Noninvasive amino acid turnover predicts human embryo aneuploidy

Assisted reproduction technology has two significant problems: low success rates and multiple pregnancies. Because of these problems, the priority in IVF clinics is to develop a potential diagnostic test that can be used to select the embryos with the ultimate developmental competence. Aneuploidy screening as embryo selection criteria will ensure that the transferred embryos are euploid and high implantation rate. We hypothesize that aneuploidy in human preimplantation embryos could be discriminated by their amino acid metabolism profile in the spent culture media. Preimplantation genetic testing for aneuploidy results and spent embryo culture medium amino acid content were analyzed for 58 couples. The next-generation sequencing technique was used and coupled with TE biopsy. Forty euploid and 71 aneuploid blastocysts were evaluated. Embryos were cultured individually until day 5 or 6 of embryo development. Spent culture medium was collected after finishing the culture. There was no statistical difference between D3 and D5 embryo morphology between euploid and aneuploid embryos (p > .05). Eight amino acids, including SER, GLY, HIS, ARG, THR, ALA, PRO, and TYR, were detected in the culture medium from the blank control group, euploid group, and aneuploid group. Only TYR amino acid concentration was found significantly higher in the aneuploid group compared to the euploid group (p < .003). Tyrosine amino acid levels equal to and above 76.38 µmol/L could be considered aneuploid. Aneuploid embryos demonstrate altered amino acid turnover in vitro relative to euploid counterparts. A noninvasive method of amino acid profiling will be of value as a tool for routine preimplantation embryo selection among all patient groups.

The dawn of the future: 30 years from the first biopsy of a human embryo. The detailed history of an ongoing revolution

Following early studies showing no adverse effects, cleavage stage biopsy by zona drilling using acid Tyrode's solution, and removal of single blastomeres for preimplantation genetic testing (PGT) and identification of sex in couples at risk of X-linked disease, was performed by Handyside and colleagues in late 1989, and pregnancies reported in 1990. This method was later used for specific diagnosis of monogenic conditions, and a few years later also for chromosomal structural and/or numerical impairments, thereby establishing a valuable alternative option to prenatal diagnosis. This revolutionary approach in clinical embryology spread worldwide, and several other embryo biopsy strategies developed over three decades in a process that is still ongoing. The rationale of this narrative review is to outline the different biopsy approaches implemented across the years in the workflow of the IVF clinics that provided PGT: their establishment, the first clinical experiences, their downsides, evolution, improvement and standardization. The history ends with a glimpse of the future: minimally/non-invasive PGT and experimental embryo micromanipulation protocols. This grand theme review outlines a timeline of the evolution of embryo biopsy protocols, whose implementation is increasing worldwide together with the increasing application of PGT techniques in IVF. It represents a vade mecum especially for the past, present and upcoming operators and experts in this field to (re)live this history from its dawn to its most likely future.

Assisted conception in women of advanced maternal age

A delay in childbearing to later in life has increased the number of women of advanced maternal age (AMA) opting for assisted reproduction. Women should be made aware that there are age-related changes to fertility, including a decline in oocyte reserve and quality, in addition to an increase in the number of oocyte chromosomal aberrations. Success rates of assisted reproductive technology (ART) cycles decrease with advanced maternal age. There are different fertility options for women of AMA, including fertility preservation (oocyte or embryo freezing), in vitro fertilisation (IVF treatment) with or without preimplantation genetic screening and oocyte or embryo donation. Detailed counselling needs to be offered to these women with regard to the risks, success rates, ethical and legal implications of these fertility treatment options. Women of AMA should be screened for underlying medical conditions that could have an impact on maternal and neonatal morbidity and mortality.

Next-generation sequencing analysis of each blastomere in good-quality embryos: insights into the origins and mechanisms of embryonic aneuploidy in cleavage-stage embryos

PURPOSE

To explore the whole-chromosome status, origins, and mechanisms of chromosomal abnormalities in good-quality cleavage embryos using multiple annealing and looping-based amplification cycle (MALBAC) sequencing.

METHODS

The embryos studied came from7 patients (maternal aged 26-35) who had healthy birth from the same IVF cycles. These 21 frozen day 3 good-quality embryos were thawed and disaggregated into individual blastomere. Each blastomere was collected and analyzed by MALBAC sequencing.

RESULTS

Conclusive results were obtained from a high percentage of blastomeres (95.3%). A total of 46.6% of blastomeres were diploid, 53.4% were abnormal, and 28.0% had complex aneuploidy. Out of 21 embryos, 3 (14.3%) were normal and 18 (85.7%) were mosaics, showing the occurrence of mitotic errors; aneuploidy was confirmed in all cells of 4 of the 18 embryos, which showed the coexistence of meiotic errors. Conclusive results were obtained from all blastomeres of 15 embryos (71.4%, 15/21), which enabled us to reconstruct the cell lineage on the basis of the chromosomal content of the blastomeres in each division. There were 9 mitotic errors (8.7%, 9/103): nondisjunction accounted for 88.9% (8/9), and endoreplication accounted for 11.1% (1/9).

CONCLUSIONS

In good-quality embryos, there was a high rate and diverse array of chromosomal abnormalities. Morphological evaluation does not appear to assist in the reduction in meiotic errors from parental origins. Mitotic errors were common, and nondisjunction was found to be the main mechanism causing malsegregation during the cleavage divisions.

