Granulocyte-macrophage colony stimulating factor (GM-CSF) and co-culture can affect post-thaw development and apoptosis in cryopreserved embryos

Granulocyte-Macrophage Colony-Stimulating Factor Cytokine Addition After the Freeze-Thawing Process Improves Human Sperm Motility and Vitality in Asthenoteratozoospermia Patients

The cryopreservation-thawing process of spermatozoa cells has negative impacts on their structure, function, and fertility parameters, which are known as cryoinjury. Asthenozoospermia patients are more susceptible to cryoinjury. Granulocyte-macrophage colony-stimulating factor (GM-CSF) increases sperm glucose uptake via the induction of glucose transporters, resulting in increased sperm motility. This study aimed to investigate the efficiency of GM-CSF supplementation of the cryopreservation media for semen samples of asthenoteratozoospermia patients. The study was carried out on 20 semen samples from infertile men referred to diagnosing semen analysis. To avoid subjective bias, two main sperm motility parameters, including velocity along the curvilinear path and velocity along the straight-line path were considered by the computer-assisted sperm analysis system. Afterward, each semen sample was divided into three equal aliquots and randomly assigned to one of the following groups: group I (control, freezing media only), group II (+GM-CSF, freezing medium supplemented with 2 μL/mL GM-CSF), or group III (GM-CSF added after thawing and washing). Following semen thawing, standard parameters, mitochondrial membrane potential (MMP), and the DNA Fragmentation Index were analyzed. Total sperm motility (progressive and non-progressive) improved significantly in group III samples after a 30-minute incubation with GM-CSF compared with the control group (26.5% ± 3.1% vs. 17.51% ± 2.59%). However, no differences in progressive motility or sperm morphology were found among the three thawed samples. The percentage of vitality was significantly higher in group III compared with the other two groups (28.38% ± 3.4% vs. 22.4% ± 3.08% and 22.14% ± 2.77%, respectively) (p < 0.05). JC-1 levels (a marker of MMP) were not significantly different between the examined groups (44.95% ± 8.26% vs. 36.61% ± 6.95% vs. 46.67% ± 7.7%, for control, group II, and group III, respectively) (p > 0.05). GM-CSF may be advantageous as an additive after freezing, improving total motility and viability after 30 minutes of post-thaw incubation; however, when supplied to the freezing media before cryopreservation, it is unable to protect against cryoinjury.

Effects of Melatonin, GM-CSF, IGF-1, and LIF in Culture Media on Embryonic Development: Potential Benefits of Individualization

The implantation of good-quality embryos to the receptive endometrium is essential for successful live birth through in vitro fertilization (IVF). The higher the quality of embryos, the higher the live birth rate per cycle, and so efforts have been made to obtain as many high-quality embryos as possible after fertilization. In addition to an effective controlled ovarian stimulation process to obtain high-quality embryos, the composition of the embryo culture medium in direct contact with embryos in vitro is also important. During embryonic development, under the control of female sex hormones, the fallopian tubes and endometrium create a microenvironment that supplies the nutrients and substances necessary for embryos at each stage. During this process, the development of the embryo is finely regulated by signaling molecules, such as growth factors and cytokines secreted from the epithelial cells of the fallopian tube and uterine endometrium. The development of embryo culture media has continued since the first successful human birth through IVF in 1978. However, there are still limitations to mimicking a microenvironment similar to the reproductive organs of women suitable for embryo development in vitro. Efforts have been made to overcome the harsh in vitro culture environment and obtain high-quality embryos by adding various supplements, such as antioxidants and growth factors, to the embryo culture medium. Recently, there has been an increase in the number of studies on the effect of supplementation in different clinical situations such as old age, recurrent implantation failure (RIF), and unexplained infertility; in addition, anticipation of the potential benefits from individuation is rising. This article reviews the effects of representative supplements in culture media on embryo development.

