The social formation of fitness: lifetime consequences of prenatal nutrition and postnatal care in a wild mammal population

Research in medicine and evolutionary biology suggests that the sequencing of parental investment has a crucial impact on offspring life history and health. Here, we take advantage of the synchronous birth system of wild banded mongooses to test experimentally the lifetime consequences to offspring of receiving extra investment prenatally versus postnatally. We provided extra food to half of the breeding females in each group during pregnancy, leaving the other half as matched controls. This manipulation resulted in two categories of experimental offspring in synchronously born litters: (i) 'prenatal boost' offspring whose mothers had been fed during pregnancy, and (ii) 'postnatal boost' offspring whose mothers were not fed during pregnancy but who received extra alloparental care in the postnatal period. Prenatal boost offspring lived substantially longer as adults, but postnatal boost offspring had higher lifetime reproductive success (LRS) and higher glucocorticoid levels across the lifespan. Both types of experimental offspring had higher LRS than offspring from unmanipulated litters. We found no difference between the two experimental categories of offspring in adult weight, age at first reproduction, oxidative stress or telomere lengths. These findings are rare experimental evidence that prenatal and postnatal investments have distinct effects in moulding individual life history and fitness in wild mammals. This article is part of the theme issue 'Evolutionary ecology of inequality'.

Transcriptomic analysis supports a role for the nervous system in regulating growth and development of Fasciola hepatica juveniles

Fasciola spp. liver flukes have significant impacts in veterinary and human medicine. The absence of a vaccine and increasing anthelmintic resistance threaten sustainable control and underscore the need for novel flukicides. Functional genomic approaches underpinned by in vitro culture of juvenile Fasciola hepatica facilitate control target validation in the most pathogenic life stage. Comparative transcriptomics of in vitro and in vivo maintained 21 day old F. hepatica finds that 86% of genes are expressed at similar levels across maintenance treatments suggesting commonality in core biological functioning within these juveniles. Phenotypic comparisons revealed higher cell proliferation and growth rates in the in vivo juveniles compared to their in vitro counterparts. These phenotypic differences were consistent with the upregulation of neoblast-like stem cell and cell-cycle associated genes in in vivo maintained worms. The more rapid growth/development of in vivo juveniles was further evidenced by a switch in cathepsin protease expression profiles, dominated by cathepsin B in in vitro juveniles and by cathepsin L in in vivo juveniles. Coincident with more rapid growth/development was the marked downregulation of both classical and peptidergic neuronal signalling components in in vivo maintained juveniles, supporting a role for the nervous system in regulating liver fluke growth and development. Differences in the miRNA complements of in vivo and in vitro juveniles identified 31 differentially expressed miRNAs, including fhe-let-7a-5p, fhe-mir-124-3p and miRNAs predicted to target Wnt-signalling, which supports a key role for miRNAs in driving the growth/developmental differences in the in vitro and in vivo maintained juvenile liver fluke. Widespread differences in the expression of neuronal genes in juvenile fluke grown in vitro and in vivo expose significant interplay between neuronal signalling and the rate of growth/development, encouraging consideration of neuronal targets in efforts to dysregulate growth/development for parasite control.

O-042 ESHRE good practice recommendations on chromosomal mosaicism

The implementation of high-resolution genome-wide methods, usually next-generation sequencing-based, in preimplantation genetic testing (PGT), has led to the frequent detection of embryos with chromosomal mosaicism (whole chromosome and/or segmental aberrations). Despite a growing series of papers showing the birth of healthy babies following the transfer of embryos indicating mosaicism on PGT-A analysis - albeit with lower implantation rates and higher miscarriage rates in comparison with euploid embryo transfer - many questions remain, making it difficult to decide on how to handle chromosomally mosaic embryos in the clinic.

A dedicated ESHRE working group developed good practice recommendations on how to manage chromosomal mosaicism in clinical practice. The recommendations were formulated based on the expert opinion of the working group while taking into consideration the published data and outcomes of a survey on current practices in 239 PGT laboratories and ART clinics, mostly within Europe, Asia and America. The recommendations with regards to detection and management of chromosomal mosaicism were developed following the manual for development of ESHRE good practice recommendations with a stakeholder review of the paper on the ESHRE website. In addition to the recommendations, the working group identified missing information and scientific questions, which should guide further research in PGT, with relevance to the occurrence, detection and impact of chromosomal mosaicism.

