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Han Q, Ma R, Liu N. Epigenetic reprogramming in the transition from pluripotency to totipotency. J Cell Physiol 2024. [PMID: 38375873 DOI: 10.1002/jcp.31222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/08/2024] [Accepted: 02/05/2024] [Indexed: 02/21/2024]
Abstract
Mammalian development commences with the zygote, which can differentiate into both embryonic and extraembryonic tissues, a capability known as totipotency. Only the zygote and embryos around zygotic genome activation (ZGA) (two-cell embryo stage in mice and eight-cell embryo in humans) are totipotent cells. Epigenetic modifications undergo extremely extensive changes during the acquisition of totipotency and subsequent development of differentiation. However, the underlying molecular mechanisms remain elusive. Recently, the discovery of mouse two-cell embryo-like cells, human eight-cell embryo-like cells, extended pluripotent stem cells and totipotent-like stem cells with extra-embryonic developmental potential has greatly expanded our understanding of totipotency. Experiments with these in vitro models have led to insights into epigenetic changes in the reprogramming of pluri-to-totipotency, which have informed the exploration of preimplantation development. In this review, we highlight the recent findings in understanding the mechanisms of epigenetic remodeling during totipotency capture, including RNA splicing, DNA methylation, chromatin configuration, histone modifications, and nuclear organization.
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Affiliation(s)
- Qingsheng Han
- School of Medicine, Nankai University, Tianjin, China
| | - Ru Ma
- School of Medicine, Nankai University, Tianjin, China
| | - Na Liu
- School of Medicine, Nankai University, Tianjin, China
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Bora P, Gahurova L, Hauserova A, Stiborova M, Collier R, Potěšil D, Zdráhal Z, Bruce AW. DDX21 is a p38-MAPK-sensitive nucleolar protein necessary for mouse preimplantation embryo development and cell-fate specification. Open Biol 2021; 11:210092. [PMID: 34255976 PMCID: PMC8277471 DOI: 10.1098/rsob.210092] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Successful navigation of the mouse preimplantation stages of development, during which three distinct blastocyst lineages are derived, represents a prerequisite for continued development. We previously identified a role for p38-mitogen-activated kinases (p38-MAPK) regulating blastocyst inner cell mass (ICM) cell fate, specifically primitive endoderm (PrE) differentiation, that is intimately linked to rRNA precursor processing, polysome formation and protein translation regulation. Here, we develop this work by assaying the role of DEAD-box RNA helicase 21 (DDX21), a known regulator of rRNA processing, in the context of p38-MAPK regulation of preimplantation mouse embryo development. We show nuclear DDX21 protein is robustly expressed from the 16-cell stage, becoming exclusively nucleolar during blastocyst maturation, a localization dependent on active p38-MAPK. siRNA-mediated clonal Ddx21 knockdown within developing embryos is associated with profound cell-autonomous and non-autonomous proliferation defects and reduced blastocyst volume, by the equivalent peri-implantation blastocyst stage. Moreover, ICM residing Ddx21 knockdown clones express the EPI marker NANOG but rarely express the PrE differentiation marker GATA4. These data contribute further significance to the emerging importance of lineage-specific translation regulation, as identified for p38-MAPK, during mouse preimplantation development.