Prenatal and pre-implantation genetic diagnosis

The past decade has seen the development of technologies that have revolutionized prenatal genetic testing; that is, genetic testing from conception until birth. Genome-wide single-cell arrays and high-throughput sequencing analyses are dramatically increasing our ability to detect embryonic and fetal genetic lesions, and have substantially improved embryo selection for in vitro fertilization (IVF). Moreover, both invasive and non-invasive mutation scanning of the genome are helping to identify the genetic causes of prenatal developmental disorders. These advances are changing clinical practice and pose novel challenges for genetic counselling and prenatal care.

Mutations in PADI6 Cause Female Infertility Characterized by Early Embryonic Arrest

Early embryonic arrest is one of the major causes of female infertility. However, because of difficulties in phenotypic evaluation, genetic determinants of human early embryonic arrest are largely unknown. With the development of assisted reproductive technology, the phenotype of early human embryonic arrest can now be carefully evaluated. Here, we describe a consanguineous family with a recessive inheritance pattern of female infertility characterized by recurrent early embryonic arrest in cycles of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). We have identified a homozygous PADI6 nonsense mutation (c.1141C>T [p.Gln381(∗)]) that is responsible for the phenotype. Mutational analysis of PADI6 in a cohort of 36 individuals whose embryos displayed developmental arrest identified two affected individuals with compound-heterozygous mutations (c.2009_2010del [p.Glu670Glyfs(∗)48] and c.633T>A [p.His211Gln]; c.1618G>A [p.Gly540Arg] and c.970C>T [p.Gln324(∗)]). Immunostaining indicated a lack of PADI6 in affected individuals' oocytes. In addition, the amount of phosphorylated RNA polymerase II and expression levels of seven genes involved in zygotic genome activation were reduced in the affected individuals' embryos. This phenotype is consistent with Padi6 knockout mice. These findings deepen our understanding of the genetic basis of human early embryonic arrest, which has been a largely ignored Mendelian phenotype. Our findings lay the foundation for uncovering other genetic causes of infertility resulting from early embryonic arrest.

Clinical outcome of preimplantation genetic diagnosis and screening using next generation sequencing

Background

Next generation sequencing (NGS) is now being used for detecting chromosomal abnormalities in blastocyst trophectoderm (TE) cells from in vitro fertilized embryos. However, few data are available regarding the clinical outcome, which provides vital reference for further application of the methodology. Here, we present a clinical evaluation of NGS-based preimplantation genetic diagnosis/screening (PGD/PGS) compared with single nucleotide polymorphism (SNP) array-based PGD/PGS as a control.

Results

A total of 395 couples participated. They were carriers of either translocation or inversion mutations, or were patients with recurrent miscarriage and/or advanced maternal age. A total of 1,512 blastocysts were biopsied on D5 after fertilization, with 1,058 blastocysts set aside for SNP array testing and 454 blastocysts for NGS testing. In the NGS cycles group, the implantation, clinical pregnancy and miscarriage rates were 52.6% (60/114), 61.3% (49/80) and 14.3% (7/49), respectively. In the SNP array cycles group, the implantation, clinical pregnancy and miscarriage rates were 47.6% (139/292), 56.7% (115/203) and 14.8% (17/115), respectively. The outcome measures of both the NGS and SNP array cycles were the same with insignificant differences. There were 150 blastocysts that underwent both NGS and SNP array analysis, of which seven blastocysts were found with inconsistent signals. All other signals obtained from NGS analysis were confirmed to be accurate by validation with qPCR. The relative copy number of mitochondrial DNA (mtDNA) for each blastocyst that underwent NGS testing was evaluated, and a significant difference was found between the copy number of mtDNA for the euploid and the chromosomally abnormal blastocysts. So far, out of 42 ongoing pregnancies, 24 babies were born in NGS cycles; all of these babies are healthy and free of any developmental problems.

Conclusions

This study provides the first evaluation of the clinical outcomes of NGS-based pre-implantation genetic diagnosis/screening, and shows the reliability of this method in a clinical and array-based laboratory setting. NGS provides an accurate approach to detect embryonic imbalanced segmental rearrangements, to avoid the potential risks of false signals from SNP array in this study.

Electronic supplementary material

The online version of this article (doi:10.1186/2047-217X-3-30) contains supplementary material, which is available to authorized users.

[Update on preimplantation genetic diagnosis and screening]

Recent advancement in both human embryology and genomics has created a completely new situation for practical and widespread application of preimplantation genetic diagnosis and screening with a dramatic effect on assisted reproduction. The mapping of the first human genome and the advancement in sequencing technology and bioinformatics has led to the discovery of the exact genetic background of exponentially increasing number of diseases. In parallel, methods for culturing human embryos have also radically improved, enabling the late transfer, and the procedure of vitrification the safe cryopreservation. In consequence, refined genetic analyses have become available from blastocyst biopsy followed by the application of novel genomic methods. Furthermore, some studies suggest that by the selection of aneuploid embryos the pregnancy- and birth-rates can be increased. The amount and the depth of information obtainable from the embryos raise several technical and ethical questions that can be answered by further prospective randomized trials.