Trial registration number:

Identifying and optimizing human endometrial gene expression signatures for endometrial dating

STUDY QUESTION

What are the key considerations for developing an enhanced transcriptomic method for secretory endometrial tissue dating?

SUMMARY ANSWER

Multiple gene expression signature combinations can serve as biomarkers for endometrial dating, but their predictive performance is variable and depends on the number and identity of the genes included in the prediction model, the dataset characteristics and the technology employed for measuring gene expression.

WHAT IS KNOWN ALREADY

Among the new generation of transcriptomic endometrial dating (TED) tools developed in the last decade, there exists variation in the technology used for measuring gene expression, the gene makeup and the prediction model design. A detailed study, comparing prediction performance across signatures for understanding signature behaviour and discrepancies in gene content between them, is lacking.

STUDY DESIGN, SIZE, DURATION

A multicentre prospective study was performed between July 2018 and October 2020 at five different centres from the same group of clinics (Spain). This study recruited 281 patients and finally included in the gene expression analysis 225 Caucasian patients who underwent IVF treatment. After preprocessing and batch effect filtering, gene expression measurements from 217 patients were combined with artificial intelligence algorithms (support vector machine, random forest and k-nearest neighbours) allowing evaluation of different prediction models. In addition, secretory-phase endometrial transcriptomes from gene expression omnibus (GEO) datasets were analysed for 137 women, to study the endometrial dating capacity of genes independently and grouped by signatures. This provided data on the consistency of prediction across different gene expression technologies and datasets.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometrial biopsies were analysed using a targeted TruSeq (Illumina) custom RNA expression panel called the endometrial dating panel (ED panel). This panel included 301 genes previously considered relevant for endometrial dating as well as new genes selected for their anticipated value in detecting the secretory phase. Final samples (n = 217) were divided into a training set for signature discovery and an independent testing set for evaluation of predictive performance of the new signature. In addition, secretory-phase endometrial transcriptomes from GEO were analysed for 137 women to study endometrial dating capacity of genes independently and grouped by signatures. Predictive performance among these signatures was compared according to signature gene set size.

MAIN RESULTS AND THE ROLE OF CHANCE

Testing of the ED panel allowed development of a model based on a new signature of 73 genes, which we termed 'TED' and delivers an enhanced tool for the consistent dating of the secretory phase progression, especially during the mid-secretory endometrium (3-8 days after progesterone (P) administration (P + 3-P + 8) in a hormone replacement therapy cycle). This new model showed the best predictive capacity in an independent test set for staging the endometrial tissue in the secretory phase, especially in the expected window of implantation (average of 114.5 ± 7.2 h of progesterone administered; range in our patient population of 82-172 h). Published sets of genes, in current use for endometrial dating and the new TED genes, were evaluated in parallel in whole-transcriptome datasets and in the ED panel dataset. TED signature performance was consistently excellent for all datasets assessed, frequently outperforming previously published sets of genes with a smaller number of genes for dating the endometrium in the secretory phase. Thus, this optimized set exhibited prediction consistency across datasets.

LARGE SCALE DATA

The data used in this study is partially available at GEO database. GEO identifiers GSE4888, GSE29981, GSE58144, GSE98386.

LIMITATIONS, REASONS FOR CAUTION

Although dating the endometrial biopsy is crucial for investigating endometrial progression and the receptivity process, further studies are needed to confirm whether or not endometrial dating methods in general are clinically useful and to guide the specific use of TED in the clinical setting.

WIDER IMPLICATIONS OF THE FINDINGS

Multiple gene signature combinations provide adequate endometrial dating, but their predictive performance depends on the identity of the genes included, the gene expression platform, the algorithms used and dataset characteristics. TED is a next-generation endometrial assessment tool based on gene expression for accurate endometrial progression dating especially during the mid-secretory.

STUDY FUNDING/COMPETING INTEREST(S)

Research funded by IVI Foundation (1810-FIVI-066-PD). P.D.-G. visiting scientist fellowship at Oxford University (BEFPI/2010/032) and Josefa Maria Sanchez-Reyes' predoctoral fellowship (ACIF/2018/072) were supported by a program from the Generalitat Valenciana funded by the Spanish government. A.D.-P. is supported by the FPU/15/01398 predoctoral fellowship from the Ministry of Science, Innovation and Universities (Spanish Government). D.W. received support from the NIHR Oxford Biomedical Research Centre. The authors do not have any competing interests to declare.

