IVF culture media: past, present and future

Improved detection of mineral oil toxicity using an extended mouse embryo assay

PURPOSE

Successful in vitro fertilization (IVF) relies on sound laboratory methods and culture conditions which depend on sensitive quality control (QC) testing. This study aimed to improve the sensitivity of mouse embryo assays (MEA) for detection of mineral oil toxicity.

METHODS

Five experiments were conducted to study modifications of the standard mouse embryo assay (MEA) in order to improve sensitivity using clinical grade mineral oil with known peroxide concentrations. Assessment of blastocyst development at either 96 h or in an extended MEA (eMEA) to 144 h was tested in each experiment. In experiment 1, ability to detect peroxides in oil was compared in the MEA, eMEA, and cell number at 96 h. In experiment 2, serial dilutions of peroxide in oil were used along with time-lapse imaging to compare sensitivity of the morphokinetic MEA to the eMEA. Culture conditions that may affect assay sensitivity were assessed in experiments 3-5, which examined the effect of group versus individual culture, oxygen concentration, and protein supplementation.

RESULTS

Extended MEA and cell counts identified toxicity not detected by the routine endpoint of blastocyst rate at 96 h. The eMEA was fourfold more sensitive than the standard MEA, and this sensitivity was similar to the morphokinetic MEA. Group culture had a protective effect against toxicity, while oxygen concentration did not affect blastocyst development. Protein supplementation with HSA had a protective effect on blastocyst development in eMEA.

CONCLUSIONS

The standard MEA used by manufacturers does not detect potentially lethal toxicity of peroxides in mineral oil. While group culture may mask toxicity, protein supplementation and oxygen concentration have minimal effect on assay sensitivity. The eMEA and time-lapse morphokinetic assessment are equally effective in detection of peroxide toxicity and thus provide manufacturers and end-users a simple process modification that can be readily adopted into an existing QC program.

Common and specific transcriptional signatures in mouse embryos and adult tissues induced by in vitro procedures

Stressful environmental exposures incurred early in development can affect postnatal metabolic health and susceptibility to non-communicable diseases in adulthood, although the molecular mechanisms by which this occurs have yet to be elucidated. Here we use a mouse model to investigate how assorted in vitro exposures restricted exclusively to the preimplantation period affect transcription both acutely in embryos and long-term in subsequent offspring adult tissues, to determine if reliable transcriptional markers of in vitro stress are present at specific developmental time points and throughout development. Each in vitro fertilization or embryo culture environment led to a specific and unique blastocyst transcriptional profile, but we identified a common 18-gene and 9-pathway signature of preimplantation embryo manipulation that was present in all in vitro embryos irrespective of culture condition or method of fertilization. This fingerprint did not persist throughout development and there was no clear transcriptional cohesion between adult IVF offspring tissues or compared to their preceding embryos, indicating a tissue-specific impact of in vitro stress on gene expression. However, the transcriptional changes present in each IVF tissue were targeted by the same upstream transcriptional regulators, which provide insight as to how acute transcriptional responses to stressful environmental exposures might be preserved throughout development to influence adult gene expression.

Time to take human embryo culture seriously

STUDY QUESTION

Is it important that end-users know the composition of human embryo culture media?

SUMMARY ANSWER

We argue that there is as strong case for full transparency concerning the composition of embryo culture media intended for human use.

WHAT IS KNOWN ALREADY

Published data suggest that the composition of embryo culture media may influence the phenotype of the offspring.

STUDY DESIGN, SIZE, DURATION

A review of the literature was carried out.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data concerning the potential effects on embryo development of culture media were assessed and recommendations for users made.

MAIN RESULTS AND THE ROLE OF CHANCE

The safety of ART procedures, especially with respect to the health of the offspring, is of major importance. There are reports from the literature indicating a possible effect of culture conditions, including culture media, on embryo and fetal development. Since the introduction of commercially available culture media, there has been a rapid development of different formulations, often not fully documented, disclosed or justified. There is now evidence that the environment the early embryo is exposed to can cause reprogramming of embryonic growth leading to alterations in fetal growth trajectory, birthweight, childhood growth and long-term disease including Type II diabetes and cardiovascular problems. The mechanism for this is likely to be epigenetic changes during the preimplantation period of development. In the present paper the ESHRE working group on culture media summarizes the present knowledge of potential effects on embryo development related to culture media, and makes recommendations.

