1
|
Sun Y, Shen Q, Xi H, Sui L, Fu Y, Zhao J. Comparison of pregnancy outcomes between 4th day morula and 5th day blastocyst after embryo transfer: a retrospective cohort study. BMC Pregnancy Childbirth 2024; 24:458. [PMID: 38961359 PMCID: PMC11223283 DOI: 10.1186/s12884-024-06597-7] [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: 12/19/2023] [Accepted: 05/20/2024] [Indexed: 07/05/2024] Open
Abstract
BACKGROUND This study was designed to evaluate pregnancy outcomes between morulae transferred on day 4 (D4) and blastocysts transferred on day 5 (D5). METHODS From September 2017 to September 2020, 1963 fresh transfer cycles underwent early follicular phase extra-long protocol for assisted conception in our fertility center were divided into D4 (324 cases) and D5 (1639 cases) groups, and the general situation and other differences of patients in both groups were compared. To compare the differences in pregnancy outcomes, the D4 and D5 groups were further divided into groups A and B based on single and double embryo transfers. Furthermore, the cohort was divided into two groups: those with live births (1116 cases) and those without (847 cases), enabling a deeper evaluation of the effects of D4 or D5 transplantation on assisted reproductive outcomes. RESULTS In single embryo transfer, there was no significant difference between groups D4A and D5A (P > 0.05). In double embryo transfer, group D4B had a lower newborn birthweight and a larger proportion of low birthweight infants (P < 0.05). The preterm delivery rate, twin delivery rate, cesarean delivery rate, and percentage of low birthweight infants were lower in the D5A group than in the D5B group (P < 0.05). Analysis of factors influencing live birth outcomes further confirmed the absence of a significant difference between D4 and D5 transplantation in achieving live birth (P > 0.05). CONCLUSION When factors such as working life and hospital holidays are being considered, D4 morula transfer may be a good alternative to D5 blastocyst transfer. Given the in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) success rate and risk of twin pregnancy, D4 morula transfer requires an adapted decision between single and double embryo transfer, although a single blastocyst transfer is recommended for the D5 transfer in order to decrease the twin pregnancy rate. In addition, age, endometrial thickness and other factors need to be taken into account to personalize the IVF program and optimize pregnancy outcomes.
Collapse
Affiliation(s)
- Yiqun Sun
- Department of Obstetrics and Gynecology, Reproduction Center, the Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Qi Shen
- Department of Obstetrics and Gynecology, Reproduction Center, the Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Haitao Xi
- Department of Obstetrics and Gynecology, Reproduction Center, the Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Liucai Sui
- Department of Obstetrics and Gynecology, Reproduction Center, the Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Yanghua Fu
- Department of Obstetrics and Gynecology, Reproduction Center, the Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Junzhao Zhao
- Department of Obstetrics and Gynecology, Reproduction Center, the Second Affiliated Hospital and Yuying, Children's Hospital of Wenzhou Medical University, Wenzhou, 325000, China.
| |
Collapse
|
2
|
Kandouz M. Cell Death, by Any Other Name…. Cells 2024; 13:325. [PMID: 38391938 PMCID: PMC10886887 DOI: 10.3390/cells13040325] [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: 12/31/2023] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
Studies trying to understand cell death, this ultimate biological process, can be traced back to a century ago. Yet, unlike many other fashionable research interests, research on cell death is more alive than ever. New modes of cell death are discovered in specific contexts, as are new molecular pathways. But what is "cell death", really? This question has not found a definitive answer yet. Nevertheless, part of the answer is irreversibility, whereby cells can no longer recover from stress or injury. Here, we identify the most distinctive features of different modes of cell death, focusing on the executive final stages. In addition to the final stages, these modes can differ in their triggering stimulus, thus referring to the initial stages. Within this framework, we use a few illustrative examples to examine how intercellular communication factors in the demise of cells. First, we discuss the interplay between cell-cell communication and cell death during a few steps in the early development of multicellular organisms. Next, we will discuss this interplay in a fully developed and functional tissue, the gut, which is among the most rapidly renewing tissues in the body and, therefore, makes extensive use of cell death. Furthermore, we will discuss how the balance between cell death and communication is modified during a pathological condition, i.e., colon tumorigenesis, and how it could shed light on resistance to cancer therapy. Finally, we briefly review data on the role of cell-cell communication modes in the propagation of cell death signals and how this has been considered as a potential therapeutic approach. Far from vainly trying to provide a comprehensive review, we launch an invitation to ponder over the significance of cell death diversity and how it provides multiple opportunities for the contribution of various modes of intercellular communication.
Collapse
Affiliation(s)
- Mustapha Kandouz
- Department of Pathology, School of Medicine, Wayne State University, 540 East Canfield Avenue, Detroit, MI 48201, USA;
- Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201, USA
| |
Collapse
|
3
|
McCoy RC, Summers MC, McCollin A, Ottolini CS, Ahuja K, Handyside AH. Meiotic and mitotic aneuploidies drive arrest of in vitro fertilized human preimplantation embryos. Genome Med 2023; 15:77. [PMID: 37779206 PMCID: PMC10544495 DOI: 10.1186/s13073-023-01231-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 09/12/2023] [Indexed: 10/03/2023] Open
Abstract
BACKGROUND The high incidence of aneuploidy in early human development, arising either from errors in meiosis or postzygotic mitosis, is the primary cause of pregnancy loss, miscarriage, and stillbirth following natural conception as well as in vitro fertilization (IVF). Preimplantation genetic testing for aneuploidy (PGT-A) has confirmed the prevalence of meiotic and mitotic aneuploidies among blastocyst-stage IVF embryos that are candidates for transfer. However, only about half of normally fertilized embryos develop to the blastocyst stage in vitro, while the others arrest at cleavage to late morula or early blastocyst stages. METHODS To achieve a more complete view of the impacts of aneuploidy, we applied low-coverage sequencing-based PGT-A to a large series (n = 909) of arrested embryos and trophectoderm biopsies. We then correlated observed aneuploidies with abnormalities of the first two cleavage divisions using time-lapse imaging (n = 843). RESULTS The combined incidence of meiotic and mitotic aneuploidies was strongly associated with blastocyst morphological grading, with the proportion ranging from 20 to 90% for the highest to lowest grades, respectively. In contrast, the incidence of aneuploidy among arrested embryos was exceptionally high (94%), dominated by mitotic aneuploidies affecting multiple chromosomes. In turn, these mitotic aneuploidies were strongly associated with abnormal cleavage divisions, such that 51% of abnormally dividing embryos possessed mitotic aneuploidies compared to only 23% of normally dividing embryos. CONCLUSIONS We conclude that the combination of meiotic and mitotic aneuploidies drives arrest of human embryos in vitro, as development increasingly relies on embryonic gene expression at the blastocyst stage.