O-172 Metabolic imaging of cumulus cells to predict embryo implantation potential

Study question

Can non-invasive metabolic imaging detect variations in cumulus cell metabolic parameters associated with a viable pregnancy of the corresponding embryo?

Summary answer

Noninvasive metabolic imaging can detect differences in the cumulus cell metabolic signatures between embryos that led to a viable pregnancy and those that did not. 

What is known already

Bidirectional metabolic cooperativity between the human oocyte and its surrounding cumulus cells is essential for the oocyte to acquire full developmental competency. However, the relationship between cumulus cell metabolism and oocyte viability is not well established. Metabolic imaging uses Fluorescence Lifetime Imaging Microscopy (FLIM) to non-invasively measure autofluorescence of the endogenous molecules, NADH and FAD+, which are essential coenzymes for cellular respiration and glycolysis. This technique enables quantitative information for these coenzyme concentrations and regarding metabolite enzyme engagement. We have previously shown that this technique is an effective tool for quantitatively measuring metabolic state of mouse embryos.

Study design, size, duration

Cumulus cell clusters (n = 617 from 193 patients) were dissected from cumulus-oocyte complexes prior to insemination or ICSI, vitrified, warmed and their metabolic function assessed. We conducted a prospective observational study to evaluate to what extent cumulus cells from an oocyte that led to a viable pregnancy (presence of a viable fetus >7 weeks gestation) after transfer of the corresponding embryo metabolically differed from those that did not. We also evaluated the associations with embryo morphology.

Participants/materials, setting, methods

Cumulus cell metabolism was assessed non-invasively using FLIM to measure the autofluorescence of NADH and FAD+. Overall a single FLIM measurement provides a total of 8 metabolic parameters (4 for NADH and 4 for FAD+). An additional parameter, the Redox Ratio was also acquired (NADH intensity / FAD+ intensity). We used multilevel models to investigate the association of cumulus cell metabolic parameters with the morphology of the corresponding embryo and clinical outcome.

Main results and the role of chance

Of the cumulus samples analyzed, 75 corresponded to embryos that did not result in a viable pregnancy, and 24 that did so. Significant associations were observed between cumulus cell FAD+ fraction bound to enzyme (p = 0.007), FAD+ long lifetime (p = 0.01) and FAD+ short lifetime (p < 0.001) and the clinical outcome of the corresponding embryo. These significant associations held up after controlling for age. We used a support vector machine algorithm to distinguish between embryos that led to a viable pregnancy and those that did not. The optimum hyperplane derived from a support vector machine algorithm predicted whether a sample with random cumulus cell metabolic parameters will lead to a viable pregnancy or not with an accuracy of 80%. Embryo morphological assessments were stratified as excellent, good, fair and poor. We found no significant associations between cumulus cell metabolic signatures and embryo morphology evaluated on day 3. Significant associations of FAD+ short lifetime (p < 0.001) and day 5 embryo morphology were found. However, these associations were not significant after controlling for age. 

Limitations, reasons for caution

Although we observed significant variations in metabolic parameters, further studies with larger sample sizes are required. Despite our validation studies showing no significant effect of vitrification on cumulus cell metabolic parameters, analyses with fresh clusters are needed to confirm our results.

Wider implications of the findings

Noninvasive FLIM imaging detects metabolic variations of cumulus masses and their association with embryo viability. The ability to correlate metabolic measurements of cumulus clusters, in combination with embryo morphology assessments and patient clinical characteristics, with embryo fate paves the way for this approach to be used in a clinical setting.