Preimplantation Genetic Diagnosis: Prenatal Testing for Embryos Finally Achieving Its Potential

Preimplantation genetic diagnosis was developed nearly a quarter-century ago as an alternative form of prenatal diagnosis that is carried out on embryos. Initially offered for diagnosis in couples at-risk for single gene genetic disorders, such as cystic fibrosis, spinal muscular atrophy and Huntington disease, preimplantation genetic diagnosis (PGD) has most frequently been employed in assisted reproduction for detection of chromosome aneuploidy from advancing maternal age or structural chromosome rearrangements. Major improvements have been seen in PGD analysis with movement away from older, less effective technologies, such as fluorescence in situ hybridization (FISH), to newer molecular tools, such as DNA microarrays and next generation sequencing. Improved results have also started to be seen with decreasing use of Day 3 blastomere biopsy in favor of polar body or Day 5 trophectoderm biopsy. Discussions regarding the scientific, ethical, legal and social issues surrounding the use of sequence data from embryo biopsy have begun and must continue to avoid concern regarding eugenic or inappropriate use of this technology.

Comprehensive embryo testing. Experts' opinions regarding future directions: an expert panel study on comprehensive embryo testing

STUDY QUESTION

What do scientists in the field of preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS) consider to be the future direction of comprehensive embryo testing?

SUMMARY ANSWER

Although there are many biological and technical limitations, as well as uncertainties regarding the meaning of genetic variation, comprehensive embryo testing will impact the IVF/PGD practice and a timely ethical reflection is needed.

WHAT IS KNOWN ALREADY

Comprehensive testing using microarrays is currently being introduced in the context of PGD and PGS, and it is to be expected that whole-genome sequencing will also follow. Current ethical and empirical sociological research on embryo testing focuses on PGD as it is practiced now. However, empirical research and systematic reflection regarding the impact of comprehensive techniques for embryo testing is missing.

STUDY DESIGN, SIZE AND DURATION

In order to understand the potential of this technology and to be able to adequately foresee its implications, we held an expert panel with seven pioneers in PGD.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We conducted an expert panel in October 2011 with seven PGD pioneers from Belgium, The Netherlands, Germany and the UK.

MAIN RESULTS AND THE ROLE OF CHANCE

Participants expected the use of comprehensive techniques in the context of PGD. However, the introduction of these techniques in embryo testing requires timely ethical reflection as it involves a shift from choosing an embryo without a particular genetic disease (i.e. PGD) or most likely to result in a successful pregnancy (i.e. PGS) to choosing the best embryo based on a much wider set of criteria. Such ethical reflection should take account of current technical and biological limitations and also of current uncertainties with regard to the meaning of genetic variance. However, ethicists should also not be afraid to look into the future. There was a general agreement that embryo testing will be increasingly preceded by comprehensive preconception screening, thus enabling smart combinations of genetic testing.

LIMITATIONS, REASONS FOR CAUTION

The group was composed of seven participants from four Western Europe countries. As willingness to participate in this study may be connected with expectations regarding the pace and direction of future developments, selection bias cannot be excluded.

WIDER IMPLICATIONS OF THE FINDINGS

The introduction of comprehensive screening techniques in embryo testing calls for further ethical reflection that is grounded in empirical work. Specifically, there is a need for studies querying the opinions of infertile couples undergoing IVF/PGS regarding the desirability of embryo screening beyond aneuploidy.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the CSG, Centre for Society and Life Sciences (project number: 70.1.074). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

ESHRE PGD Consortium data collection XI: cycles from January to December 2008 with pregnancy follow-up to October 2009

The 11th report of the European Society of Human Reproduction and Embryology Preimplantation Genetic Diagnosis Consortium is presented, documenting cycles collected for the calendar year 2008 and follow-up of the pregnancies and babies born until October 2009 which resulted from these cycles. Since the beginning of the data collections, there has been a steady increase in the number of cycles, pregnancies and babies reported annually. For data collection XI, 53 centres have participated, reporting on 5641 cycles to oocyte retrieval (OR), along with details of the follow-up on 1418 pregnancies and 1169 babies born. A total of 774 OR were reported for chromosomal abnormalities, 96 OR for sexing for X-linked diseases, 1363 OR for monogenic diseases, 3401 OR for preimplantation genetic screening and 5 OR for social sexing. Data XI is compared with the cumulative data for data collections I-X.

PGS-FISH in reproductive medicine and perspective directions for improvement: a systematic review

INTRODUCTION

Embryo selection can be carried out via morphological criteria or by using genetic studies based on Preimplantation Genetic Screening. In the present study, we evaluate the clinical validity of Preimplantation Genetic Screening with fluorescence in situ hybridization (PGS-FISH) compared with morphological embryo criteria.

MATERIAL AND METHODS

A systematic review was made of the bibliography, with the following goals: firstly, to determine the prevalence of embryo chromosome alteration in clinical situations in which the PGS-FISH technique has been used; secondly, to calculate the statistics of diagnostic efficiency (negative Likelihood Ratio), using 2 × 2 tables, derived from PGS-FISH. The results obtained were compared with those obtained from embryo morphology. We calculated the probability of transferring at least one chromosome-normal embryo when it was selected using either morphological criteria or PGS-FISH, and considered what diagnostic performance should be expected of an embryo selection test with respect to achieving greater clinical validity than that obtained from embryo morphology.