Collapse
Affiliation(s)
- Rajiv C McCoy
- Department of Biology, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21212, USA.
| | - Michael C Summers
- London Women's Clinic, 113-115 Harley Street, Marylebone, London, W1G 6AP, UK
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, Kent, UK
- Present Address: London Women's Clinic, The Chesterfield, Nuffield Health Clinic, 3 Clifton Hill, Bristol, BS8 1BN, UK
| | - Abeo McCollin
- London Women's Clinic, 113-115 Harley Street, Marylebone, London, W1G 6AP, UK
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, Kent, UK
| | - Christian S Ottolini
- London Women's Clinic, 113-115 Harley Street, Marylebone, London, W1G 6AP, UK
- Department of Maternal and Fetal Medicine, University College London, 86-96 Chenies Mews, London, WC1E 6HX, UK
- Present Address: Juno Genetics Italia, Via Di Quarto Peperino 22, 00188, Rome, Italy
| | - Kamal Ahuja
- London Women's Clinic, 113-115 Harley Street, Marylebone, London, W1G 6AP, UK
| | - Alan H Handyside
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, Kent, UK
| |
Collapse
|
4
|
Matot R, Kalma Y, Rahav R, Azem F, Amir H, Ben-Yosef D. Cleavage stage at compaction-a good predictor for IVF outcome. Int J Gynaecol Obstet 2022; 161:997-1003. [PMID: 36495286 DOI: 10.1002/ijgo.14619] [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: 09/01/2022] [Revised: 11/15/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To analyze whether cleavage stage at compaction, and not only kinetics, can serve as a reliable predictor for clinical outcome. METHODS A retrospective cohort study including 1194 embryos, classified by compaction initiation stage (Group 1: compaction at fewer than eight cells, Group 2: compaction at eight cells, Group 3: compaction at more than eight cells). Of these, 815 embryos were evaluated for morphokinetic preimplantation parameters, and 379 embryos were analyzed for clinical implantation following thawing and transfer of single blastocysts during the same period. RESULTS In total, 1194 embryos were analyzed. Embryos that underwent compaction from more than eight cells (Group 3) exhibited more synchronous cleavage compared with Groups 1 and 2 (at both S2 and S3; P < 0.001), and displayed a significantly lower fragmentation rate. The likelihood of obtaining top-quality blastocysts decreased by 73% and 44% when comparing Group 3 embryos with those of Groups 1 and 2, respectively, (P < 0.03). Clinical validation of the results shows that while compaction from fewer than eight cells barely produced blastocysts for transfer, compaction at eight or more cells is crucial for implantation and birth (birth rates 11.1% and 18.5% for Groups 2 and 3, respectively). CONCLUSION Cleavage stage at compaction has a direct effect on blastocyst quality and subsequent pregnancy, so can be included in newly developed deep learning models for embryo selection.
Collapse
Affiliation(s)
- Ran Matot
- Fertility and IVF Institute, Tel-Aviv Sourasky Medical Center, Affiliated to Tel Aviv University, Tel Aviv, Israel
| | - Yael Kalma
- Fertility and IVF Institute, Tel-Aviv Sourasky Medical Center, Affiliated to Tel Aviv University, Tel Aviv, Israel
| | - Roni Rahav
- Fertility and IVF Institute, Tel-Aviv Sourasky Medical Center, Affiliated to Tel Aviv University, Tel Aviv, Israel
| | - Foad Azem
- Fertility and IVF Institute, Tel-Aviv Sourasky Medical Center, Affiliated to Tel Aviv University, Tel Aviv, Israel
| | - Hadar Amir
- Fertility and IVF Institute, Tel-Aviv Sourasky Medical Center, Affiliated to Tel Aviv University, Tel Aviv, Israel
| | - Dalit Ben-Yosef
- Fertility and IVF Institute, Tel-Aviv Sourasky Medical Center, Affiliated to Tel Aviv University, Tel Aviv, Israel.,Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| |
Collapse
|
5
|
Tan TCY, Dunning KR. Non-invasive assessment of oocyte developmental competence. Reprod Fertil Dev 2022; 35:39-50. [PMID: 36592982 DOI: 10.1071/rd22217] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Oocyte quality is a key factor influencing IVF success. The oocyte and surrounding cumulus cells, known collectively as the cumulus oocyte complex (COC), communicate bi-directionally and regulate each other's metabolic function to support oocyte growth and maturation. Many studies have attempted to associate metabolic markers with oocyte quality, including metabolites in follicular fluid or 'spent medium' following maturation, gene expression of cumulus cells and measuring oxygen consumption in medium surrounding COCs. However, these methods fail to provide spatial metabolic information on the separate oocyte and cumulus cell compartments. Optical imaging of the autofluorescent cofactors - reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] and flavin adenine dinucleotide (FAD) - has been put forward as an approach to generate spatially resolved measurements of metabolism within individual cells of the COC. The optical redox ratio (FAD/[NAD(P)H+FAD]), calculated from these cofactors, can act as an indicator of overall metabolic activity in the oocyte and cumulus cell compartments. Confocal microscopy, fluorescence lifetime imaging microscopy (FLIM) and hyperspectral microscopy may be used for this purpose. This review provides an overview of current optical imaging techniques that capture the inner biochemistry within cells of the COC and discusses the potential for such imaging to assess oocyte developmental competence.
Collapse
Affiliation(s)
- Tiffany C Y Tan
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia
| | - Kylie R Dunning
- Robinson Research Institute, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia
| |
Collapse
|
6
|
Lechniak D, Sell-Kubiak E, Warzych E. The metabolic profile of bovine blastocysts is affected by in vitro culture system and the pattern of first zygotic cleavage. Theriogenology 2022; 188:43-51. [DOI: 10.1016/j.theriogenology.2022.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 11/27/2022]
|
7
|
Leese HJ, McKeegan PJ, Sturmey RG. Amino Acids and the Early Mammalian Embryo: Origin, Fate, Function and Life-Long Legacy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:9874. [PMID: 34574797 PMCID: PMC8467587 DOI: 10.3390/ijerph18189874] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/27/2021] [Accepted: 08/27/2021] [Indexed: 12/11/2022]
Abstract
Amino acids are now recognised as having multiple cellular functions in addition to their traditional role as constituents of proteins. This is well-illustrated in the early mammalian embryo where amino acids are now known to be involved in intermediary metabolism, as energy substrates, in signal transduction, osmoregulation and as intermediaries in numerous pathways which involve nitrogen metabolism, e.g., the biosynthesis of purines, pyrimidines, creatine and glutathione. The amino acid derivative S-adenosylmethionine has emerged as a universal methylating agent with a fundamental role in epigenetic regulation. Amino acids are now added routinely to preimplantation embryo culture media. This review examines the routes by which amino acids are supplied to the early embryo, focusing on the role of the oviduct epithelium, followed by an outline of their general fate and function within the embryo. Functions specific to individual amino acids are then considered. The importance of amino acids during the preimplantation period for maternal health and that of the conceptus long term, which has come from the developmental origins of health and disease concept of David Barker, is discussed and the review concludes by considering the potential utility of amino acid profiles as diagnostic of embryo health.