LIMITATIONS, REASONS FOR CAUTION

There is still a need for large prospective randomized trials to further elucidate the link between the composition of embryo culture media used and the phenotype of the offspring. We do not presently know if the phenotypic changes induced by in vitro embryo culture represent a problem for long-term health of the offspring.

WIDER IMPLICATIONS OF THE FINDINGS

Published data indicate that there is a strong case for demanding full transparency concerning the compositions of and the scientific rationale behind the composition of embryo culture media.

STUDY FUNDING/COMPETING INTERESTS

This work was funded by The European Society for Human Reproduction and Embryology. No competing interests to declare.

A descriptive study of culture media in Brazilian assisted reproduction clinics

Objective

The present study aimed to draw a profile of the most commonly used media and protocol characteristics from assisted reproduction technology (ART) facilities in Brazil.

Methods

To obtain an overview of ART methods and culture media, a questionnaire was given to embryologists from ART clinics in Brazil. Further research in scientific papers and journals was carried out for describing the processes around Brazil, USA and Europe.

Results

From the questionnaire, we found that the embryo medium mostly used is CSCM^TM from Irvine Scientific, represented 37.04% in Brazilian ART clinics; interestingly, 70.37% of clinics exchange the embryo media bath; however, 70.37% do not change the media type. Transfers in Brazilian clinics were variable, but day 3 transfer was a procedure seen in 37.04%. The remaining embryos are habitually maintained in prolonged cultivation in 51.85% of the clinics interviewed.

Conclusion

Although there are numerous studies trying to better understand embryo culture media influences, there is a lack of evidence for choosing one as the most appropriate. In short, it is a random decision for such an essential stage of In Vitro Fertilization.

The oviductal transcriptome is influenced by a local ovarian effect in the sow

BACKGROUND

Oviducts participate in fertilization and early embryo development, and they are influenced by systemic and local circulation. Local functional interplay between ovary, oviduct and uterus is important, as deduced from the previously observed differences in hormone concentrations, presence of sperm, or patterns of motility in the oviduct after unilateral ovariectomy (UO). However, the consequences of unilateral ovariectomy on the oviductal transcriptome remain unexplored. In this study, we have investigated the consequences of UO in a higher animal model as the pig.

METHODS

The influence of UO was analyzed on the number of ovulations on the contra ovary, which was increased, and on the ipsilateral oviductal transcriptome. Microarray analysis was performed and the results were validated by PCR. Differentially expressed genes (DEGs) with a fold change ≥ 2 and a false discovery rate of 10 % were analyzed by Ingenuity Pathway Analysis (IPA) to identify the main biofunctions affected by UO.

RESULTS

Data revealed two principal effects in the ipsilateral oviduct after UO: i) down-regulation of genes involved in the survival of sperm in the oviduct and early embryonic development, and ii) up-regulation of genes involved in others functions as protection against external agents and tumors.

CONCLUSIONS

Results showed that unilateral ovariectomy results in an increased number of ovulation points on the contra ovary and changes in the transcriptome of the ipsilateral oviduct with consequences on key biological process that could affect fertility output.

It is what it eats: Chemically defined media and the history of surrounds

The cultivation of living organs, cells, animals, and embryos in the laboratory has been central to the production of biological knowledge. Over the twentieth century, the drive to variance control in the experimental setting led to systematic efforts to generate synthetic, chemically defined substitutes for complex natural foods, housing, and other substrates of life. This article takes up the history of chemically defined media with three aims in mind. First, to characterize patterns of decontextualization, tinkering, and negotiation between life and experimenter that occur across disparate histories of cultivation. Second, to highlight the paradoxical historicity of cultivated organisms generated to be freed from context, as they incorporate and embody the purified amino acids, vitamins, plastics, and other artificial supports developed in the name of experimental control. Third, to highlight the figure-ground reversal that occurs as these cells and organisms are reconsidered as accidentally good models of life in industrialized conditions of pollution and nutrient excess, due to the man-made nature of their surrounds. Methodologically, the history of surrounds is described as an epigenetic approach that focuses on the material relations between different objects and organisms previously considered quite separately, from explanted organs to bacteria to plant cells to rats to human embryos.