Trial registration number

5RO1HD092559-03

Molecular characterisation and vaccine efficacy of two novel developmentally regulated surface tegument proteins of Fasciola hepatica

The surface tegument of Fasciola hepatica is a crucial tissue due to its key role at the host-parasite interface. We characterised three novel proteins, termed Fhteg1, Fhteg5 and Fhteg8, that are found in the tegument membrane fraction of adult F. hepatica. Bioinformatic analysis of proteomic datasets identified Fhteg5 and Fhteg8 as tegumental glycoproteins and revealed that Fhteg1, Fhteg5 and Fhteg8 are associated with exosomes of adult F. hepatica. Fhteg1, Fhteg5 and Fhteg8 appear to be related to uncharacterised sequences in F. gigantica, Fasciolopsis buski, Echinostoma caproni, Clonorchis sinensis, Opisthorchis viverrini, Schistosoma japonicum and S. mansoni, although F. hepatica appears to have expanded this family. Fhteg1 and Fhteg5 were characterised in detail. The Fhteg1 and Fhteg5 gene transcripts each demonstrate significant upregulation in juvenile fluke 2-4 days post-excystment, with transcript levels maintained during development over 3 weeks in vitro. RNAseq data showed that both Fhtegs are expressed in the adult life stage, although the transcript levels were about 8 fold lower than those in juveniles (3 week post infection). Using immunocytochemistry, Fhteg1 and Fhteg5 were each shown to be expressed in cells adjacent to the muscle layer as well as on the surface of 1 week old juveniles, whilst Fhteg5 was also present in cells at the base of the pharynx. RNAi mediated knockdown of Fhteg1 and Fhteg5 transcripts in 4-10 day old juveniles had no effect on parasite survival, movement or growth in vitro. Although no IgG responses were observed for Fhteg1 or Fhteg5 during infection in sheep and cattle, both proteins elicited a low IgG response in a proportion of infected rats. Rats vaccinated with Fhteg1 and Fhteg5 showed good IgG responses to both proteins and a mean 48.2 % reduction in worm burden following parasite challenge. Although vaccination of cattle with both proteins induced a range of IgG responses, no protection was observed against parasite challenge. This is the first study to provide insights into the molecular properties of two novel, developmentally regulated surface tegument proteins in F. hepatica.

A national quality improvement programme to improve survival after emergency abdominal surgery: the EPOCH stepped-wedge cluster RCT

Background

Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients.

Objectives

The objectives were to assess whether or not the QI programme improves 90-day survival after emergency abdominal surgery; to assess effects on 180-day survival, hospital stay and hospital readmission; and to better understand these findings through an integrated process evaluation, ethnographic study and cost-effectiveness analysis.

Design

This was a stepped-wedge cluster randomised trial. Hospitals were organised into 15 geographical clusters, and commenced the QI programme in random order over 85 weeks. Analyses were performed on an intention-to-treat basis. The primary outcome was analysed using a mixed-effects parametric survival model, adjusting for time-related effects. Ethnographic and economics data were collected in six hospitals. The process evaluation included all hospitals.

Setting

The trial was set in acute surgical services of 93 NHS hospitals.

Participants

Patients aged ≥ 40 years who were undergoing emergency abdominal surgery were eligible.

Intervention

The intervention was a QI programme to implement an evidence-based care pathway.

Main outcome measures

The primary outcome measure was mortality within 90 days of surgery. Secondary outcomes were mortality within 180 days, length of hospital stay and hospital readmission within 180 days. The main economic measure was the quality-adjusted life-years.

Data sources

Data were obtained from the National Emergency Laparotomy Audit database; qualitative interviews and ethnographic observations; quality-of-life and NHS resource use data were collected via questionnaires.

Results

Of 15,873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 participants in the usual care group and 7374 in the QI group. The primary outcome occurred in 1393 participants in the usual care group (16%), compared with 1210 patients in the QI group (16%) [QI vs. usual care hazard ratio (HR) 1.11, 95% confidence interval (CI) 0.96 to 1.28]. No differences were found in mortality at 180 days or hospital readmission; there was a small increase in hospital stay in the QI group (HR for discharge 0.90, 95% CI 0.83 to 0.97). There were only modest improvements in care processes following QI implementation. The ethnographic study revealed good QI engagement, but limited time and resources to implement change, affecting which processes teams addressed, the rate of change and eventual success. In some sites, there were challenges around prioritising the intervention in busy environments and in obtaining senior engagement. The intervention is unlikely to be cost-effective at standard cost-effectiveness thresholds, but may be cost-effective over the lifetime horizon.

Limitations

Substantial delays were encountered in securing data access to national registries. Fewer patients than expected underwent surgery and the mortality rate was lower than anticipated.