Collapse
Affiliation(s)
- Henry J. Leese
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull HU6 7RX, UK;
| | - Paul J. McKeegan
- Centre for Anatomical and Human Sciences, Hull York Medical School, University of Hull, Hull HU6 7RX, UK;
| | - Roger G. Sturmey
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull HU6 7RX, UK;
- Division of Developmental Biology and Medicine, The University of Manchester, St Mary’s Hospital, Manchester M13 9WL, UK
| |
Collapse
|
8
|
Albertini DF. Embryo culture goes back to the future. J Assist Reprod Genet 2021; 37:1767-1768. [PMID: 32785875 DOI: 10.1007/s10815-020-01923-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
9
|
Aljahdali A, Airina RKRI, Velazquez MA, Sheth B, Wallen K, Osmond C, Watkins AJ, Eckert JJ, Smyth NR, Fleming TP. The duration of embryo culture after mouse IVF differentially affects cardiovascular and metabolic health in male offspring. Hum Reprod 2021; 35:2497-2514. [PMID: 33020802 PMCID: PMC7603862 DOI: 10.1093/humrep/deaa205] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/14/2020] [Indexed: 12/26/2022] Open
Abstract
STUDY QUESTION Do the long-term health outcomes following IVF differ depending upon the duration of embryo culture before transfer? SUMMARY ANSWER Using a mouse model, we demonstrate that in male but not female offspring, adverse cardiovascular (CV) health was more likely with prolonged culture to the blastocyst stage, but metabolic dysfunction was more likely if embryo transfer (ET) occurred at the early cleavage stage. WHAT IS KNOWN ALREADY ART associate with increased risk of adverse CV and metabolic health in offspring, and these findings have been confirmed in animal models in the absence of parental infertility issues. It is unclear which specific ART treatments may cause these risks. There is increasing use of blastocyst, versus cleavage-stage, transfer in clinical ART which does not appear to impair perinatal health of children born, but the longer-term health implications are unknown. STUDY DESIGN, SIZE, DURATION Five mouse groups were generated comprising: (i) natural mating (NM)—naturally mated, non-superovulated and undisturbed gestation; (ii) IV-ET-2Cell—in-vivo derived two-cell embryos collected from superovulated mothers, with immediate ET to recipients; (iii) IVF-ET-2Cell—IVF generated embryos, from oocytes from superovulated mothers, cultured to the two-cell stage before ET to recipients; (iv) IV-ET-BL—in-vivo derived blastocysts collected from superovulated mothers, with immediate ET to recipients; (v) IVF-ET-BL—IVF generated embryos, from oocytes from superovulated mothers, cultured to the blastocyst stage before ET to recipients. Both male and female offspring were analysed for growth, CV and metabolic markers of health. There were 8–13 litters generated for each group for analyses; postnatal data were analysed by multilevel random effects regression to take account of between-mother and within-mother variation and litter size. PARTICIPANTS/MATERIALS, SETTINGS, METHODS C57/BL6 female mice (3–4 weeks old) were used for oocyte production; CBA males for sperm with human tubal fluid medium were used for IVF. Embryos were transferred (ET) to MF1 pseudo-pregnant recipients at the two-cell stage or cultured in synthetic oviductal medium enriched with potassium medium to the blastocyst stage before ET. Control in-vivo embryos from C57BL6 × CBA matings were collected and immediately transferred at the two-cell or blastocyst stage. Postnatal assays included growth rate up to 27 weeks; systolic blood pressure (SBP) at 9, 15 and 21 weeks; lung and serum angiotensin-converting enzyme (ACE) activity at time of cull (27 weeks); glucose tolerance test (GTT; 27 weeks); basal glucose and insulin levels (27 weeks); and lipid accumulation in liver cryosections using Oil Red O imaging (27 weeks). MAIN RESULTS AND THE ROLE OF CHANCE Blastocysts formed by IVF developed at a slower rate and comprised fewer cells that in-vivo generated blastocysts without culture (P < 0.05). Postnatal growth rate was increased in all four experimental treatments compared with NM group (P < 0.05). SBP, serum and lung ACE and heart/body weight were higher in IVF-ET-BL versus IVF-ET-2Cell males (P < 0.05) and higher than in other treatment groups, with SBP and lung ACE positively correlated (P < 0.05). Glucose handling (GTT AUC) was poorer and basal insulin levels were higher in IVF-ET-2Cell males than in IVF-ET-BL (P < 0.05) with the glucose:insulin ratio more negatively correlated with body weight in IVF-ET-2Cell males than in other groups. Liver/body weight and liver lipid droplet diameter and density in IVF-ET-2Cell males were higher than in IVF-ET-BL males (P < 0.05). IVF groups had poorer health characteristics than their in-vivo control groups, indicating that outcomes were not caused specifically by background techniques (superovulation, ET). No consistent health effects from duration of culture were identified in female offspring. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION Results from experimental animal models cannot be extrapolated to humans. Nevertheless, they are valuable to develop conceptual models, in this case, in the absence of confounding parental infertility, in assessing the safety of ART manipulations. WIDER IMPLICATIONS OF THE FINDINGS The study indicates that longer duration of embryo culture after IVF up to blastocyst before ET leads to increased dysfunction of CV health in males compared with IVF and shorter cleavage-stage ET. However, the metabolic health of male offspring was poorer after shorter versus longer culture duration. This distinction indicates that the origin of CV and metabolic health phenotypes after ART may be different. The poorer metabolic health of males after cleavage-stage ET coincides with embryonic genome activation occurring at the time of ET. STUDY FUNDING/COMPETING INTEREST(S) This work was supported through the European Union FP7-CP-FP Epihealth programme (278418) and FP7-PEOPLE-2012-ITN EpiHealthNet programme (317146) to T.P.F., the Biotechnology and Biological Sciences Research Council (BBSRC) (BB/F007450/1) to T.P.F., and the Saudi government, University of Jeddah and King Abdulaziz University to A.A. The authors have no conflicts of interest to declare.
Collapse
Affiliation(s)
- Anan Aljahdali
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK.,University of Jeddah, Jeddah, Saudi Arabia
| | - R K Raja Ili Airina
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Miguel A Velazquez
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK
| | - Bhavwanti Sheth
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Katrina Wallen
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Clive Osmond
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton SO16 6YD, UK
| | - Adam J Watkins
- Division of Child Health, Obstetrics and Gynaecology, Faculty of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
| | - Judith J Eckert
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Neil R Smyth
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Tom P Fleming
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
| |
Collapse
|
10
|
Huang TTF, Kosasa T, Walker B, Arnett C, Huang CTF, Yin C, Harun Y, Ahn HJ, Ohta A. Deep learning neural network analysis of human blastocyst expansion from time-lapse image files. Reprod Biomed Online 2021; 42:1075-1085. [PMID: 33820741 DOI: 10.1016/j.rbmo.2021.02.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/23/2021] [Accepted: 02/27/2021] [Indexed: 12/17/2022]
Abstract
RESEARCH QUESTION Can artificial intelligence (AI) discriminate a blastocyst's cellular area from unedited time-lapse image files using semantic segmentation and a deep learning optimized U-Net architecture for use in selecting single blastocysts for transfer? DESIGN This platform was retrospectively applied to time-lapse files from 101 sequentially transferred single blastocysts that were prospectively selected for transfer by their highest expansion ranking within cohorts using a 10 h expansion assay rather than standard grading. RESULTS The AI platform provides expansion curves and raw data files to classify and compare blastocyst phenotypes within both cohorts and populations. Of 35 sequential unbiopsied single blastocyst transfers, 23 (65.7%) resulted in a live birth. Of 66 sequential single euploid blastocyst transfers, also selected for their most robust expansion, 49 (74.2%) resulted in live birth. The AI platform revealed that the averaged expansion rate was significantly (P = 0.007) greater in euploid blastocysts that resulted in live births compared with those resulting in failure to give a live birth. The platform further provides a framework to analyse fragmentation phenotypes that can test new hypotheses for developmental regulation during the preimplantation period. CONCLUSIONS AI can be used to quantitatively describe blastocyst expansion from unedited time-lapse image files and can be used to quantitatively rank-order blastocysts for transfer. Early clinical results from such single blastocyst selection suggests that live birth rates without biopsy may be comparable to those found using single euploid blastocysts in younger, good responder patients.