Human Embryonic Stem Cell Lines with Lesions in FOXP3 and NF1

Human embryonic stem cells (hESCs) are derived from the inner cell mass (ICM) of blastocyst staged embryos. Spare blastocyst staged embryos were obtained by in vitro fertilization (IVF) and donated for research purposes. hESCs carrying specific mutations can be used as a powerful cell system in modeling human genetic disorders. We obtained preimplantation genetic diagnosed (PGD) blastocyst staged embryos with genetic mutations that cause human disorders and derived hESCs from these embryos. We applied laser assisted micromanipulation to isolate the inner cell mass from the blastocysts and plated the ICM onto the mouse embryonic fibroblast cells. Two hESC lines with lesions in FOXP3 and NF1 were established. Both lines maintain a typical undifferentiated hESCs phenotype and present a normal karyotype. The two lines express a panel of pluripotency markers and have the potential to differentiate to the three germ layers in vitro and in vivo. The hESC lines with lesions in FOXP3 and NF1 are available for the scientific community and may serve as an important resource for research into these disease states.

Effects of granulocyte-macrophage colony-stimulating factor supplementation in culture medium on embryo quality and pregnancy outcome of women aged over 35 years

PURPOSE

The purpose of this study is to explore whether a low concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF) supplementation in culture medium is beneficial to infertile women aged over 35 years.

METHODS

A retrospective cohort study was performed to analyze the embryo quality and pregnancy outcome of 212 controlled ovarian stimulation (COH) cycles with or without GM-CSF addition (n = 117 [GM-CSF, 0.2 ng/mL] vs n = 95 [control]).

RESULTS

No significant difference was observed in cleavage rate (96.2 vs 96.5 %), blastocyst formation rate (53.2 vs 54.0 %), good blastocyst rate (26.8 vs 26.8 %), or available embryo rate (54.2 vs 49.7 %) between the GM-CSF group and the control group. However, the average age of the GM-CSF group (38.41 ± 3.13 years) was significantly 1 year older than that of the corresponding control group (37.45 ± 2.74 years) (P < 0.05). GM-CSF addition greatly decreased the occurrence of biochemical pregnancy (55.6 % [control] vs 20.8 % [GM-CSF], P < 0.05). No case of neonatal malformation was observed in the present study.

CONCLUSION

Although no benefit of GM-CSF on embryo quality was observed, the addition of this factor significantly decreased the occurrence of chemical pregnancy of women aged over 35 years, indicating the role of GM-CSF in improving implantation competence of embryos derived from elderly infertile women.

Endometrial pattern, but not endometrial thickness, affects implantation rates in euploid embryo transfers

OBJECTIVE

To evaluate the relationship of endometrial thickness (EnT) and endometrial pattern (EnP) to euploid embryo transfer (ET) outcomes.

DESIGN

Retrospective cohort.

SETTING

Private academic clinic.

PATIENT(S)

Patients (n = 277; age 36.1 ± 4.0 years) whose embryos (n = 476) underwent aneuploidy screening with fresh (n = 176) or frozen (n = 180) ET from July 2010 to March 2014.

INTERVENTION(S)

The EnT and EnP were measured on trigger day and at ET. Patients were stratified by age and cycle type (fresh or frozen). Cycle data were combined at trigger day, but separated at ET day.

MAIN OUTCOME MEASURE(S)

Outcome measures were implantation rate, pregnancy rate, and clinical pregnancy rate. Analysis was conducted using χ(2) analysis and Fisher's exact test.