Conclusions

There was no survival benefit from a QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. The modest impact of the intervention on process measures, despite good clinician engagement, may have been limited by the time and resources needed to improve patient care.

Future work

Future QI programmes must balance intervention complexity with the practical realities of NHS services to ensure that such programmes can be delivered with the resources available.

Trial registration

Current Controlled Trials ISRCTN80682973 and The Lancet protocol 13PRT/7655.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 7, No. 32. See the NIHR Journals Library website for further project information.

Effectiveness of a national quality improvement programme to improve survival after emergency abdominal surgery (EPOCH): a stepped-wedge cluster-randomised trial

BACKGROUND

Emergency abdominal surgery is associated with poor patient outcomes. We studied the effectiveness of a national quality improvement (QI) programme to implement a care pathway to improve survival for these patients.

METHODS

We did a stepped-wedge cluster-randomised trial of patients aged 40 years or older undergoing emergency open major abdominal surgery. Eligible UK National Health Service (NHS) hospitals (those that had an emergency general surgical service, a substantial volume of emergency abdominal surgery cases, and contributed data to the National Emergency Laparotomy Audit) were organised into 15 geographical clusters and commenced the QI programme in a random order, based on a computer-generated random sequence, over an 85-week period with one geographical cluster commencing the intervention every 5 weeks from the second to the 16th time period. Patients were masked to the study group, but it was not possible to mask hospital staff or investigators. The primary outcome measure was mortality within 90 days of surgery. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN80682973.

FINDINGS

Treatment took place between March 3, 2014, and Oct 19, 2015. 22 754 patients were assessed for elegibility. Of 15 873 eligible patients from 93 NHS hospitals, primary outcome data were analysed for 8482 patients in the usual care group and 7374 in the QI group. Eight patients in the usual care group and nine patients in the QI group were not included in the analysis because of missing primary outcome data. The primary outcome of 90-day mortality occurred in 1210 (16%) patients in the QI group compared with 1393 (16%) patients in the usual care group (HR 1·11, 0·96-1·28).

INTERPRETATION

No survival benefit was observed from this QI programme to implement a care pathway for patients undergoing emergency abdominal surgery. Future QI programmes should ensure that teams have both the time and resources needed to improve patient care.

FUNDING

National Institute for Health Research Health Services and Delivery Research Programme.

Can research align with service? Lessons learned from the Big Experiment and National Biomechanics Day

Public engagement is an important role for the university academic, but is often neglected due to perceived lack of time and prioritized commitments in research and teaching. Yet, public engagement events offer an untapped opportunity for researchers to collect data from members of the general public who arrive on site at university labs. These engagement events could allow for data collection as part of didactic and demonstrative outreach events to be used in research and science. In this proof of concept study, a collaborative group of international researchers investigated the feasibility of embedding research quality assessment into events surrounding National Biomechanics Day. The Big Experiment collected data on 501 secondary school students (age range: 13 to 18 years) across 9 university sites within a 24-hour period. Data included maximal vertical jump height and self-reported physical activity levels. Vertical jump height was positively correlated to participant height, but not age or body mass. Very physically active students had significantly higher vertical jump heights than individuals who reported being somewhat or not physically active. This feasibility project demonstrates that with substantial preparation and a simple research design, focused research questions can be incorporated into educational outreach initiatives and ultimately provide a rich data source.

Rice plants overexpressing OsEPF1 show reduced stomatal density and increased root cortical aerenchyma formation

Stomata are adjustable pores in the aerial epidermis of plants. The role of stomata is usually described in terms of the trade-off between CO₂ uptake and water loss. Little consideration has been given to their interaction with below-ground development or diffusion of other gases. We overexpressed the rice EPIDERMAL PATTERNING FACTOR1 (OsEPF1) to produce rice plants with reduced stomatal densities, resulting in lowered leaf stomatal conductance and enhanced water use efficiency. Surprisingly, we found that root cortical aerenchyma (RCA) is formed constitutively in OsEPF1OE lines regardless of tissue age and position. Aerenchyma is tissue containing air-spaces that can develop in the plant root during stressful conditions, e.g. oxygen deficiency when it functions to increase O₂ diffusion from shoot to root. The relationship with stomata is unknown. We conclude that RCA development and stomatal development are linked by two possible mechanisms: first that reduced stomatal conductance inhibits the diffusion of oxygen to the root, creating an oxygen deficit and stimulating the formation of RCA, second that an unknown EPF signalling pathway may be involved. Our observations have fundamental implications for the understanding of whole plant gas diffusion and root-to-shoot signalling events.