Collapse
Affiliation(s)
- Thomas T F Huang
- Pacific In Vitro Fertilization Institute and John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
| | - Thomas Kosasa
- Pacific In Vitro Fertilization Institute and John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Brienne Walker
- Pacific In Vitro Fertilization Institute and John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Christina Arnett
- Advanced Reproductive Center of Hawaii, Kapiolani Medical Center for Women and Children's Health, Honolulu, Hawaii, USA
| | - Christopher T F Huang
- Advanced Reproductive Center of Hawaii, Kapiolani Medical Center for Women and Children's Health, Honolulu, Hawaii, USA
| | - Chelsea Yin
- Pacific In Vitro Fertilization Institute and John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Yousuf Harun
- Department of Electrical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Hyeong J Ahn
- Department of Quantitative Health Sciences, University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii, USA
| | - Aaron Ohta
- Department of Electrical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| |
Collapse
|
11
|
Altundag Ö, Çelebi-Saltik B. From Embryo to Adult: One Carbon Metabolism in Stem Cells. Curr Stem Cell Res Ther 2021; 16:175-188. [PMID: 32652922 DOI: 10.2174/1574888x15666200712191308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/16/2020] [Accepted: 04/23/2020] [Indexed: 11/22/2022]
Abstract
Stem cells are undifferentiated cells with self-renewal property and varying differentiation potential that allow the regeneration of tissue cells of an organism throughout adult life beginning from embryonic development. Through the asymmetric cell divisions, each stem cell replicates itself and produces an offspring identical with the mother cell, and a daughter cell that possesses the characteristics of a progenitor cell and commits to a specific lineage to differentiate into tissue cells to maintain homeostasis. To maintain a pool of stem cells to ensure tissue regeneration and homeostasis, it is important to regulate the metabolic functioning of stem cells, progenitor cells and adult tissue stem cells that will meet their internal and external needs. Upon fertilization, the zygote transforms metabolic reprogramming while implantation, embryonic development, organogenesis processes and after birth through adult life. Metabolism in stem cells is a concept that is relatively new to be enlightened. There are no adequate and comprehensive in vitro studies on the comparative analysis of the effects of one-carbon (1-C) metabolism on fetal and adult stem cells compared to embryonic and cancer stem cells' studies that have been reported recently. Since 1-C metabolism is linking parental environmental/ dietary factors and fetal development, investigating the epigenetic, genetic, metabolic and developmental effects on adult period is necessary. Several mutations and abnormalities in 1-C metabolism have been noted in disease changing from diabetes, cancer, pregnancy-related outcomes such as pre-eclampsia, spontaneous abortion, placental abruption, premature delivery, and cardiovascular diseases. In this review, the effects of 1-C metabolism, mainly the methionine and folate metabolism, in stem cells that exist in different developmental stages will be discussed.
Collapse
Affiliation(s)
- Özlem Altundag
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Sihhiye, Ankara, Turkey
| | - Betül Çelebi-Saltik
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Sihhiye, Ankara, Turkey
| |
Collapse
|
12
|
Coticchio G, Lagalla C, Sturmey R, Pennetta F, Borini A. The enigmatic morula: mechanisms of development, cell fate determination, self-correction and implications for ART. Hum Reprod Update 2020; 25:422-438. [PMID: 30855681 DOI: 10.1093/humupd/dmz008] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 01/20/2019] [Accepted: 02/11/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Assisted reproduction technology offers the opportunity to observe the very early stages of human development. However, due to practical constraints, for decades morphological examination of embryo development has been undertaken at a few isolated time points at the stages of fertilisation (Day 1), cleavage (Day 2-3) and blastocyst (Day 5-6). Rather surprisingly, the morula stage (Day 3-4) has been so far neglected, despite its involvement in crucial cellular processes and developmental decisions. OBJECTIVE AND RATIONALE The objective of this review is to collate novel and unsuspected insights into developmental processes occurring during formation of the morula, highlighting the key importance of this stage for a better understanding of preimplantation development and an improvement of ART. SEARCH METHODS PubMed was used to search the MEDLINE database for peer-reviewed English-language original articles and reviews concerning the morula stage in mammals. Searches were performed by adopting 'embryo', 'morula', 'compaction', 'cell fate' and 'IVF/assisted reproduction' as main terms, in association with other keywords expressing concepts relevant to the subject (e.g. cell polarity). The most relevant publications, i.e. those concerning major phenomena occurring during formation of the morula in established experimental models and the human species, were assessed and discussed critically. OUTCOMES Novel live cell imaging technologies and cell biology studies have extended our understanding of morula formation as a key stage for the development of the blastocyst and determination of the inner cell mass (ICM) and the trophectoderm (TE). Cellular processes, such as dynamic formation of filopodia and cytoskeleton-mediated zippering cell-to-cell interactions, intervene to allow cell compaction (a geometrical requisite essential for development) and formation of the blastocoel, respectively. At the same time, differential orientation of cleavage planes, cell polarity and cortical tensile forces interact and cooperate to position blastomeres either internally or externally, thereby influencing their cellular fate. Recent time lapse microscopy (TLM) observations also suggest that in the human the process of compaction may represent an important checkpoint for embryo viability, through which chromosomally abnormal blastomeres are sensed and eliminated by the embryo. WIDER IMPLICATIONS In clinical embryology, the morula stage has been always perceived as a 'black box' in the continuum of preimplantation development. This has dictated its virtual exclusion from mainstream ART procedures. Recent findings described in this review indicate that the morula, and the associated process of compaction, as a crucial stage not only for the formation of the blastocyst, but also for the health of the conceptus. This understanding may open new avenues for innovative approaches to embryo manipulation, assessment and treatment.