Granulocyte-Macrophage Colony Stimulating Factor in Single Blastocyst Conditioned Medium as a Biomarker for Predicting Implantation Outcome of Embryo

Background

It is highly desirable to develop new strategies based on secretomics to more accurately selection of embryos with the highest developmental potential for transfer. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been reported to promote embryo development and pregnancy establishment. However, the predictive value of GM-CSF in single blastocyst selection remains unclear. This study is to determine the concentration of GM-CSF in human single-blastocyst conditioned medium (SBCM) and to evaluate its association with embryo quality and pregnancy outcome.

Methods

The patients with ≤38 years of age receiving the first cycle of assisted reproductive therapy were included in this study. The patients who had <4 top-quality embryos formed by the fertilized two pronuclear zygotes on day 3 were excluded. A total of 126 SBCM samples (SBCMs) were included, of which blastocysts from 77 SBCMs were later transferred in subsequent frozen-thawed embryo transfer. The concentrations of GM-CSF were detected by single-molecule array (SIMOA) and analyzed for their possible association with embryo quality and pregnancy outcomes. The top-quality embryo (TQ), positive HCG (HP), clinical pregnancy (CP), and ongoing pregnancy (OP) rates were determined and compared between groups divided based on GM-CSF concentrations.

Results

The detection rate of GM-CSF was found to be 50% in all SBCMs. There were significant differences in TQ rate, HP rate, CP rate and OP rate among high concentration group, medium concentration group and low concentration group. Both GM-CSF alone or GM-CSF combined with the morphological score (MS) had a greater AUC of ROC curve than that of MS alone to predict the pregnancy outcome, and GM-CSF combined with MS had the highest AUC.

Conclusions

The concentration of GM-CSF in SBCM was detected at fg/ml levels, which was associated with embryo quality and pregnancy outcome. Collectively, GM-CSF may be used as a biomarker for prediction of pregnancy outcome and selection of embryos with high developmental potential for transfer in assisted reproductive technology (ART).

IGF-I Medium Supplementation Improves Singly Cultured Cat Oocyte Maturation and Embryo Development In Vitro

Embryo production is a routine procedure in several species. However, in felids, the effectiveness of this approach is far behind that in the majority of laboratory species. The development of a suitable environment starts with the proper composition of culture media. Therefore, for the improvement of assisted reproduction techniques and their outcome in cats, this is an urgent task. As the addition of insulin-like growth factors (IGF-I, IGF-II) or granulocyte-macrophage colony-stimulating factor (GM-CSF) was beneficial in other mammalian species, this study aims to check whether these components, combined with other factors (such as type of fertilisation or type of culture) can provide a benefit in the felid culture system in current use. Thus, these supplements, in different concentrations and combinations, were merged with the use of two fertilisation techniques and randomly assigned to single or group culturing. The results showed that the addition of IGF-I and/or GM-CSF produced an increase in morula and blastocyst rate in a single culture system. In particular, the supplementation with 20 ng/mL of IGF-I incremented the maturation rate by 10% and significantly increased the morula and blastocyst rates in single culturing. This result is especially remarkable for wild felids, where only a few oocytes and/or embryos are available.

Different co-culture systems have the same impact on bovine embryo transcriptome

During the last few years, several co-culture systems using either BOEC or VERO feeder cells have been developed to improve bovine embryo development and these systems give better results at high oxygen concentration (20%). In parallel, the SOF medium, used at 5% O2, has been developed to mimic the oviduct fluid. Since 2010s, the SOF medium has become popular in improving bovine embryo development and authors have started to associate this medium to co-culture systems. Nevertheless, little is known about the putative benefit of this association on early development. To address this question, we have compared embryo transcriptomes in four different culture conditions: SOF with BOEC or VERO at 20% O2, and SOF without feeders at 5% or 20% O2. Embryos have been analyzed at 16-cell and blastocyst stages. Co-culture systems did not improve the developmental rate when compared to 5% O2. Direct comparison of the two co-culture systems failed to highlight major differences in embryo transcriptome at both developmental stages. Both feeder cell types appear to regulate the same cytokines and growth factors pathways, and thus to influence embryo physiology in the same way. In blastocysts, when compared to culture in SOF at 5% O2, BOEC or VERO seems to reduce cell survival and differentiation by, at least, negatively regulating STAT3 and STAT5 pathways. Collectively, in SOF medium both blastocysts rate and embryo transcriptome suggest no influence of feeder origin on bovine early development and no beneficial impact of co-culture systems when compared to 5% O2.