183 Generation of porcine embryonic stem cell lines derived from nuclear transfer embryos reconstructed with induced pluripotent stem cells

To establish a porcine embryonic stem (ES) cell line that not only maintains self-renewing capacity but also exhibits pluripotency [Haraguchi et al. 2012 J. Reprod. Dev. 58, 707-716], 6 synthetic porcine RNAs (Oct4, Sox2, Klf4, c-Myc, Nanog, and Lin28) were chemically transfected into outgrowth cultured cells derived from the inner cell mass of in vitro-produced porcine embryos. Subsequently, cells grew as compact, dome-shaped colonies displaying alkaline phosphatase activity and were cultured for more than 20 passages. Although 13 candidate cell lines were generated (13/43, 30%), none formed teratomas after injection of the cells into SCID (sever combined immunodeficiency) mice. We also observed that when transfection of the exogeneous RNAs was discontinued, the cells no longer maintained a stem cell morphology and began to differentiate (13/13, 100%). This suggests that continuous expression of exogenous reprogramming factors is necessary to maintain induced pluripotency in the pig. Next, we used cloned embryos reconstructed with porcine induced pluripotent stem cells (piPSC), which were created using a recombinant lentivirus expression vector carrying 6 mouse reprogramming factor genes (the same as above) and green fluorescent protein (GFP) (Fukuda et al. 2017 J. Cell Biochem. 118, 537-553]. The piPSC were dispersed to a single cell suspension and electrically fused to cytoplasts prepared following enucleation of in vitro-matured zona-free metaphase II-arrested oocytes. A second cytoplast was then fused to the first reconstruct (double cytoplast nuclear transfer). Reconstructs were electrically activated and cultured in microwells with porcine zygote medium-3 (PZM3). After 5 days, reconstructed embryos developed to GFP-positive blastocysts (10/93, 11%) and 4- to 8-cell stages (25/93, 27%). The blastocysts (10) and 4- to 8-cell-stage embryos (25) were transferred onto mouse embryonic fibroblast feeder cells for outgrowth culture in FCS-based ES cell medium supplemented with 2% polyvinylpyrrolidone. After 24h, the medium was changed to piPSC medium containing CHIR99021, PD0325901, thiazovivin, and GF-109203x. Embryos attached to the feeder cells began to outgrow (8/10 of blastocysts and 6/25 of 4- to 8-cell-stage embryos). To date, 3 ES-like cell lines have been established from blastomeres of embryos (3/25, 12%) but not from blastocysts (0/10, 0%). They show GFP fluorescence and have been maintained continuously in culture for more than 20 passages without any overt changes in morphology. These results suggest that the constant expression of reprogramming factors and the use of combinations of specific small molecule inhibitors largely contribute to the establishment of pluripotent cells in the pig. Further characterisation of the cells is ongoing, including methylation status of the X chromosome and the capacity for in vivo differentiation.

Profiling G protein-coupled receptors of Fasciola hepatica identifies orphan rhodopsins unique to phylum Platyhelminthes

G protein-coupled receptors (GPCRs) are established drug targets. Despite their considerable appeal as targets for next-generation anthelmintics, poor understanding of their diversity and function in parasitic helminths has thwarted progress towards GPCR-targeted anti-parasite drugs. This study facilitates GPCR research in the liver fluke, Fasciola hepatica, by generating the first profile of GPCRs from the F. hepatica genome. Our dataset describes 147 high confidence GPCRs, representing the largest cohort of GPCRs, and the largest set of in silico ligand-receptor predictions, yet reported in any parasitic helminth. All GPCRs fall within the established GRAFS nomenclature; comprising three glutamate, 135 rhodopsin, two adhesion, five frizzled, one smoothened, and one secretin GPCR. Stringent annotation pipelines identified 18 highly diverged rhodopsins in F. hepatica that maintained core rhodopsin signatures, but lacked significant similarity with non-flatworm sequences, providing a new sub-group of potential flukicide targets. These facilitated identification of a larger cohort of 76 related sequences from available flatworm genomes, representing new members of existing groups (PROF1/Srfb, Rho-L, Rho-R, Srfa, Srfc) of flatworm-specific rhodopsins. These receptors imply flatworm specific GPCR functions, and/or co-evolution with unique flatworm ligands, and could facilitate the development of exquisitely selective anthelmintics. Ligand binding domain sequence conservation relative to deorphanised rhodopsins enabled high confidence ligand-receptor matching of seventeen receptors activated by acetylcholine, neuropeptide F/Y, octopamine or serotonin. RNA-Seq analyses showed expression of 101 GPCRs across various developmental stages, with the majority expressed most highly in the pathogenic intra-mammalian juvenile parasites. These data identify a broad complement of GPCRs in F. hepatica, including rhodopsins likely to have key functions in neuromuscular control and sensory perception, as well as frizzled and adhesion/secretin families implicated, in other species, in growth, development and reproduction. This catalogue of liver fluke GPCRs provides a platform for new avenues into our understanding of flatworm biology and anthelmintic discovery.