RESULTS

After an embryo morphology selection that produced a negative result (normal morphology), the likelihood of embryo aneuploidies was found to range from a pre-test value of 65% (prevalence of embryo chromosome alteration registered in all the study groups) to a post-test value of 55% (Confidence interval: 50-61), while after PGS-FISH with a negative result (euploid), the post-test probability was 42% (Confidence interval: 35-49) (p < 0.05). The probability of transferring at least one euploid embryo was the same whether 3 embryos were selected according to morphological criteria or whether 2, selected by PGS-FISH, were transferred. Any embryo selection test, if it is to provide greater clinical validity than embryo morphology, must present a LR-value of 0.40 (Confidence interval: 0.32-0.51) in single embryo transfer, and 0.06 (CI: 0.05-0.07) in double embryo transfer.

DISCUSSION

With currently available technology, and taking into account the number of embryos to be transferred, the clinical validity of PGS-FISH, although superior to that of morphological criteria, does not appear to be clinically relevant.

ESHRE PGD consortium best practice guidelines for organization of a PGD centre for PGD/preimplantation genetic screening

In 2005, the European Society for Human Reproduction and Embryology (ESHRE) PGD Consortium published a set of Guidelines for Best Practice PGD to give information, support and guidance to potential, existing and fledgling PGD programmes. Subsequent years have seen the introduction of new technologies as well as the evolution of current techniques. Additionally, in light of recent advice from ESHRE on how practice guidelines should be written/formulated, the Consortium believed it was timely to update the PGD guidelines. Rather than one document that covers all of PGD, the new guidelines are separated into four documents, including one relating to organization of the PGD centre and three relating to the methods used: DNA amplification, fluorescence in situ hybridization and biopsy/embryology. Here, we have updated the sections on organization of the PGD centre. One area that has continued to expand is Transport PGD, in which patients are treated at one IVF centre, whereas their gametes/embryos are tested elsewhere, at an independent PGD centre. Transport PGD/preimplantation genetic screening (PGS) has a unique set of challenges with respect to the nature of the sample and the rapid turn-around time required. PGS is currently controversial. Opinions of laboratory specialists and clinicians interested in PGD and PGS have been taken into account here. Current evidence suggests that PGS at cleavage stages is ineffective, but whether PGS at the blastocyst stage or on polar bodies might show improved delivery rates is still unclear. Thus, in this revision, PGS has been included. This document should assist everyone interested in PGD/PGS in developing the best laboratory and clinical practice possible.

ESHRE PGD Consortium data collection X: cycles from January to December 2007 with pregnancy follow-up to October 2008

The 10th report of the European Society of Human Reproduction and Embryology (ESHRE) PGD Consortium is presented, documenting cycles collected for the calendar year 2007 and follow-up of the pregnancies and babies born until October 2008 which resulted from these cycles. Since the beginning of the data collections there has been a steady increase in the number of cycles, pregnancies and babies reported annually. For data collection X, 57 centres participated, reporting on 5887 cycles to oocyte retrieval (OR), along with details of the follow-up on 1516 pregnancies and 1206 babies born. A total of 729 OR were reported for chromosomal abnormalities, 110 OR for sexing for X-linked diseases, 1203 OR for monogenic diseases, 3753 OR for preimplantation genetic screening and 92 OR for social sexing. Data X is compared with the cumulative data for data collections I-IX.

Association between amino acid turnover and chromosome aneuploidy during human preimplantation embryo development in vitro

This study investigated the relationship between human preimplantation embryo metabolism and aneuploidy rates during development in vitro. One hundred and eighty-eight fresh and cryopreserved embryos from 59 patients (33.9 +/- 0.6 years) were cultured for 2-5 days. The turnover of 18 amino acids was measured in spent media by high-performance liquid chromatography. Embryos were either fixed for interphase fluorescent in situ hybridization analysis of chromosomes 13, 18, 19, 21, X or Y, or were assayed for mitochondrial activity. Amino acid turnover was different (P < 0.05) between stage-matched fresh and cryopreserved embryos due to blastomere loss following warming. The proportion of embryos with aneuploid cells increased as cell division progressed from pronucleate- (23%) to late cleavage stages (50-70%). Asparagine, glycine and valine turnover was significantly different between uniformly genetically normal and uniformly abnormal embryos on Days 2-3 of culture. By Days 3-4, the profiles of serine, leucine and lysine differed between uniformly euploid versus aneuploid embryos. Gender significantly (P < 0.05) affected the metabolism of tryptophan, leucine and asparagine by cleavage-stage embryos. Pronucleate zygotes had a significantly higher proportion of active:inactive mitochondria compared with cleavage-stage embryos. Furthermore, mitochondrial activity was correlated (P < 0.05) with altered aspartate and glutamine turnover. These results demonstrate the association between the metabolism, cytogenetic composition and health of human embryos in vitro.

Preimplantation genetic screening: an effective testing for infertile and repeated miscarriage patients?