Sex and the preimplantation embryo: implications of sexual dimorphism in the preimplantation period for maternal programming of embryonic development

The developmental program of the embryo displays a plasticity that can result in long-acting effects that extend into postnatal life. In mammals, adult phenotype can be altered by changes in the maternal environment during the preimplantation period. One characteristic of developmental programming during this time is that the change in adult phenotype is often different for female offspring than for male offspring. In this paper, we propose the hypothesis that sexual dimorphism in preimplantation programming is mediated, at least in part, by sex-specific responses of embryos to maternal regulatory molecules whose secretion is dependent on the maternal environment. The strongest evidence for this idea comes from the study of colony-stimulating factor 2 (CSF2). Expression of CSF2 from the oviduct and endometrium is modified by environmental factors of the mother, in particular seminal plasma and obesity. Additionally, CSF2 alters several properties of the preimplantation embryo and has been shown to alleviate negative consequences of culture of mouse embryos on postnatal phenotype in a sex-dependent manner. In cattle, exposure of preimplantation bovine embryos to CSF2 causes sex-specific changes in gene expression, interferon-τ secretion and DNA methylation later in pregnancy (day 15 of gestation). It is likely that several embryokines can alter postnatal phenotype through actions directed towards the preimplantation embryo. Identification of these molecules and elucidation of the mechanisms by which sexually-disparate programming is established will lead to new insights into the control and manipulation of embryonic development.

Cryopreservation and In Vitro culture of Preimplantation Embryos in Djungarian Hamster (Phodopus sungorus)

Although embryo cryobanking was applied to Syrian golden and to Campbell's hamsters, no attempt has been made at freezing embryos in Djungarian hamsters. Four-cell stage embryos were flushed from the reproductive ducts of pregnant females before noon of the third-day post coitum and frozen in 0.25-ml straws according to standard procedures of slow cooling. A mixture of permeating (ethylene glycol) and non-permeating (sucrose) cryoprotectants was used. The thawing was performed by incubating at RT for 40 s followed by 40 s in a water bath at 30.0°C. Most (66.7%) of the non-frozen four-cell embryos developed up to the morula stage in rat one-cell embryo culture medium (R1ECM). The use of hamster embryo culture medium (HECM) yielded fewer morulas (18.2%) during the same 24-h period of culture. The rate of embryo's surviving the freezing-thawing procedures, as estimated by light microscopy, was 60.7-68.8%. After 24-h culturing in R1ECM, 64.7% of frozen-thawed four-cell embryos developed and all of them reached the morula stage. Supplementation of R1ECM with GM-CSF (2 ng/ml) improved the rate of Djungarian hamster frozen-thawed embryo development: 100% of the four-cell stage embryos developed, 50% of them achieved the morula stage, and 50% developed even further and reached the blastocyst stage within 24 h of culturing. This study reports the world's first successful transfer of frozen-thawed Djungarian hamster embryos yielding term pups. Taken together, the results of this study demonstrate the possibility of applying some key reproductive technologies, that is, embryo freezing/cryopreservation and in vitro culture, to Djungarian hamsters.

Dose-dependent embryotrophic effect of recombinant granulocyte-macrophage colony-stimulating factor and brain-derived neurotrophic factor in culture medium for mouse preimplantation embryo

OBJECTIVE

To evaluate the dose effect of recombinant mouse granulocyte-macrophage colony-stimulating factor (rmGM-CSF) or brain-derived neurotrophic factor (BDNF) in culture medium on the development of in vitro fertilized mouse embryos.