Mitochondrial DNA quantification as a tool for embryo viability assessment: retrospective analysis of data from single euploid blastocyst transfers

STUDY QUESTION

Does the amount of mitochondrial DNA (mtDNA) in blastocyst biopsy specimens have the potential to serve as a biomarker of euploid embryo implantation ability, independent of morphology?

SUMMARY ANSWER

The results of this study strongly suggest that elevated mtDNA levels, above a previously defined threshold, are strongly associated with blastocyst implantation failure and represent an independent biomarker of embryo viability.

WHAT IS KNOWN ALREADY

Improved methods of embryo selection are highly desirable in order to increase the efficiency of IVF treatment. At present, even the transfer of chromosomally normal embryos of high morphological grade cannot guarantee that a pregnancy will follow. Recently, it has been proposed that the quantity of mtDNA in embryonic cells may be an indicator of developmental potential, with higher levels of mtDNA associated with reduced implantation. However, thus far reported data sets have been relatively small and in some cases have lacked appropriate validation.

STUDY DESIGN, SIZE, DURATION

This large, blinded, retrospective study involved the analysis of relative mtDNA levels in 1505 euploid blastocysts obtained from 490 couples undergoing preimplantation genetic testing for aneuploidy. Implantation outcomes were compared to mtDNA levels in order to determine the capacity of the method to predict viability and to assess the validity of previously established thresholds.

PARTICIPANTS/MATERIALS, SETTING, METHODS

DNA from blastocyst biopsy samples was amplified and then subjected to aneuploidy analysis using next generation sequencing or array comparative genomic hybridization. Only those embryos classified as chromosomally normal had their mtDNA levels assessed. This analysis was undertaken retrospectively using quantitative real-time PCR, without knowledge of the outcome of embryo transfer. Predictions of implantation failure, based upon mtDNA levels were subsequently compared to the observed clinical results. All cycles involved the transfer of a single embryo.

MAIN RESULTS AND THE ROLE OF CHANCE

Of all blastocysts analyzed, 9.2% (139/1505) contained mtDNA levels above a previously established viability threshold and were therefore predicted to have reduced chances of implantation. To the date of analysis, 282 euploid blastocysts had been transferred with an overall implantation rate of 65.6% (185/282). Of the transferred embryos, 249 contained levels of mtDNA in the normal range, 185 of which produced a pregnancy, giving an implantation rate of 74.3% for euploid embryos with 'normal' quantities of mtDNA. However, 33 of the transferred embryos were determined to have elevated mtDNA quantities. None of these led to a pregnancy. Therefore, the negative predictive value of mtDNA assessment in this cohort was 100% (33/33). The difference between the implantation rates for embryos with normal and elevated mtDNA levels was highly significant (P < 0.0001). The mtDNA thresholds, used for classification of embryos, were unaffected by female age or the clinic in which the IVF was undertaken. The probability of an embryo having elevated levels of mtDNA was not influenced by variation in embryo morphology.