Collapse
Affiliation(s)
| | - Cristina Lagalla
- 9.Baby, Family and Fertility Center, Via Dante 15, Bologna, Italy
| | - Roger Sturmey
- Centre for Cardiovascular Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
| | | | - Andrea Borini
- 9.Baby, Family and Fertility Center, Via Dante 15, Bologna, Italy
| |
Collapse
|
13
|
Simopoulou M, Sfakianoudis K, Tsioulou P, Rapani A, Maziotis E, Giannelou P, Grigoriadis S, Pantou A, Nikolettos K, Vlahos N, Pantos K, Koutsilieris M. Should the flexibility enabled by performing a day-4 embryo transfer remain as a valid option in the IVF laboratory? A systematic review and network meta-analysis. J Assist Reprod Genet 2019; 36:1049-1061. [PMID: 31111304 PMCID: PMC6603118 DOI: 10.1007/s10815-019-01475-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/02/2019] [Indexed: 02/08/2023] Open
Abstract
PURPOSE The present systematic review and network meta-analysis aims to uniquely bring to literature data supporting the true place of the alternative practice of day-4 embryo transfer (D4 ET) in an IVF laboratory, beyond the one-dimensional option of facilitating a highly demanding program. METHODS A systematic search was conducted in the databases of PubMed/Medline, Embase, and Cochrane Central Library, resulting to six prospective along with nine retrospective cohort studies meeting eligibility criteria for inclusion. A comparison of D4 ET with day-2 (D2), day-3 (D3), and day-5 (D5) ET, respectively, was performed employing R statistics. RESULTS The sourced results indicate no statistically significant difference regarding clinical pregnancy rates, and ongoing pregnancy/live birth rates stemming from the comparison of D4 with D2, D4 with D3, and D4 with D5 ET, respectively. Additionally, no statistically significant difference could be established in respect to cancelation, and miscarriage rates, following the comparison of D4 with D3 and D4 with D5 ET. Interestingly, we report statistically significant lower preterm birth rates associated with D4 ET, in contrast with D5 ET (RR, 0.19; 95% CI, 0.05-0.67; p value = 0.01). CONCLUSIONS The aforementioned results may serve as advocates buttressing the option of D4 ET as a valid candidate in the ET decision-making process. Possible limitations of the current study are the publication bias stemming from the retrospective nature of certain included studies, along with various deviations among studies' design, referring to number and quality of transferred embryos, or different culture conditions referring to studies of previous decades.
Collapse
Affiliation(s)
- M Simopoulou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias, 11527, Athens, Greece.
- Assisted Conception Unit, 2nd Department of Obstetrics and Gynecology, Aretaieion Hospital, Medical School, National and Kapodistrian University of Athens, 76, Vasilisis Sofias Avenue, 11528, Athens, Greece.
| | - K Sfakianoudis
- Centre for Human Reproduction, Genesis Athens Clinic, 14-16, Papanikoli, 15232, Athens, Greece
| | - P Tsioulou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias, 11527, Athens, Greece
| | - A Rapani
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias, 11527, Athens, Greece
| | - E Maziotis
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias, 11527, Athens, Greece
| | - P Giannelou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias, 11527, Athens, Greece
| | - S Grigoriadis
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias, 11527, Athens, Greece
| | - A Pantou
- Centre for Human Reproduction, Genesis Athens Clinic, 14-16, Papanikoli, 15232, Athens, Greece
| | - K Nikolettos
- Assisted Reproduction Unit of Thrace "Embryokosmogenesis", Apalos, 68132, Alexandroupoli, Greece
| | - N Vlahos
- Assisted Conception Unit, 2nd Department of Obstetrics and Gynecology, Aretaieion Hospital, Medical School, National and Kapodistrian University of Athens, 76, Vasilisis Sofias Avenue, 11528, Athens, Greece
| | - K Pantos
- Centre for Human Reproduction, Genesis Athens Clinic, 14-16, Papanikoli, 15232, Athens, Greece
| | - M Koutsilieris
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, 75, Mikras Asias, 11527, Athens, Greece
| |
Collapse
|
14
|
Smith HL, Stevens A, Minogue B, Sneddon S, Shaw L, Wood L, Adeniyi T, Xiao H, Lio P, Kimber SJ, Brison DR. Systems based analysis of human embryos and gene networks involved in cell lineage allocation. BMC Genomics 2019; 20:171. [PMID: 30836937 PMCID: PMC6399968 DOI: 10.1186/s12864-019-5558-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 02/22/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Little is understood of the molecular mechanisms involved in the earliest cell fate decision in human development, leading to the establishment of the trophectoderm (TE) and inner cell mass (ICM) stem cell population. Notably, there is a lack of understanding of how transcriptional networks arise during reorganisation of the embryonic genome post-fertilisation. RESULTS We identified a hierarchical structure of preimplantation gene network modules around the time of embryonic genome activation (EGA). Using network models along with eukaryotic initiation factor (EIF) and epigenetic-associated gene expression we defined two sets of blastomeres that exhibited diverging tendencies towards ICM or TE. Analysis of the developmental networks demonstrated stage specific EIF expression and revealed that histone modifications may be an important epigenetic regulatory mechanism in preimplantation human embryos. Comparison to published RNAseq data confirmed that during EGA the individual 8-cell blastomeres are transcriptionally primed for the first lineage decision in development towards ICM or TE. CONCLUSIONS Using multiple systems biology approaches to compare developmental stages in the early human embryo with single cell transcript data from blastomeres, we have shown that blastomeres considered to be totipotent are not transcriptionally equivalent. Furthermore we have linked the developmental interactome to individual blastomeres and to later cell lineage. This has clinical implications for understanding the impact of fertility treatments and developmental programming of long term health.
Collapse
Affiliation(s)
- H. L. Smith
- Maternal and Fetal Health Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| | - A. Stevens
- Division of Developmental Biology & Medicine, School of Medical Sciences, University of Manchester, Manchester Academic Health Sciences Centre, 5th Floor Research, Royal Manchester Children’s Hospital, Oxford Road, Manchester, M13 9WL UK
| | - B. Minogue
- Maternal and Fetal Health Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| | - S. Sneddon
- Maternal and Fetal Health Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| | - L. Shaw
- Maternal and Fetal Health Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| | - L. Wood
- Department of Reproductive Medicine, Saint Mary’s Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| | - T. Adeniyi
- Department of Reproductive Medicine, Saint Mary’s Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| | - H. Xiao
- Computer Laboratory, William Gates Building, University of Cambridge, Cambridge, UK
| | - P. Lio
- Computer Laboratory, William Gates Building, University of Cambridge, Cambridge, UK
| | - S. J. Kimber
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| | - D. R. Brison
- Maternal and Fetal Health Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
- Department of Reproductive Medicine, Saint Mary’s Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Sciences Centre, Oxford Road, Manchester, M13 9WL UK
| |
Collapse
|
15
|
Duranthon V, Chavatte-Palmer P. Long term effects of ART: What do animals tell us? Mol Reprod Dev 2018; 85:348-368. [DOI: 10.1002/mrd.22970] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/09/2018] [Indexed: 01/01/2023]
|
16
|
Leese HJ, Guerif F, Allgar V, Brison DR, Lundin K, Sturmey RG. Biological optimization, the Goldilocks principle, and how much is lagom in the preimplantation embryo. Mol Reprod Dev 2018; 83:748-754. [PMID: 27465801 DOI: 10.1002/mrd.22684] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/18/2016] [Indexed: 11/09/2022]
Abstract
The quiet embryo hypothesis postulates that early embryo viability is associated with a relatively low metabolism (Leese, 2002 BioEssays 24: 845-849). This proposal is re-visited here using retrospective and prospective data on the metabolic activity and kinetics of preimplantation development alongside the concept that an optimal range of such indices and of energetic efficiency influences embryogenesis. It is concluded that these considerations may be rationalized by proposing the existence of a "Goldilocks zone," or as it is known in Sweden, of lagom-meaning "just the right amount"-within which embryos with maximum developmental potential can be categorized. Mol. Reprod. Dev. 83: 748-754, 2016 © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Henry J Leese
- Centre for Cardiovascular Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom.