Aneuploidy in pregnancy is known to increase with advanced maternal age (AMA) and associate with repeated implantation failure (RIF), and repeated miscarriage (RM). Preimplantation genetic screening (PGS) has been introduced into clinical practice, screening, and eliminating aneuploidy embryos, which can improve the chance of conceptions for infertility cases with poor prognosis. These patients are a good target group to assess the possible benefit of aneuploidy screening. Although practiced widely throughout the world, there still exist some doubts about the efficacy of this technique. Recent randomized trials were not as desirable as we expected, suggesting that PGS needs to be reconsidered. The aim of this review is to discuss the efficacy of PGS.

The use of arrays in preimplantation genetic diagnosis and screening

BACKGROUND

In preimplantation genetic diagnosis (PGD), polymerase chain reaction has been used to detect monogenic disorders, and in PGD/preimplantation genetic screening (PGS), fluorescence in situ hybridization (FISH) has been used to analyze chromosomes. Ten randomized controlled trials (RCTs) using FISH-based PGS on cleavage-stage embryos and one on blastocyst-stage embryos have shown that PGS does not increase delivery rates. Is the failure of PGS due to a fundamental flaw in the idea, or are the techniques that are being used unable to overcome their own, inherent flaws? Array-based technology allows for analysis of all of the chromosomes. Two types of arrays are being developed for use in PGD; array comparative genomic hybridization (aCGH) and single nucleotide polymorphism-based (SNP) arrays. Each array can determine the number of chromosomes, however, SNP-based arrays can also be used to haplotype the sample.

OBJECTIVE(S)

To describe aCGH and SNP array technology and make suggestions for the future use of arrays in PGD and PGS.

CONCLUSION(S)

If array-based testing is going to prove useful, three steps need to be taken: [1] Validation of the array platform on appropriate cell and tissue samples to allow for reliable testing, even at the single-cell level; [2] deciding which embryo stage is the best for biopsy: polar body, cleavage, or blastocyst stage; [3] performing RCTs to show improvement in delivery rates. If RCTs are able to show that array-based testing at the optimal stage for embryo biopsy increases delivery rates, this will be a major step forward for assisted reproductive technology patients around the world.

Slow and ultrarapid cryopreservation of biopsied mouse blastocysts and its effect on DNA integrity index

PURPOSE

To evaluate the effect of slow and ultra-rapid freezing on biopsied blastocysts' DNA integrity.

METHODS

Forty eight mouse blastocysts were biopsied of which 16 were cryopreserved by slowly freezing and 17 by vitrification. Fourteen intact blastocysts were slowly cryopreserved and 24 were vitrified. Eighteen fresh intact blastocysts and fifteen biopsied blastocysts served as controls. The DNA integrity index of all blastocysts was evaluated using (TUNEL) staining and confocal imaging

RESULTS

Both slow freezing and vitrification of biopsied blastocysts induced apoptosis to a similar extent. Biopsying blastocysts before vitrification resulted in less apoptosis than vitrification of intact blastocysts.

CONCLUSION

Slow freezing and vitrification are equal options for preservation of biopsied blastocysts as regards the DNA integrity index (DII). Biopsied blastocysts better tolerate vitrification than intact expanded blastocysts.

Y chromosome microdeletions, sperm DNA fragmentation and sperm oxidative stress as causes of recurrent spontaneous abortion of unknown etiology

BACKGROUND

The aim of the present study was to evaluate the implication of male factor, in terms of sperm DNA oxidation and fragmentation, and Y chromosome microdeletions in recurrent spontaneous abortion (RSA) of unknown origin in a strictly selected cohort.

METHODS

A prospective cohort study was carried out in a private university-affiliated setting. Three groups, each comprised of 30 males, were compared. The first was formed by healthy and fertile sperm donors (SD) with normal sperm parameters (control group), the second by men presenting severe oligozoospermia (SO) without RSA history, and the third by men from couples who had experienced idiopathic RSA. Frequency of Y chromosome microdeletions and mean sperm DNA fragmentation and oxidation were determined.

RESULTS

Y chromosome microdeletions were not detected in any of the males enrolled in the study. Moreover, sperm DNA oxidation measurements were not demonstrated to be relevant to RSA. Interestingly, sperm DNA fragmentation was higher in the SO group than in the RSA and the SD groups, and also higher in the RSA group compared with the SD group, but lacked an adequate predictive power to be employed as a discriminative test of RSA condition.

CONCLUSIONS

Sperm DNA features and Y chromosome microdeletions do not seem to be related to RSA of unknown origin. Other molecular features of sperm should be studied to determine their possible influence on RSA. Clinicaltrials.gov reference: NCT00447395.

Are zona pellucida laser drilling and polar body biopsy safe for in vitro matured oocytes?

INTRODUCTION

Preconception diagnosis requires first polar body biopsy. When the hole in the zona pellucida is made with a laser beam, heat propagation could, like the biopsy itself, be deleterious. Our aim was to evaluate the effect of this technique on human in vitro matured oocyte and embryo development.

METHODS

One hunded fifty five retrieved immature oocytes from 75 women, matured in vitro, were distributed in 3 groups: 50 oocytes in a control group, without laser drilling and first polar body biopsy, 52 oocytes in a group with only laser drilling, and 53 oocytes in a group with both laser drilling and first polar body biopsy. Safety was evaluated using four criteria: [1] oocyte lysis rate, [2] oocyte activation rate, [3] oocyte development after calcium ionophore treatment, [4] and embryo chromosome breakage incidence after Tarkowski preparation.