LIMITATIONS, REASONS FOR CAUTION

This study provides strong evidence that mtDNA quantification can serve as a valuable tool to assist the evaluation of blastocyst viability. However, to determine the true extent of any clinical benefits, other types of investigations, such as non-selection studies and randomized controlled trials, will also be necessary.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study suggest that mtDNA quantity can serve as an independent biomarker for the prediction of euploid blastocyst implantation potential. Prospective studies should now be undertaken to confirm these results. Additionally, investigations into the underlying biological cause(s) of elevated mtDNA levels and an enhanced understanding of how they relate to diminished implantation potential would be invaluable.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by funding provided by Reprogenetics. None of the authors have any competing interests.

Precise and Accurate Measurements of Strong-Field Photoionization and a Transferable Laser Intensity Calibration Standard

Ionization of atoms and molecules in strong laser fields is a fundamental process in many fields of research, especially in the emerging field of attosecond science. So far, demonstrably accurate data have only been acquired for atomic hydrogen (H), a species that is accessible to few investigators. Here, we present measurements of the ionization yield for argon, krypton, and xenon with percent-level accuracy, calibrated using H, in a laser regime widely used in attosecond science. We derive a transferable calibration standard for laser peak intensity, accurate to 1.3%, that is based on a simple reference curve. In addition, our measurements provide a much needed benchmark for testing models of ionization in noble-gas atoms, such as the widely employed single-active electron approximation.

Revisiting guidelines for integration of flow cytometry results in the WHO classification of myelodysplastic syndromes-proposal from the International/European LeukemiaNet Working Group for Flow Cytometry in MDS

Definite progress has been made in the exploration of myelodysplastic syndromes (MDS) by flow cytometry (FCM) since the publication of the World Health Organization 2008 classification of myeloid neoplasms. An international working party initiated within the European LeukemiaNet and extended to include members from Australia, Canada, Japan, Taiwan and the United States has, through several workshops, developed and subsequently published consensus recommendations. The latter deal with preanalytical precautions, and propose small and large panels, which allow evaluating immunophenotypic anomalies and calculating myelodysplasia scores. The current paper provides guidelines that strongly recommend the integration of FCM data with other diagnostic tools in the diagnostic work-up of MDS.

Health outcomes of children born after IVF/ICSI: a review of current expert opinion and literature

The Sixth Evian Annual Reproduction (EVAR) Workshop Group Meeting was held to evaluate the impact of IVF/intracytoplasmic sperm injection on the health of assisted-conception children. Epidemiologists, reproductive endocrinologists, embryologists and geneticists presented data from published literature and ongoing research on the incidence of genetic and epigenetic abnormalities and congenital malformations in assisted-conception versus naturally conceived children to reach a consensus on the reasons for potential differences in outcomes between these two groups. IVF-conceived children have lower birthweights and higher peripheral fat, blood pressure and fasting glucose concentrations than controls. Growth, development and cognitive function in assisted-conception children are similar to controls. The absolute risk of imprinting disorders after assisted reproduction is less than 1%. A direct link between assisted reproduction and health-related outcomes in assisted-conception children could not be established. Women undergoing assisted reproduction are often older, increasing the chances of obtaining abnormal gametes that may cause deviations in outcomes between assisted-conception and naturally conceived children. However, after taking into account these factors, it is not clear to what extent poorer outcomes are due to the assisted reproduction procedures themselves. Large-scale, multicentre, prospective epidemiological studies are needed to investigate this further and to confirm long-term health consequences in assisted-conception children. Assisted reproduction treatment is a general term used to describe methods of achieving pregnancy by artificial means and includes IVF and sperm implantation. The effect of assisted reproduction treatment on the health of children born using these artificial methods is not fully understood. In April 2011, fertility research experts met to give presentations based on research in this area and to look carefully at the evidence for the effects of assisted reproduction treatment on children's health. The purpose of this review was to reach an agreement on whether there are differences in the health of assisted-conception children with naturally conceived children. The researchers discovered no increased risk in birth defects in assisted-conception children compared with naturally conceived children. They found that IVF-conceived children have lower birth weights and higher fat under the skin, higher blood pressure and higher fasting glucose concentrations than naturally conceived children; however, growth, development and cognitive function are similar between groups. A very low risk of disorders of genetic control was observed in assisted-conception children. Overall, there did not appear to be a direct link between assisted reproduction treatment and children's health. The researchers concluded that the cause of some differences in the health of children conceived using assisted reproduction treatment may be due to the age of the woman receiving treatment. Large-scale, research studies are needed to study the long-term health of children conceived using assisted reproduction treatment.