| | - Fabrice Guerif
- Medecine et Biologie de la Reproduction, Université de Tours, Tours, France
| | - Victoria Allgar
- Centre for Cardiovascular Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Daniel R Brison
- Department of Reproductive Medicine, Central Manchester University Hospitals NHS Foundation Trust, St Mary's Hospital, Manchester, United Kingdom
| | - Kersti Lundin
- Reproductive Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Roger G Sturmey
- Centre for Cardiovascular Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom
| |
Collapse
|
17
|
Sutton-McDowall ML, Gosnell M, Anwer AG, White M, Purdey M, Abell AD, Goldys EM, Thompson JG. Hyperspectral microscopy can detect metabolic heterogeneity within bovine post-compaction embryos incubated under two oxygen concentrations (7% versus 20%). Hum Reprod 2017; 32:2016-2025. [DOI: 10.1093/humrep/dex261] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 07/26/2017] [Indexed: 01/22/2023] Open
Affiliation(s)
- Melanie L. Sutton-McDowall
- Robinson Research Institute, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Martin Gosnell
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics
- Quantitative Pty Ltd, Mount Victoria, New South Wales 2786, Australia
| | - Ayad G. Anwer
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics
- Macquarie University, North Ryde, New South Wales 2109, Australia
| | - Melissa White
- Robinson Research Institute, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Malcolm Purdey
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, South Australia 5005, Australia
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Andrew D. Abell
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, South Australia 5005, Australia
- Department of Chemistry, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Ewa M. Goldys
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics
| | - Jeremy G. Thompson
- Robinson Research Institute, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics
- Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, South Australia 5005, Australia
| |
Collapse
|
18
|
Totipotency segregates between the sister blastomeres of two-cell stage mouse embryos. Sci Rep 2017; 7:8299. [PMID: 28811525 PMCID: PMC5557898 DOI: 10.1038/s41598-017-08266-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/06/2017] [Indexed: 11/09/2022] Open
Abstract
Following fertilization in mammals, it is generally accepted that totipotent cells are exclusive to the zygote and to each of the two blastomeres originating from the first mitotic division. This model of totipotency was inferred from a minority of cases in which blastomeres produced monozygotic twins in mice. Was this due to experimental limitation or biological constraint? Here we removed experimental obstacles and achieved reliable quantification of the prevalence of dual totipotency among mouse two-cell stage blastomeres. We separated the blastomeres of 1,252 two-cell embryos, preserving 1,210 of the pairs. Two classes of monozygotic twins became apparent at the blastocyst stage: 27% formed a functional epiblast in both members (concordant), and 73% did so in only one member of the pair (discordant) - a partition that proved insensitive to oocyte quality, sperm-entry point, culture environment and pattern of cleavage. In intact two-cell embryos, the ability of sister blastomeres to generate epiblast was also skewed. Class discovery clustering of the individual blastomeres' and blastocysts' transcriptomes points to an innate origin of concordance and discordance rather than developmental acquisition. Our data place constraints on the commonly accepted idea that totipotency is allocated equally between the two-cell stage blastomeres in mice.
Collapse
|
19
|
Li X, Zhang M, Pan X, Xu Z, Sun M. “Three Hits” Hypothesis for Developmental Origins of Health and Diseases in View of Cardiovascular Abnormalities. Birth Defects Res 2017; 109:744-757. [PMID: 28509412 DOI: 10.1002/bdr2.1037] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 03/24/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Xiang Li
- Institute for Fetology; First Hospital of Soochow University; Suzhou China
| | - Mengshu Zhang
- Institute for Fetology; First Hospital of Soochow University; Suzhou China
| | - Xinghua Pan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences
- Key Laboratory of Biochip Technology in Guangdong province; Southern Medical University; Guangzhou China
- Department of Genetics; Yale University School of Medicine; New Haven Connecticut
| | - Zhice Xu
- Institute for Fetology; First Hospital of Soochow University; Suzhou China
| | - Miao Sun
- Institute for Fetology; First Hospital of Soochow University; Suzhou China
| |
Collapse
|
20
|
Abstract
Epidemiological evidence links an individual's susceptibility to chronic disease in adult life to events during their intrauterine phase of development. Biologically this should not be unexpected, for organ systems are at their most plastic when progenitor cells are proliferating and differentiating. Influences operating at this time can permanently affect their structure and functional capacity, and the activity of enzyme systems and endocrine axes. It is now appreciated that such effects lay the foundations for a diverse array of diseases that become manifest many years later, often in response to secondary environmental stressors. Fetal development is underpinned by the placenta, the organ that forms the interface between the fetus and its mother. All nutrients and oxygen reaching the fetus must pass through this organ. The placenta also has major endocrine functions, orchestrating maternal adaptations to pregnancy and mobilizing resources for fetal use. In addition, it acts as a selective barrier, creating a protective milieu by minimizing exposure of the fetus to maternal hormones, such as glucocorticoids, xenobiotics, pathogens, and parasites. The placenta shows a remarkable capacity to adapt to adverse environmental cues and lessen their impact on the fetus. However, if placental function is impaired, or its capacity to adapt is exceeded, then fetal development may be compromised. Here, we explore the complex relationships between the placental phenotype and developmental programming of chronic disease in the offspring. Ensuring optimal placentation offers a new approach to the prevention of disorders such as cardiovascular disease, diabetes, and obesity, which are reaching epidemic proportions.
Collapse
Affiliation(s)
- Graham J Burton
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; and Department of Medicine, Knight Cardiovascular Institute, and Moore Institute for Nutrition and Wellness, Oregon Health and Science University, Portland, Oregon
| | - Abigail L Fowden
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; and Department of Medicine, Knight Cardiovascular Institute, and Moore Institute for Nutrition and Wellness, Oregon Health and Science University, Portland, Oregon
| | - Kent L Thornburg
- Centre for Trophoblast Research and Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom; and Department of Medicine, Knight Cardiovascular Institute, and Moore Institute for Nutrition and Wellness, Oregon Health and Science University, Portland, Oregon
| |
Collapse
|
21
|
Cagnone G, Sirard MA. The embryonic stress response to in vitro culture: insight from genomic analysis. Reproduction 2016; 152:R247-R261. [DOI: 10.1530/rep-16-0391] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/05/2016] [Indexed: 12/18/2022]
Abstract
Recent genomic studies have shed light on the impact of in vitro culture (IVC) on embryonic homeostasis and the differential gene expression profiles associated with lower developmental competence. Consistently, the embryonic stress responses to IVC conditions correlate with transcriptomic changes in pathways related to energetic metabolism, extracellular matrix remodelling and inflammatory signalling. These changes appear to result from a developmental adaptation that enhances a Warburg-like effect known to occur naturally during blastulation. First discovered in cancer cells, the Warburg effect (increased glycolysis under aerobic conditions) is thought to result from mitochondrial dysfunction. In the case of IVC embryos, culture conditions may interfere with mitochondrial maturation and oxidative phosphorylation, forcing cells to rely on glycolysis in order to maintain energetic homeostasis. While beneficial in the short term, such adaptations may lead to epigenetic changes with potential long-term effects on implantation, foetal growth and post-natal health. We conclude that lessening the detrimental effects of IVC on mitochondrial activity would lead to significantly improved embryo quality.