RESULTS

No difference in the four criteria was observed between the 3 oocyte groups.

CONCLUSIONS

We did not find evidence of deleterious effect of laser drilling and first polar body biopsy on in vitro matured oocytes, according to our criteria.

Preimplantation genetic diagnosis for stargardt disease

PURPOSE

To report the first use of in vitro fertilization (IVF) and preimplantation genetic diagnosis to achieve an unaffected pregnancy in an autosomal-recessive retinal dystrophy.

DESIGN

Case report.

METHODS

An affected male with Stargardt disease and his carrier wife underwent IVF. Embryos obtained by intracytoplasmic sperm injection underwent single-cell DNA testing via polymerase chain reaction and restriction enzyme analysis to detect the presence of ABCA4 mutant alleles. Embryos were diagnosed as being either affected by or carriers for Stargardt disease. A single carrier embryo was implanted.

RESULTS

Chorionic villus sampling performed during the first trimester verified that the fetus possessed only 1 mutant paternal allele and 1 normal maternal allele, thus making her an unaffected carrier of the disease. A healthy, live-born female was delivered.

CONCLUSION

IVF and preimplantation genetic diagnosis can assist couples with an affected spouse and a carrier spouse with recessive retinal dystrophies to have an unaffected child.

Sex and reproduction: an evolving relationship

BACKGROUND

Although sexual activity has, until very recently, been essential to reproduction, this did not preclude the non-reproductive importance of sexual relationships and non-conceptive copulations. Technological advances, however, now allow for both sex without reproduction and reproduction without sex. This review summarizes social and ethical commentaries on the new relationship between sex and reproduction.

METHODS

For each main area discussed, a systematic search was made using (depending on the subject) PubMed, Medline, ScienceDirect, classic books, Google and/or religious websites. The search focused on publications between 1975 and 2009, although some materials from the first part of the 20th century were also utilized.

RESULTS

The classic picture of sex for reproduction and bonding between mating partners is increasingly being replaced by reproduction separate from sexual activity. Although not every advance in assisted reproduction produced, per se, a further separation from sexual intercourse, these two fundamental human activities are today increasingly carried out independently, as reproduction is possible, not only without sex, but even through the intervention of more than two partners. The possibility of reproduction with only one or even no gametes, although highly controversial and not yet feasible, is nonetheless being investigated.

CONCLUSIONS

Technological advances in the field of reproductive biology have enabled couples considered infertile to conceive and have healthy babies, causing a revolution in culture and customs. Today the independence of sex and reproduction is established and in the future human reproduction may move even further away from the sexual act, an option definitely unacceptable to some ethicists.

The role of preimplantation genetic diagnosis in diagnosing embryo aneuploidy

PURPOSE OF REVIEW

Use of preimplantation genetic diagnosis to improve in-vitro fertilization outcomes is reviewed.

RECENT FINDINGS

Many embryos produced in vitro contain chromosomal abnormalities and have little potential for forming a viable pregnancy. The most commonly used method for preimplantation genetic diagnosis involves embryo biopsy on day 3 of development, followed by fluorescence in-situ hybridization analysis of 5-12 chromosomes. However, positive results have been more common with single-cell biopsy and the analysis of nine or more chromosomes, including 15, 16, 21, and 22. Comparative genomic hybridization, array-comparative genomic hybridization, and single-nucleotide polymorphism arrays analyze all chromosomes and, although technically demanding and requiring experience for successful use, improve the selection potential of preimplantation genetic diagnosis and minimize error rates. Recent data suggest that biopsy at the blastocyst stage may allow sampling of representative genetic material without compromising embryo viability. The optimal strategy for aneuploidy screening using preimplantation genetic diagnosis seems to be blastocyst biopsy at 5 days and comprehensive chromosome analysis (comparative genomic hybridization, array-comparative genomic hybridization, single-nucleotide polymorphism array).

SUMMARY

The use of preimplantation genetic diagnosis to assist the identification and preferential transfer of healthy euploid embryos should improve implantation rates, reduce miscarriages and trisomic offspring, and ultimately lead to an increase in live birth rates.

Psychological impact of preimplantation genetic diagnosis: a review of the literature

Preimplantation genetic diagnosis (PGD) was first reported as successful in humans in the early 1990s and nearly two decades later the psychological impact of PGD has not yet been clearly defined. As PGD requires the use of IVF, this paper provides a brief summary of literature related to the various psychological aspects of IVF followed by a review of the literature related to the psychological and broader psychosocial impact of PGD. The current literature includes attitudinal studies of couples for whom PGD may be beneficial and results suggest that those with traumatic reproductive and genetic histories are more likely to find PGD an acceptable treatment option. A small number of studies have used samples of women and couples who have used PGD. Due to a general lack of homogeneity in scope, method and results, these studies have not provided a uniform understanding of the PGD experience. Promisingly, however, two studies on parents of children born after PGD that explored parental stress show no differences between PGD, IVF and natural conception couples. The paper concludes that the missing link in the literature is a prospective study of PGD using validated psychological scales. Suggestions for future research are provided.