METHODS

Mature oocytes were retrieved from superovulated female BDF1 mice and inseminated by sperm from male BDF1 mice. On day 1, two-cell stage embryos were divided and cultured until day 5 in the embryo maintenance medium supplemented with 0, 1, 2, 5, or 10 ng/mL of rmGM-CSF or supplemented with 0, 5, 10, or 20 ng/mL of BDNF. Blastocyst formation rate and their cell numbers were assessed.

RESULTS

The blastocyst formation rate and the total cell count in blastocyst was similar in all the rmGM-CSF treatment groups when compared with the control. However, the blastocyst formation rate and the total cell count was significantly higher in the group supplemented with 10 ng/mL of BDNF compared with the control (63.9%, 45.8±11.5 vs. 52.3%, 38.0±6.8; P<0.05, respectively).

CONCLUSION

Supplementation of 10 ng/mL of BDNF enhanced the developmental potential of mouse preimplantation embryos, but supplementation of rmGM-CSF did not.

The effect of GM-CSF on development and aneuploidy in murine blastocysts

BACKGROUND

Growth factors and cytokines are present in small quantities in the oviduct and uterus and some are synthesized by the growing embryo. Granulocytes-macrophage colony-stimulating factor (GM-CSF) is known as an important regulator, which enhances cell proliferation and reduces apoptosis in developing blastocysts, during normal fetal and placental development. The purpose of this study is to investigate whether adding GM-CSF to the culture media affects blastulation or the chromosomal status of mouse embryos.

METHODS

Murine embryos were cultured in vitro from the 2-cell stage until the blastocyst stage in the presence of different concentrations of GM-CSF of 0 ng/ml (control), 1, 2, 5 and 10 ng/ml. The development of each embryo was noted and the embryos were then spread for fluorescence in situ hybridization (FISH) using locus-specific probes (LSI) for chromosomes 2, 11 and 16 in all embryos.

RESULTS

No difference in the blastulation potential was noted with the addition of 1 and 2 ng/ml of GM-CSF compared with the controls, but there was a significant decrease (P < 0.001) in the blastulation rate in the 5 and 10 ng/ml concentrations. The rate of mosaicism/aneuploidy noted in all GM-CSF groups (1, 2, 5 and 10 ng/ml) was slightly higher than in the control group (0 ng/ml GM-CSF) but the differences were not significant. In the mosaic embryos from the GM-CSF cultured groups, the percentage of aneuploid cells was statistically higher than in the control group.

CONCLUSIONS

GM-CSF exerted a negative impact on blastocyst development at higher concentrations. GM-CSF did not affect the rates of mosaicism/aneuploidy, but did increase the percentage of aneuploid cells within the mosaic embryos. Adding GM-CSF to the culture media for clinical use requires further studies either on human or animal models to evaluate its long-term effects.

Media composition: growth factors

Despite the fact that the fundamental principle underlying the most common method of culture media constitution is that of mimicking the natural environment of the preimplantation embryo, one major difference that remains between current embryo culture media and in vivo conditions is the absence of growth factors in vitro. Numerous growth factors are known to be present in the in vivo environment of human and nonhuman preimplantation embryos, often with peak concentrations corresponding to when fertilization and preimplantation embryo growth would occur. Although these growth factors are found in very small concentrations, they have a profound effect on tissue growth and differentiation through attachment to factor-specific receptors on cell surfaces. Receptors for many different growth factors have also been detected in human preimplantation embryos. Preimplantation embryos themselves express many growth factors. The growth factors and receptors are metabolically costly to produce, and thus their presence in the environment of the preimplantation embryo and in the embryo respectively strongly implies that embryos are designed to encounter and respond to the corresponding factors. Studies of embryo coculture also indirectly suggest that growth factors can improve in vitro development. Several animal and human studies attest to a probable beneficial effect of addition of growth factors to culture media. However, there is still ambiguity regarding the exact role of growth factors in embryonic development, the optimal dose of growth factors to be added to culture media, the combinatorial effect and endocrine of growth factors in embryonic development.