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Affiliation(s)
- Pablo Bora
- Laboratory of Early Mammalian Developmental Biology (LEMDB), Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic
| | - Lenka Gahurova
- Laboratory of Early Mammalian Developmental Biology (LEMDB), Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic.,Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics, CAS, Rumburská 89, 27721 Liběchov, Czech Republic
| | - Andrea Hauserova
- Laboratory of Early Mammalian Developmental Biology (LEMDB), Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic
| | - Martina Stiborova
- Laboratory of Early Mammalian Developmental Biology (LEMDB), Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic
| | - Rebecca Collier
- Laboratory of Early Mammalian Developmental Biology (LEMDB), Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic
| | - David Potěšil
- Central European Institute of Technology, Masaryk University, 62500 Brno, Czech Republic
| | - Zbyněk Zdráhal
- Central European Institute of Technology, Masaryk University, 62500 Brno, Czech Republic
| | - Alexander W Bruce
- Laboratory of Early Mammalian Developmental Biology (LEMDB), Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 31, 37005 České Budějovice, Czech Republic
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3
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Anamthathmakula P, Winuthayanon W. Prostaglandin-Endoperoxide Synthase 2 (PTGS2) in the Oviduct: Roles in Fertilization and Early Embryo Development. Endocrinology 2021; 162:6128831. [PMID: 33539521 PMCID: PMC7901659 DOI: 10.1210/endocr/bqab025] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Indexed: 11/19/2022]
Abstract
The mammalian oviduct is a dynamic organ where important events such as final maturation of oocytes, transport of gametes, sperm capacitation, fertilization, embryo development, and transport take place. Prostaglandin-endoperoxide synthase 2 (PTGS2), also known as cyclooxygenase 2 (COX-2), is the rate-limiting enzyme in the production of prostaglandins (PGs) and plays an essential role during early pregnancy, including ovulation, fertilization, implantation, and decidualization. Even though the maternal-embryo communication originates in the oviduct, not many studies have systemically investigated PTGS2 signaling during early development. Most of the studies investigating implantation and decidualization processes in Ptgs2-/- mice employed embryo transfer into the uterus, thereby bypassing the mammalian oviduct. Consequently, an understanding of the mechanistic action as well as the regulation of PTGS2 and derived PGs in oviductal functions is far from complete. In this review, we aim to focus on the importance of PTGS2 and associated PGs signaling in the oviduct particularly in humans, farm animals, and laboratory rodents to provide a broad perspective to guide further research in this field. Specifically, we review the role of PTGS2-derived PGs in fertilization, embryo development, and transport. We focus on the actions of ovarian steroid hormones on PTGS2 regulation in the oviduct. Understanding of cellular PTGS2 function during early embryo development and transport in the oviduct will be an important step toward a better understanding of reproduction and may have potential implication in the assisted reproductive technology.
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Affiliation(s)
- Prashanth Anamthathmakula
- School of Molecular Biosciences, Center for Reproductive Biology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
- Correspondence: Wipawee Winuthayanon, PhD, BSN,Washington State University, Pullman, WA 99164, USA. E-mail: ; and Prashanth Anamthathmakula, PhD, Washington State University, Pullman, WA 99164, USA. E-mail:
| | - Wipawee Winuthayanon
- School of Molecular Biosciences, Center for Reproductive Biology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
- Correspondence: Wipawee Winuthayanon, PhD, BSN,Washington State University, Pullman, WA 99164, USA. E-mail: ; and Prashanth Anamthathmakula, PhD, Washington State University, Pullman, WA 99164, USA. E-mail:
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Harwalkar K, Ford MJ, Teng K, Yamanaka N, Yang B, Burtscher I, Lickert H, Yamanaka Y. Anatomical and cellular heterogeneity in the mouse oviduct-its potential roles in reproduction and preimplantation development†. Biol Reprod 2021; 104:1249-1261. [PMID: 33693543 DOI: 10.1093/biolre/ioab043] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/25/2020] [Accepted: 03/04/2021] [Indexed: 01/24/2023] Open
Abstract
The oviduct/fallopian tube is a tube-like structure that extends from the uterus to the ovary. It is an essential reproductive organ that provides an environment for internal fertilization and preimplantation development. However, our knowledge of its regional and cellular heterogeneity is still limited. Here, we examined the anatomical complexity of mouse oviducts using modern imaging techniques and fluorescence reporter lines. We found that there are consistent coiling patterns and turning points in the coiled mouse oviduct that serve as reliable landmarks for luminal morphological regionalities. We also found previously unrecognized anatomical structures in the isthmus and uterotubal junction, which likely play roles in reproduction. Furthermore, we demarcated the ampulla-isthmus junction as a distinct region. Taken together, the oviduct mucosal epithelium has highly diverse structures with distinct epithelial cell populations, reflecting its complex functions in reproduction.