Quantitative decision-making in preimplantation genetic (aneuploidy) screening (PGS)

PURPOSE

To analyze using hypergeometric probability statistics the impact of performing preimplantation genetic screening (PGS) on a cohort of day 3 cleavage stage embryos.

METHODS

Statistical mathematical modeling.

RESULTS

We find the benefit of performing PGS is highly dependent on the number of day 3 embryos available for biopsy. Additional hidden variables that determine the outcome of PGS are the rates of aneuploidy and mosaicism, and the probability of a chromosomally mosaic embryo to test "normal". If PGS is performed, our analysis shows that many combinations of the number of biopsiable embryos, and the rates of aneuploidy and mosaicism results in a marginal benefit from the intervention. Other combinations are detrimental if PGS is actually undertaken. Finally, increases in PGS error rates lead to a rapid loss in the ability of PGS to provide useful discriminatory information.

CONCLUSION

We set out the statistical framework to determine the limits of PGS when a specific number of day 3 preimplantation embryos are available for biopsy. In general, PGS cannot be recommended a priori for a specific clinical situation due to the statistical uncertainties associated with the different hidden variable quantitative parameters considered important to the clinical outcome.

What next for preimplantation genetic screening? High mitotic chromosome instability rate provides the biological basis for the low success rate

Preimplantation genetic screening is being scrutinized, as recent randomized clinical trials failed to observe the expected significant increase in live birth rates following fluorescence in situ hybridization (FISH)-based screening. Although these randomized clinical trials are criticized on their design, skills or premature stop, it is generally believed that well-designed and well-executed randomized clinical trials would resolve the debate about the potential benefit of preimplantation genetic screening. Since FISH can analyze only a limited number of chromosomal loci, some of the embryos transferred might be diagnosed as ‘normal’ but in fact be aneuploid for one or more chromosomes not tested. Hence, genome-wide array comparative genome hybridization screening enabling aneuploidy detection of all chromosomes was thought to be a first step toward a better design. We recently showed array screening indeed enables accurate determination of the copy number state of all chromosomes in a single cell. Surprisingly, however, this genome-wide array screening revealed a much higher frequency and complexity of chromosomal aberrations in early embryos than anticipated, with imbalances in a staggering 90% of all embryos. The mitotic error rate in cleavage stage embryos was proven to be higher than the meiotic aneuploidy rate and as a consequence, the genome of a single blastomere is not representative for the genome of the other cells of the embryo. Hence, potentially viable embryos will be discarded upon screening a single blastomere. This observation provides a biological basis for the failure of the randomized clinical trials to increase baby-take-home rates using FISH on cleavage stage embroys.

Technology requirements for preimplantation genetic diagnosis to improve assisted reproduction outcomes

Preimplantation genetic diagnosis has been proposed as a method to improve assisted reproduction technology outcomes, but different techniques have produced conflicting results. The use of appropriate techniques may provide positive outcomes.

ESHRE PGD Consortium data collection IX: cycles from January to December 2006 with pregnancy follow-up to October 2007

The ninth report of the European Society of Human Reproduction and Embryology Preimplantation Genetic Diagnosis Consortium is presented documenting cycles collected for the calendar year 2006 and follow-up of the pregnancies and babies born until October 2007, which resulted from these cycles. Since the beginning of the data collections there has been a steady increase in the number of cycles, pregnancies and babies reported annually. For data collection IX, 57 centres have participated, reporting on 5858 cycles to oocyte retrieval (OR), along with details of the follow-up on 1437 pregnancies and 1206 babies born. Eight hundred and twelve ORs were reported for chromosomal abnormalities, 133 ORs for sexing for X-linked diseases, 931 ORs for monogenic diseases, 3900 ORs for preimplantation genetic screening and 82 ORs for social sexing. Data IX are compared with the cumulative data for data collections I-VIII.

Providing preimplantation genetic diagnosis in the United Kingdom, The Netherlands and Germany: a comparative in-depth analysis of health-care access

In recent years, preimplantation genetic diagnosis (PGD) has developed into a routine diagnostic procedure in health care. Although during this process, several initiatives have been employed to regulate the procedure, access to PGD may be hampered by the diversity in health-care arrangements or therapeutic cultures in different countries. This article demonstrates how PGD provision practices depend on much more than regulation alone, by providing an in-depth comparative analysis of the provision of PGD in Britain, the Netherlands and Germany. In analysing regulation, organization, selection of indications, and mechanisms and criteria for reimbursement, differences between these countries can be identified. This is important, since differences in PGD provision can have enormous consequences for the access of individual patients in different countries. Somewhat paradoxically, this article concludes that even though differences in access do have serious consequences, they also serve the establishment of PGD. Developing access to PGD in national 'therapeutic cultures' can contribute to making PGD routine health care in a way that may not be achievable by harmonizing regulation.