Colony-stimulating factor 2 inhibits induction of apoptosis in the bovine preimplantation embryo

PROBLEM

Addition of colony-stimulating factor 2 (CSF2) to culture medium increases post-transfer survival of bovine embryos. Here we provide evidence that one mechanism by which CSF2 affects the embryo is through inhibition of apoptosis.

METHOD OF STUDY

In the first experiment, genes and pathways whose expression were regulated by CSF2 were identified by microarray analysis. Embryos were treated with 10 ng/ml CSF2 or vehicle at Day 5 after insemination; morulae were selected for microarray analysis at Day 6. In a second experiment, antiapoptotic effects of CSF2 were determined. Embryos were treated with CSF2 or vehicle at Day 5. On Day 6 (24 h after treatment), morulae were cultured for 15 h at either 42°C (a temperature that induces apoptosis) or 38.5°C (cow body temperature).

RESULTS

In the first experiment, a total of 214 genes were differentially regulated and 160 of these could be annotated (67 upregulated genes and 93 downregulated genes). Differentially expressed genes could be placed in 13 biological process ontologies in four functional groups (development and differentiation process, cell communication, apoptosis and cell adhesion). Antiapoptotic effects of CSF2 were confirmed in the second experiment because the magnitude of the increase in TUNEL positive cells caused by heat shock was reduced by CSF2.

CONCLUSION

CSF2 blocks apoptosis in bovine embryos through actions associated with regulation of genes controlling apoptosis.

The importance of growth factors for preimplantation embryo development and in-vitro culture

PURPOSE OF REVIEW

The present paper reviews evidence that preimplantation embryos are naturally exposed and designed to respond to growth factors during preimplantation development.

RECENT FINDINGS

Recent studies have demonstrated that in-vivo human preimplantation embryos are exposed to a mixture of many different growth factors, expressed by the follicles, oviducts and endometrium. Receptors for many of these growth factors have also been shown to be expressed by preimplantation embryos, suggesting a functional role during preimplantation development. Studies of in-vitro fertilization in both animals and humans indicate that in-vitro culture of embryos in conventional media lacking growth factors can result in suboptimal growth and a variety of short-term and long-term developmental abnormalities. Studies of embryo coculture indirectly suggest that growth factors can improve in-vitro development. Many studies of defined growth factor supplements demonstrate that their inclusion in culture media can substantially improve preimplantation development and efficacy of in-vitro fertilization, and may reduce long-term developmental abnormalities as well.

SUMMARY

Embryos are naturally exposed to a complex mixture of growth factors that play an important role in preimplantation embryo development and that are likely to be of substantial benefit if added to in-vitro culture media.

Developmental potential of isolated blastomeres from early mouse embryos in the presence and absence of LIF and GM-CSF

PURPOSE

The aim of this study was to investigate the developmental potential of isolated blastomeres in the presence and absence of leukemia inhibitory factor (LIF) and granulocyte-macrophage colony stimulating factor (GM-CSF).

METHODS

The blastomeres of two (1/2) and eight cells (1/8) embryos were isolated and cultured in T6 medium in the presence and absence of LIF (1,000 IU/ml) and or GM-CSF (2 ng/ml) up to 120 h. The diameter and cell number of blastocysts were measured.

RESULTS

The developmental rates of 1/2 isolated blastomeres developed to blastocysts stages in the presence and absence of LIF and GM-CSF were 45.80, 35.10 and 48.66, 41.66, respectively. The diameter of blastocysts was higher in GM-CSF group and total cell number of blastocyst in both treated groups was higher than control (P < 0.05). No 1/8 blastomeres developed to morula and blastocyst stages.

CONCLUSIONS

LIF and GM-CSF could improve the development of 1/2 isolated blastomeres.