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Affiliation(s)
- Keerthana Harwalkar
- Rosalind and Morris Goodman Cancer Research Centre, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Matthew J Ford
- Rosalind and Morris Goodman Cancer Research Centre, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Katie Teng
- Rosalind and Morris Goodman Cancer Research Centre, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Nobuko Yamanaka
- Rosalind and Morris Goodman Cancer Research Centre, Montreal, Quebec, Canada
| | - Brenna Yang
- Rosalind and Morris Goodman Cancer Research Centre, Montreal, Quebec, Canada
| | - Ingo Burtscher
- Institute of Diabetes and Regeneration Research, Helmholtz Diabetes Center, Helmholtz Center Munich, Munich, Germany
- Institute of Stem Cell Research, Helmholtz Center, Munich, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Diabetes Center, Helmholtz Center Munich, Munich, Germany
- Institute of Stem Cell Research, Helmholtz Center, Munich, Germany
- German Centre for Diabetes Research (DZD), Munich, Germany
- Department of Medicine, Technical University of Munich, Munich, Germany
| | - Yojiro Yamanaka
- Rosalind and Morris Goodman Cancer Research Centre, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
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van Marion ES, Speksnijder JP, Hoek J, Boellaard WPA, Dinkelman-Smit M, Chavli EA, Steegers-Theunissen RPM, Laven JSE, Baart EB. Time-lapse imaging of human embryos fertilized with testicular sperm reveals an impact on the first embryonic cell cycle. Biol Reprod 2021; 104:1218-1227. [PMID: 33690817 PMCID: PMC8181962 DOI: 10.1093/biolre/ioab031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/08/2021] [Accepted: 02/18/2021] [Indexed: 11/14/2022] Open
Abstract
Testicular sperm is increasingly used during in vitro fertilization treatment. Testicular sperm has the ability to fertilize the oocyte after intracytoplasmic sperm injection (ICSI), but they have not undergone maturation during epididymal transport. Testicular sperm differs from ejaculated sperm in terms of chromatin maturity, incidence of DNA damage, and RNA content. It is not fully understood what the biological impact is of using testicular sperm, on fertilization, preimplantation embryo development, and postimplantation development. Our goal was to investigate differences in human preimplantation embryo development after ICSI using testicular sperm (TESE-ICSI) and ejaculated sperm. We used time-lapse embryo culture to study these possible differences. Embryos (n = 639) originating from 208 couples undergoing TESE-ICSI treatment were studied and compared to embryos (n = 866) originating from 243 couples undergoing ICSI treatment with ejaculated sperm. Using statistical analysis with linear mixed models, we observed that pronuclei appeared 0.55 h earlier in TESE-ICSI embryos, after which the pronuclear stage lasted 0.55 h longer. Also, significantly more TESE-ICSI embryos showed direct unequal cleavage from the 1-cell stage to the 3-cell stage. TESE-ICSI embryos proceeded faster through the cleavage divisions to the 5- and the 6-cell stage, but this effect disappeared when we adjusted our model for maternal factors. In conclusion, sperm origin affects embryo development during the first embryonic cell cycle, but not developmental kinetics to the 8-cell stage. Our results provide insight into the biological differences between testicular and ejaculated sperm and their impact during human fertilization.