[Mastenbroek controversy or how much ink is spilled on preimplantation genetic screening subject]

Preimplantation genetic screening (PGS) of in vitro fertilization (IVF) embryos has been used for advanced maternal age, repeated miscarriages and repeated implantation failure indications. Several non-randomized studies have been published, showing increased implantation rates, decreased miscarriages and trisomy rates. So PGS seemed to improve prognosis for this particular population. In 2004, a prospective randomized study tempered those results, being unable to demonstrate any significant difference of live birth rate with and without PGS in case of advanced maternal age. In July 2007, another multicenter randomized double-blind trial definitely reopened the controversy, reporting that PGS did not increase but instead significantly reduced pregnancy and live birth rates after IVF in women 35 years of age or older. The debate about efficiency and usefulness of PGS is ongoing and other powered randomized studies will be needed to conclude about real PGS usefulness.

Elective single embryo transfer: guidelines for practice British Fertility Society and Association of Clinical Embryologists

Assisted conception treatment is the single most important cause in the increase in multiple pregnancy and births over the last 25 years. Multiple births are associated with significant peri natal morbidity and mortality. Europe has led the way in reducing multiple births by widespread adoption of an elective single embryo policy, which in Belgium is linked to an increase in state funding. Randomized controlled trials suggest that an eSET policy must include the ability to cryopreserve and transfer any remaining quality embryos to obtain parity with a double embryo transfer. This document provides a review of the available evidence with guidelines for practice, to help facilitate the introduction of an eSET policy in the UK.

What next for preimplantation genetic screening? More randomized controlled trials needed?

The recent debate on preimplantation genetic screening (PGS) has raised questions about its routine use in clinical practice. It has been suggested that the most effective way to resolve the debate about the usefulness of PGS is to perform more well-designed and well-executed randomized controlled trials (RCTs). However, in view of the lack of evidence for the effectiveness of PGS and the accumulating evidence for its harmfulness, it is our opinion that it is unethical to perform additional RCTs for the indication advanced maternal age using cleavage stage biopsy.

Preimplantation aneuploid embryos undergo self-correction in correlation with their developmental potential

OBJECTIVE

To investigate the incidence of embryos' self-correction during preimplantation development in terms of mosaicism and in correlation with its developmental stage.

DESIGN

Prospective study to compare the chromosome status of embryos on day 3 with that of day 5, in correlation with their developmental stage.

SETTING

In vitro fertilization unit of a university-affiliated hospital.

PATIENT(S)

Eighty-three aneuploid embryos.

INTERVENTION(S)

Fluorescence in situ hybridization (FISH) reanalysis.

MAIN OUTCOME MEASURE(S)

Day 3 embryos classified as mosaic or chromosomally abnormal by preimplantation genetic screening (PGS) were reanalyzed on day 5. The results were evaluated in correlation with the embryos' developmental stage.

RESULT(S)

Out of 83 day 3 aneuploid embryos, 15 (18.1%) were diagnosed with mosaicism. The FISH reanalysis on day 5 demonstrated that 27 embryos (32.6%) were partly or entirely normal disomic. Of these 83 aneuploid embryos, 8 (9.7%) underwent complete self-correction. The PGS results demonstrated that 26.5% of the embryos were trisomic, of which 41.0% underwent trisomic rescue by day 5. Self-correction was in correlation with the embryo's developmental stage, i.e., 38.1% of aneuploid embryos that developed to the blastocyst stage underwent self-correction compared with only 12.5% of embryos that only cleaved after biopsy.

CONCLUSION(S)

Our results demonstrate that self-correction of aneuploid and mosaic embryos occurs probably more significantly during development toward the blastocyst stage than in delayed embryos. In addition, trisomic embryos correct themselves more than other aneuploidies. These findings suggest that PGS results must be interpreted with caution.

ESHRE PGD Consortium data collection VIII: cycles from January to December 2005 with pregnancy follow-up to October 2006

The eighth report of the European Society of Human Reproduction and Embryology PGD Consortium is presented documenting cycles collected for the calendar year 2005 and follow-up of the pregnancies and babies born until October 2006 which resulted from these cycles. For the first time, the delivery rates for each indication are presented and also the pregnancy rates for each centre are reported anonymously. Since the first data collections, there has been a steady increase in the number of cycles, pregnancies and babies reported annually. For data collection VIII, 39 centres have participated, reporting on 3488 cycles to oocyte retrieval (OR), along with details of the follow-up on 845 pregnancies and 670 babies born. Five hundred and twenty OR were reported for chromosomal abnormalities, 108 OR for sexing for X-linked diseases, 500 OR for monogenic diseases, 2275 OR for preimplantation genetic screening and 85 OR for social sexing. Data VIII is compared with the cumulative data for data collections I-VII.

What next for preimplantation genetic screening? Randomized clinical trial in assessing PGS: necessary but not sufficient

The randomized clinical trial (RCT) is a powerful experimental design that when properly executed produces generalizable results. Conducting a RCT becomes complex when technical skills are required. Without requisite skills, a RCT may yield misleading results, an elegant RCT unwittingly generating spurious results due to technical inexperience. This pitfall is applicable to procedures used to evaluate assisted reproductive technologies. RCTs assessing the value of preimplantation genetic screening, also called preimplantation genetic diagnosis for aneuploidy testing--require three general prerequisites--proper study design, skilled operators (embryo biopsy), and skilled laboratory cytogeneticists (diagnosis). Lacking either of the latter two, even an elegantly designed RCT is not necessarily valid.