Collapse
|
22
|
Salvaing J, Peynot N, Bedhane MN, Veniel S, Pellier E, Boulesteix C, Beaujean N, Daniel N, Duranthon V. Assessment of 'one-step' versus 'sequential' embryo culture conditions through embryonic genome methylation and hydroxymethylation changes. Hum Reprod 2016; 31:2471-2483. [PMID: 27664206 PMCID: PMC5088634 DOI: 10.1093/humrep/dew214] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 07/26/2016] [Accepted: 08/04/2016] [Indexed: 12/13/2022] Open
Abstract
STUDY QUESTION In comparison to in vivo development, how do different conditions of in vitro culture (‘one step’ versus ‘sequential medium’) impact DNA methylation and hydroxymethylation in preimplantation embryos? SUMMARY ANSWER Using rabbit as a model, we show that DNA methylation and hydroxymethylation are both affected by in vitro culture of preimplantation embryos and the effect observed depends on the culture medium used. WHAT IS KNOWN ALREADY Correct regulation of DNA methylation is essential for embryonic development and DNA hydroxymethylation appears more and more to be a key player. Modifications of the environment of early embryos are known to have long term effects on adult phenotypes and health; these probably rely on epigenetic alterations. STUDY DESIGN SIZE, DURATION The study design we used is both cross sectional (control versus treatment) and longitudinal (time-course). Each individual in vivo experiment used embryos flushed from the donor at the 2-, 4-, 8-, 16- or morula stage. Each stage was analyzed in at least two independent experiments. Each individual in vitro experiment used embryos flushed from donors at the 1-cell stage (19 h post-coïtum) which were then cultured in parallel in the two tested media until the 2-, 4-, 8- 16-cell or morula stages. Each stage was analyzed in at least three independent experiments. In both the in vivo and in vitro experiments, 4-cell stage embryos were always included as an internal reference. PARTICIPANTS/MATERIALS, SETTING, METHODS Immunofluorescence with antibodies specific for 5-methylcytosine (5meC) and 5-hydroxymethylcytosine (5hmeC) was used to quantify DNA methylation and hydroxymethylation levels in preimplantation embryos. We assessed the expression of DNA methyltransferases (DNMT), of ten eleven translocation (TET) dioxigenases and of two endogenous retroviral sequences (ERV) using RT-qPCR, since the expression of endogenous retroviral sequences is known to be regulated by DNA methylation. Three repeats were first done for all stages; then three additional repetitions were performed for those stages showing differences or tendencies toward differences between the different conditions in the first round of quantification. MAIN RESULTS AND THE ROLE OF CHANCE The kinetics of DNA methylation and hydroxymethylation were modified in in vitro cultured embryos, and the observed differences depended on the type of medium used. These differences were statistically significant. In addition, the expression of TET1 and TET2 was significantly reduced in post-embryonic genome activation (EGA) embryos after in vitro culture in both tested conditions. Finally, the expression of two retroviral sequences was analyzed and found to be significantly affected by in vitro culture. LIMITATIONS REASONS FOR CAUTION Our study remains mostly descriptive as no direct link can be established between the epigenetic changes observed and the expression changes in both effectors and targets of the studied epigenetic modifications. The results we obtained suggest that gene expression could be affected on a large scale, but this remains to be confirmed. WIDER IMPLICATIONS OF THE FINDINGS Our results are in agreement with the literature, showing that DNA methylation is sensitive to in vitro culture. As we observed an effect of both tested culture conditions on the tested epigenetic marks and on gene expression, we cannot conclude which medium is potentially closest to in vivo conditions. However, as the observed effects are different, additional studies may provide more information and potential recommendations for the use of culture media in assisted reproductive technology. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by an ‘AMP diagnostic prénatal et diagnostic génétique’ 2012 grant from the French Agence de la Biomédecine. This study was performed within the framework of ANR LABEX ‘REVIVE’ (ANR-10-LABX-73). Authors are members of RGB-Net (TD 1101) and Epiconcept (FA 1201) COST actions. The authors declare that there is no competing interest.
Collapse
Affiliation(s)
- J Salvaing
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France .,UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - N Peynot
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - M N Bedhane
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France.,Present address: Jigjiga University, Ethiopia
| | - S Veniel
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - E Pellier
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France.,Present address: Faculté de Médecine, 27 Bd Jean Moulin, 13385 Marseille Cedex C5, France
| | - C Boulesteix
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - N Beaujean
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France.,Present address: INSERM U1208, INRA USC1361 Stem Cell and Brain Research Institute Department of Pluripotent Stem Cells in Mammals, 18 avenue Doyen Lépine, 69675 Bron, France
| | - N Daniel
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| | - V Duranthon
- UMR BDR, INRA, ENVA, Université Paris Saclay, 78350 Jouy en Josas, France
| |
Collapse
|
23
|
Tan TC, Ritter LJ, Whitty A, Fernandez RC, Moran LJ, Robertson SA, Thompson JG, Brown HM. Gray level Co‐occurrence Matrices (GLCM) to assess microstructural and textural changes in pre‐implantation embryos. Mol Reprod Dev 2016; 83:701-13. [DOI: 10.1002/mrd.22680] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/27/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Tiffany C.Y. Tan
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- School of MedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Lesley J. Ritter
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- School of MedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Australian Research Council Centre of Excellence for Nanoscale Biophotonics (CNBP)University of AdelaideAdelaideSouth AustraliaAustralia
| | - Annie Whitty
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- School of MedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Renae C. Fernandez
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- School of MedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Lisa J. Moran
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Monash Centre for Health Research ImplementationSchool of Public Health and Preventative MedicineMonash UniversityMelbourneAustralia
| | - Sarah A. Robertson
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- School of MedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Jeremy G. Thompson
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- School of MedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Australian Research Council Centre of Excellence for Nanoscale Biophotonics (CNBP)University of AdelaideAdelaideSouth AustraliaAustralia
| | - Hannah M. Brown
- Robinson Research InstituteUniversity of AdelaideAdelaideSouth AustraliaAustralia
- School of MedicineUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Australian Research Council Centre of Excellence for Nanoscale Biophotonics (CNBP)University of AdelaideAdelaideSouth AustraliaAustralia
| |
Collapse
|
24
|
Boiani M, Cibelli JB. What we can learn from single-cell analysis in development. Mol Hum Reprod 2016; 22:160-71. [DOI: 10.1093/molehr/gaw014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
|
25
|
Thompson JG, Brown HM, Sutton-McDowall ML. Measuring embryo metabolism to predict embryo quality. Reprod Fertil Dev 2016; 28:41-50. [DOI: 10.1071/rd15340] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Measuring the metabolism of early embryos has the potential to be used as a prospective marker for post-transfer development, either alone or in conjunction with other embryo quality assessment tools. This is necessary to maximise the opportunity of couples to have a healthy child from assisted reproduction technology (ART) and for livestock breeders to efficiently improve the genetics of their animals. Nevertheless, although many promising candidate substrates (e.g. glucose uptake) and methods (e.g. metabolomics using different spectroscopic techniques) have been promoted as viability markers, none has yet been widely used clinically or in livestock production. Herein we review the major techniques that have been reported; these are divided into indirect techniques, where measurements are made from the embryo’s immediate microenvironment, or direct techniques that measure intracellular metabolic activity. Both have strengths and weaknesses, the latter ruling out some from contention for use in human ART, but not necessarily for use in livestock embryo assessment. We also introduce a new method, namely multi- (or hyper-) spectral analysis, which measures naturally occurring autofluorescence. Several metabolically important molecules have fluorescent properties, which we are pursuing in conjunction with improved image analysis as a viable embryo quality assessment methodology.