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Affiliation(s)
- E S van Marion
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - J P Speksnijder
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - J Hoek
- Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - W P A Boellaard
- Department of Urology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - M Dinkelman-Smit
- Department of Urology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - E A Chavli
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - R P M Steegers-Theunissen
- Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - J S E Laven
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - E B Baart
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.,Department of Developmental Biology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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Bolouki A, Zal F, Alaee S. Ameliorative effects of quercetin on the preimplantation embryos development in diabetic pregnant mice. J Obstet Gynaecol Res 2020; 46:736-744. [PMID: 32088935 DOI: 10.1111/jog.14219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/27/2020] [Accepted: 02/08/2020] [Indexed: 02/02/2023]
Abstract
AIM Maternal diabetes adversely retards the development of preimplantation embryos. Quercetin is a flavonoid belonging to phytoestrogens family and may be useful in treatment of reproductive disorders. The aim of this study was investigation of the ameliorative effects of quercetin administration on preimplantation embryo development in diabetic pregnancy. METHODS Diabetic and healthy female mice were treated with 30 mg/kg/day quercetin 4 weeks before conception. Blastocysts were recovered at the 4th day of pregnancy for protein and mRNA expression changes. Plasma sex-steroid levels were also analyzed. RESULTS Quercetin significantly decreased blood glucose levels in diabetic mice. Embryos retrieved from diabetic mice exhibited a considerable delay in morphological development. In diabetic mice with quercetin treatment, morphological distribution was shifted considerably to the well-developed stages. Serum estradiol level reduced in diabetic mice but, treatment with quercetin significantly increased serum estradiol level. While IGF1R, integrin αvβ3, and Cox2 mRNA expression in the blastocyst of diabetic mice decreased significantly, quercetin treatment caused increasing expression levels of these genes. Expression of the Caspase3 gene increased dramatically in the collected blastocysts from diabetic mice and reduced following quercetin treatment. Besides, the inactive β-catenin protein level in the blastocysts of diabetic mice was higher than that in normal mice, while treatment with quercetin decreased the level of inactive β-catenin protein in the blastocyst of diabetic mice. CONCLUSION Quercetin protects preimplantation embryos from destructive effects of diabetes. The amelioration of sex hormones disturbance in early pregnancy may help to treat reproductive disorders in diabetic women. Quercetin can be considered as a novel solution to the improvement of reproductive disorders in the diabetic females.
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Affiliation(s)
- Ayeh Bolouki
- Biochemistry Department, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Fatemeh Zal
- Biochemistry Department, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.,Infertility Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sanaz Alaee
- Reproductive Biology Department, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
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Martinez AM, Cheong A, Ying J, Xue J, Kannan K, Leung YK, Thomas MA, Ho SM. Effects of High-Butterfat Diet on Embryo Implantation in Female Rats Exposed to Bisphenol A. Biol Reprod 2015; 93:147. [PMID: 26510865 DOI: 10.1095/biolreprod.115.131433] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/22/2015] [Indexed: 12/21/2022] Open
Abstract
Bisphenol A (BPA) is an endocrine disruptor associated with poor pregnancy outcomes in human and rodents. The effects of butterfat diets on embryo implantation and whether it modifies BPA's actions are currently unknown. We aimed to determine the effects of butterfat diet on embryo implantation success in female rats exposed to an environmentally relevant dose of BPA. Female Sprague-Dawley rats were exposed to dietary butterfat (10% or 39% kcal/kg body weight [BW]) in the presence or absence of BPA (250 μg/kg BW) or ethinylestradiol (0.1 μg/kg BW) shortly before and during pregnancy to assess embryo implantation potentials by preimplantation development and transport, in vitro blastulation, outgrowth, and implantation. On gestational day (GD) 4.5, rats treated with BPA alone had higher serum total BPA level (2.3-3.7 ng/ml). They had more late-stage preimplantation embryos, whereas those receiving high butterfat (HBF) diet had the most advanced-stage embryos; dams cotreated with HBF and BPA had the most number of advanced embryos. BPA markedly delayed embryo transport to the uterus, but neither amount of butterfat had modifying effects. An in vitro implantation assay showed HBF doubled the outgrowth area, with BPA having no effect. In vivo, BPA reduced the number of implanted embryos on GD8, and cotreatment with HBF eliminated this adverse effect. HBF diet overall resulted in more and larger GD8 embryos. This study reveals the implantation disruptive effects of maternal exposure to an environmentally relevant dose of BPA and identifies HBF diet as a modifier of BPA in promoting early embryonic health.
