregon Health and Science University School of Medicine, Portland, OR 97239, USA; and Department of Biomedical Engineering, Oregon Health and Science University School of Medicine, Portland, OR 97239, USA; and Corresponding author.
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The mechanisms and clinical application of mosaicism in preimplantation embryos. J Assist Reprod Genet 2019; 37:497-508. [PMID: 31838629 DOI: 10.1007/s10815-019-01656-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/05/2019] [Indexed: 02/08/2023] Open
Abstract
Embryos containing distinct cell lines are referred to as mosaic embryos, which are considered to be caused by mitotic errors in chromosome segregation during preimplantation development. As the accuracy and resolution of detection techniques improve, more and more mosaic embryos were identified recently. The impacts of mosaic embryos on survival and potential pregnancy outcome have been reported to be diverse in different studies. Because of the universality and clinical significance of mosaicism, it is essential to unravel the mechanisms and consequences with regard to this phenomenon in human pre- and post-implantation embryos. The purpose of this review is to explore the mechanisms, causes of mosaicism, and the development of pre- and post-implantation mosaic embryos in the light of recent emerging data, with the aim of providing new references for clinical applications.
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Bishop CV, Reiter TE, Erikson DW, Hanna CB, Daughtry BL, Chavez SL, Hennebold JD, Stouffer RL. Chronically elevated androgen and/or consumption of a Western-style diet impairs oocyte quality and granulosa cell function in the nonhuman primate periovulatory follicle. J Assist Reprod Genet 2019; 36:1497-1511. [PMID: 31187329 DOI: 10.1007/s10815-019-01497-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/24/2019] [Indexed: 02/06/2023] Open
Abstract
PURPOSE To investigate the impact of chronically elevated androgens in the presence and absence of an obesogenic diet on oocyte quality in the naturally selected primate periovulatory follicle. METHODS Rhesus macaques were treated using a 2-by-2 factorial design (n = 10/treatment) near the onset of menarche with implants containing either cholesterol (C) or testosterone (T, 4-5-fold increase above C) and a standard or "Western-style" diet alone (WSD) or in combination (T+WSD). Following ~ 3.5 years of treatment, females underwent controlled ovulation (COv, n = 7-10/treatment) cycles, and contents of the naturally selected periovulatory follicle were aspirated. Follicular fluid (FF) was analyzed for cytokines, chemokines, growth factors, and steroids. RNA was extracted from luteinizing granulosa cells (LGCs) and assessed by RNA-seq. RESULTS Only healthy, metaphase (M) I/II-stage oocytes (100%) were retrieved in the C group, whereas several degenerated oocytes were recovered in other groups (33-43% of T, WSD, and T+WSD samples). Levels of two chemokines and one growth factor were reduced (p < 0.04) in FF of follicles with a MI/MII oocyte in WSD+T (CCL11) or T and WSD+T groups (CCL2 and FGF2) compared to C and/or WSD. Intrafollicular cortisol was elevated in T compared to C follicles (p < 0.02). Changes in the expression pattern of 640+ gene products were detected in LGC samples from follicles with degenerated versus MI/MII-stage oocytes. Pathway analysis on RNAs altered by T and/or WSD found enrichment of genes mapping to steroidogenic and immune cell pathways. CONCLUSIONS Female primates experiencing hyperandrogenemia and/or consuming a WSD exhibit an altered intrafollicular microenvironment and reduced oocyte quality/competency, despite displaying menstrual cyclicity.
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Affiliation(s)
- Cecily V Bishop
- Division of Reproductive & Developmental Sciences, Oregon Health & Science University, Beaverton, OR, USA. .,Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, OR, 97331, USA.
| | - Taylor E Reiter
- Division of Reproductive & Developmental Sciences, Oregon Health & Science University, Beaverton, OR, USA
| | - David W Erikson
- Endocrine Technologies Core, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, USA
| | - Carol B Hanna
- Division of Reproductive & Developmental Sciences, Oregon Health & Science University, Beaverton, OR, USA
| | - Brittany L Daughtry
- Division of Reproductive & Developmental Sciences, Oregon Health & Science University, Beaverton, OR, USA
| | - Shawn L Chavez
- Division of Reproductive & Developmental Sciences, Oregon Health & Science University, Beaverton, OR, USA.,Department of Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR, 97239, USA.,Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Jon D Hennebold
- Division of Reproductive & Developmental Sciences, Oregon Health & Science University, Beaverton, OR, USA.,Department of Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR, 97239, USA.,Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Richard L Stouffer
- Division of Reproductive & Developmental Sciences, Oregon Health & Science University, Beaverton, OR, USA.,Department of Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR, 97239, USA
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