Collapse
|
26
|
Wale PL, Gardner DK. The effects of chemical and physical factors on mammalian embryo culture and their importance for the practice of assisted human reproduction. Hum Reprod Update 2015. [PMID: 26207016 DOI: 10.1093/humupd/dmv034] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Although laboratory procedures, along with culture media formulations, have improved over the past two decades, the issue remains that human IVF is performed in vitro (literally 'in glass'). METHODS Using PubMed, electronic searches were performed using keywords from a list of chemical and physical factors with no limits placed on time. Examples of keywords include oxygen, ammonium, volatile organics, temperature, pH, oil overlays and incubation volume/embryo density. Available clinical and scientific evidence surrounding physical and chemical factors have been assessed and presented here. RESULTS AND CONCLUSIONS Development of the embryo outside the body means that it is constantly exposed to stresses that it would not experience in vivo. Sources of stress on the human embryo include identified factors such as pH and temperature shifts, exposure to atmospheric (20%) oxygen and the build-up of toxins in the media due to the static nature of culture. However, there are other sources of stress not typically considered, such as the act of pipetting itself, or the release of organic compounds from the very tissue culture ware upon which the embryo develops. Further, when more than one stress is present in the laboratory, there is evidence that negative synergies can result, culminating in significant trauma to the developing embryo. It is evident that embryos are sensitive to both chemical and physical signals within their microenvironment, and that these factors play a significant role in influencing development and events post transfer. From the viewpoint of assisted human reproduction, a major concern with chemical and physical factors lies in their adverse effects on the viability of embryos, and their long-term effects on the fetus, even as a result of a relatively brief exposure. This review presents data on the adverse effects of chemical and physical factors on mammalian embryos and the importance of identifying, and thereby minimizing, them in the practice of human IVF. Hence, optimizing the in vitro environment involves far more than improving culture media formulations.
Collapse
Affiliation(s)
- Petra L Wale
- School of BioSciences, University of Melbourne, Parkville, Victoria, Australia Melbourne IVF, Melbourne, Victoria, Australia
| | - David K Gardner
- School of BioSciences, University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
27
|
Endoplasmic reticulum stress signaling in mammalian oocytes and embryos: life in balance. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 316:227-65. [PMID: 25805126 DOI: 10.1016/bs.ircmb.2015.01.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mammalian oocytes and embryos are exquisitely sensitive to a wide range of insults related to physical stress, chemical exposure, and exposures to adverse maternal nutrition or health status. Although cells manifest specific responses to various stressors, many of these stressors intersect at the endoplasmic reticulum (ER), where disruptions in protein folding and production of reactive oxygen species initiate downstream signaling events. These signals modulate mRNA translation and gene transcription, leading to recovery, activation of autophagy, or with severe and prolonged stress, apoptosis. ER stress signaling has recently come to the fore as a major contributor to embryo demise. Accordingly, agents that modulate or inhibit ER stress signaling have yielded beneficial effects on embryo survival and long-term developmental potential. We review here the mechanisms of ER stress signaling, their connections to mammalian oocytes and embryos, and the promising indications that interventions in this pathway may provide new opportunities for improving mammalian reproduction and health.
Collapse
|
28
|
Winterhager E, Kidder GM. Gap junction connexins in female reproductive organs: implications for women's reproductive health. Hum Reprod Update 2015; 21:340-52. [PMID: 25667189 DOI: 10.1093/humupd/dmv007] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/20/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Connexins comprise a family of ~20 proteins that form intercellular membrane channels (gap junction channels) providing a direct route for metabolites and signalling molecules to pass between cells. This review provides a critical analysis of the evidence for essential roles of individual connexins in female reproductive function, highlighting implications for women's reproductive health. METHODS No systematic review has been carried out. Published literature from the past 35 years was surveyed for research related to connexin involvement in development and function of the female reproductive system. Because of the demonstrated utility of genetic manipulation for elucidating connexin functions in various organs, much of the cited information comes from research with genetically modified mice. In some cases, a distinction is drawn between connexin functions clearly related to the formation of gap junction channels and those possibly linked to non-channel roles. RESULTS AND CONCLUSIONS Based on work with mice, several connexins are known to be required for female reproductive functions. Loss of connexin43 (CX43) causes an oocyte deficiency, and follicles lacking or expressing less CX43 in granulosa cells exhibit reduced growth, impairing fertility. CX43 is also expressed in human cumulus cells and, in the context of IVF, has been correlated with pregnancy outcome, suggesting that this connexin may be a determinant of oocyte and embryo quality in women. Loss of CX37, which exclusively connects oocytes with granulosa cells in the mouse, caused oocytes to cease growing without acquiring meiotic competence. Blocking of CX26 channels in the uterine epithelium disrupted implantation whereas loss or reduction of CX43 expression in the uterine stroma impaired decidualization and vascularization in mouse and human. Several connexins are important in placentation and, in the human, CX43 is a key regulator of the fusogenic pathway from the cytotrophoblast to the syncytiotrophoblast, ensuring placental growth. CX40, which characterizes the extravillous trophoblast (EVT), supports proliferation of the proximal EVTs while preventing them from differentiating into the invasive pathway. Furthermore, women with recurrent early pregnancy loss as well as those with endometriosis exhibit reduced levels of CX43 in their decidua. The antimalaria drug mefloquine, which blocks gap junction function, is responsible for increased risk of early pregnancy loss and stillbirth, probably due to inhibition of intercellular communication in the decidua or between trophoblast layers followed by an impairment of placental growth. Gap junctions also play a critical role in regulating uterine blood flow, contributing to the adaptive response to pregnancy. Given that reproductive impairment can result from connexin mutations in mice, it is advised that women suffering from somatic disease symptoms associated with connexin gene mutations be additionally tested for impacts on reproductive function. Better knowledge of these essential connexin functions in human female reproductive organs is important for safeguarding women's reproductive health.
Collapse
Affiliation(s)
- Elke Winterhager
- Institute of Molecular Biology, University of Duisburg-Essen, University Clinics, 45211 Essen, Germany
| | - Gerald M Kidder
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario and Children's Health Research Institute, London, Ontario N6C 2V5, Canada
| |
Collapse
|
29
|
Walker KJ, Green MP, Gardner DK. Spatial asynchronous transfer of cleavage-stage mouse embryos to the uterus compromises fetal development. Mol Reprod Dev 2015; 82:80. [DOI: 10.1002/mrd.22456] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/13/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Kathryn J Walker
- School of BioSciences; University of Melbourne; Parkville Victoria Australia
| | - Mark P Green
- School of BioSciences; University of Melbourne; Parkville Victoria Australia
| | - David K Gardner
- School of BioSciences; University of Melbourne; Parkville Victoria Australia
| |
Collapse
|