RESULT(S)

A total of 234 gestational sacs, 251 pregnancies, and 202 clinical pregnancies resulted from 356 cycles. The EnT (9.6 ± 1.8 mm; range: 5-15 mm) at trigger day (n = 241 cycles), as a continuous or categorical variable (≤8 vs. >8 mm), was not associated with implantation rate, pregnancy rate, or clinical pregnancy rate. The EnT at day of fresh ET (9.7 ± 2.2 mm; range: 4.4-17.9 mm) (n = 176 cycles) or frozen ET (9.1 ± 2.1 mm; range: 4.2-17.7 mm) (n = 180 cycles) was not associated with implantation rate, pregnancy rate, or clinical pregnancy rate. Type 3 EnP at trigger day was associated with increased serum progesterone at trigger and a decreased implantation rate, compared with type 2 EnP. The EnP at fresh or frozen ET was not associated with implantation rate, pregnancy rate, or clinical pregnancy rate.

CONCLUSION(S)

Within the study population, EnT was not significantly associated with clinical outcomes of euploid ETs. A type 3 EnP at trigger day suggests a prematurely closed window of implantation.

A critical appraisal of time-lapse imaging for embryo selection: where are we and where do we need to go?

PURPOSE

The aim of this study was to undertake a critical appraisal of the available evidence for the use of time-lapse imaging for embryo selection in clinical IVF.

METHODS

A literature search in PubMed, Scopus, Cochrane Central, ClinicalTrials.gov, Current Controlled Trials, and WHO International Clinical Trials Registry Platform was performed to identify randomized controlled trials that investigated the effect of time-lapse embryo selection and/or the time-lapse incubation system on ongoing pregnancy rate. We then performed a systematic review and assessed the relative risks (RRs) and 95 % confidence intervals (CIs) for ongoing pregnancy rates and the risk of bias of the eligible studies.

RESULTS

We identified four eligible randomized studies, three of which investigated the effect of both time-lapse incubation system and selection on ongoing pregnancy rate; the pooled result revealed a benefit of this intervention (relative risk (RR) 1.20; 95 % CI 1.05-1.37). However, the evidence was judged to be of low quality due to study limitations; a beneficial effect was observed in only one study deemed to be at high risk of bias. The single study assessing the effect of only the time-lapse incubation system revealed a non-significant negative effect (RR 0.71; 95 % CI 0.49-1.03).

CONCLUSIONS

The findings from this systematic review of the current evidence do not support routine use of time-lapse technology in clinical IVF. We therefore believe that the use of time-lapse imaging for embryo selection should remain experimental and that couples should not be subject to a surcharge for having their embryos cultured in a time-lapse imaging system. Future studies evaluating this technology in well-designed trials should be performed.

Does the type of culture medium used influence birthweight of children born after IVF?

STUDY QUESTION

Do culture media influence birthweight of children born after IVF?

SUMMARY ANSWER

Some studies have observed a significant effect of culture media on birthweight, while others have not, but since most studies compared different culture media, conventional meta-analysis was not possible.

WHAT IS KNOWN ALREADY

Animal studies suggest that in vitro culture of embryos can have a significant effect on the birthweight of offspring when compared with in vivo developed embryos. The type of culture medium (or certain components of the medium) used is one of the causal factors.

STUDY DESIGN, SIZE, DURATION

We reviewed all available literature reporting on a relation between culture medium and birthweight in human studies and a selection of animal studies.

PARTICIPANTS/MATERIALS, SETTING, METHODS

An extensive literature search on Pubmed and Medline was performed with relevant search criteria relating to IVF, birthweight and culture medium.

MAIN RESULTS AND THE ROLE OF CHANCE

Eleven studies reporting on a relationship between culture medium and birthweight in human were included in this review. Five of these found significant differences in birthweight when offspring born after culture in different culture media were compared. The remaining studies did not find differences in birthweight after changing culture medium.

LIMITATIONS, REASONS FOR CAUTION

The number of human studies is limited and different culture media with different compositions are compared which makes a comparison between the studies difficult, if not impossible. Furthermore, most study designs were retrospective with consecutive use of different culture media and limited sample sizes, which makes bias of the results likely.

WIDER IMPLICATIONS OF THE FINDINGS

If it could be confirmed that the type of culture medium used does indeed influence phenotypic characteristics (such as birthweight) of children born after IVF, it would underline the importance of monitoring the health of IVF children in relation to aspects of the laboratory techniques used during embryo culture.

STUDY FUNDING/COMPETING INTERESTS

No funding was applicable to this study. No conflict of interest is declared.