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Affiliation(s)
- Alan M Martinez
- Division of Reproductive Endocrinology & Infertility, Department of Obstetrics & Gynecology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Ana Cheong
- Division of Environmental Genetics and Molecular Toxicology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Jun Ying
- Division of Biostatistics and Bioinformatics, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Jingchuan Xue
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Albany, New York
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Albany, New York Biochemistry Department, Faculty of Science and Experimental Biochemistry Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Yuet-Kin Leung
- Division of Environmental Genetics and Molecular Toxicology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio Cincinnati Cancer Center, Cincinnati, Ohio
| | - Michael A Thomas
- Division of Reproductive Endocrinology & Infertility, Department of Obstetrics & Gynecology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Shuk-Mei Ho
- Division of Environmental Genetics and Molecular Toxicology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio Cincinnati Cancer Center, Cincinnati, Ohio Cincinnati Veteran Affairs Hospital Medical Center, Cincinnati, Ohio
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Tarín JJ, García-Pérez MA, Hermenegildo C, Cano A. Changes in sex ratio from fertilization to birth in assisted-reproductive-treatment cycles. Reprod Biol Endocrinol 2014; 12:56. [PMID: 24957129 PMCID: PMC4079184 DOI: 10.1186/1477-7827-12-56] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/10/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Western gender-neutral countries, the sex ratio at birth is estimated to be approximately 1.06. This ratio is lower than the estimated sex ratio at fertilization which ranges from 1.07 to 1.70 depending on the figures of sex ratio at birth and differential embryo/fetal mortality rates taken into account to perform these estimations. Likewise, little is known about the sex ratio at implantation in natural and assisted-reproduction-treatment (ART) cycles. In this bioessay, we aim to estimate the sex ratio at fertilization and implantation using data from embryos generated by standard in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in preimplantation genetic diagnosis cycles. Thereafter, we compare sex ratios at implantation and birth in cleavage- and blastocyst-stage-transfer cycles to propose molecular mechanisms accounting for differences in post-implantation male and female mortality and thereby variations in sex ratios at birth in ART cycles. METHODS A literature review based on publications up to December 2013 identified by PubMed database searches. RESULTS Sex ratio at both fertilization and implantation is estimated to be between 1.29 and 1.50 in IVF cycles and 1.07 in ICSI cycles. Compared with the estimated sex ratio at implantation, sex ratio at birth is lower in IVF cycles (1.03 after cleavage-stage transfer and 1.25 after blastocyst-stage transfer) but similar and close to unity in ICSI cycles (0.95 after cleavage-stage transfer and 1.04 after blastocyst-stage transfer). CONCLUSIONS In-vitro-culture-induced precocious X-chromosome inactivation together with ICSI-induced decrease in number of trophectoderm cells in female blastocysts may account for preferential female mortality at early post-implantation stages and thereby variations in sex ratios at birth in ART cycles.
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Affiliation(s)
- Juan J Tarín
- Department of Functional Biology and Physical Anthropology, Faculty of Biological Sciences, University of Valencia, Burjassot, Valencia 46100, Spain
| | - Miguel A García-Pérez
- Department of Genetics, Faculty of Biological Sciences, University of Valencia, Burjassot, Valencia 46100; and Research Unit-INCLIVA, Hospital Clínico de Valencia, Valencia 46010, Spain
| | - Carlos Hermenegildo
- Department of Physiology, Faculty of Medicine, University of Valencia, Valencia 46010; and Research Unit-INCLIVA, Hospital Clínico de Valencia, Valencia 46010, Spain
| | - Antonio Cano
- Department of Pediatrics, Obstetrics and Gynecology, Faculty of Medicine, University of Valencia, Valencia 46010; and Service of Obstetrics and Gynecology, University Hospital Dr. Peset, Valencia 46017, Spain
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