Granulocyte macrophage colony stimulating factor (GM-CSF) is a cytokine/growth factor produced by epithelial cells that exerts embryotrophic effects during the early stages of embryo development. We performed a systematic review, and six studies that were performed in humans undergoing assisted reproduction technologies (ART) were located. We wanted to evaluate if embryo culture media supplementation with GM-CSF could improve success rates. As the type of studies and the outcome parameters investigated were heterogeneous, we decided not to perform a meta-analysis. Most of them had a trend favoring the supplementation with GM-CSF, when outcomes were measured in terms of increased percentage of good-quality embryos reaching the blastocyst stage, improved hatching initiation and number of cells in the blastocyst, and reduction of cell death. However, no statistically significant differences were found in implantation and pregnancy rates in all apart from one large multicenter trial, which reported favorable outcomes, in terms of implantation and live birth rates. We propose properly conducted and adequately powered randomized controlled trials (RCTs) to further validate and extrapolate the current findings with the live birth rate to be the primary outcome measure.
Assisted reproduction technologies (ARTs) are those methods that treat subfertility by providing the medical means to overcome the pathological obstacles in the fertilization process in a controlled laboratory environment, mimicking to a large extent the biological reproductive processes. Various factors have an impact on these processes, with the unfortunate upshot that successful fertilization does not invariably lead to the birth of a healthy offspring, as the growth and development of even confirmed embryo(s) in the laboratory does not always result in successful implantation, clinical pregnancy, and birth. For this reason, different culture media of the preimplantation embryo have been developed, which first appeared on the market in the early 80s [
Granulocyte macrophage colony stimulating factor (GM-CSF) is a cytokine/growth factor produced by epithelial cells under the influence of estrogens, in the human uterus and oviducts, which promotes hematopoiesis through monocyte and granulocyte proliferation and differentiation [
The aim of this study is to systematically review the published data on the benefit of GM-CSF with regard to outcome parameters in women undergoing ART.
This systematic review was conducted in accordance with the PRISMA guidelines [
A broad range search strategy was developed using PubMed, with no language or study design restrictions and search period running from 1966 to August 2012. Reference lists of relevant articles were hand-searched for potentially eligible studies (“snowball” procedure). The National Institute of Clinical Excellence (NICE) fertility assessment and treatment guidelines were also hand-searched. Relevant “letters to the editor” and data coming from conferences on previously published or unpublished series were examined for potentially useable information.
Study authors were tried to be contacted for methodological clarifications, especially for missing data.
Studies assessing the effect of GM-CSF, employed as a medium supplement, on outcome parameters in human IVF programs, as compared with a matched control group where this intervention was not performed were considered in this systematic review. All study designs were included.
Case series, case reports, and animal studies were excluded.
Collected data included general information (title, author, year, journal, and geographical and clinical settings), study characteristics (design, followup, and inclusions/exclusions), participants’ characteristics (cause and duration of preexisting subfertility, age of the women, and different protocols for ovarian stimulation IVF, different culture media, conditions, and GM-CSF concentrations), and results (number of participants, reference population) as reported in Table
Study design parameters and characteristics.
Author, year | Study design | Number of |
Patient characteristics |
GM-CSF |
Control |
ART |
---|---|---|---|---|---|---|
Sjöblom et al., 1999 [ |
Prospective |
99 |
N/A | 2 ng/mL | 20 |
IVF |
| ||||||
Kim et al., 2001 [ |
Prospective |
154 |
Women aged 28–39.6 yrs | 2 ng/mL | 10 |
IVF/ICSI |
| ||||||
Sjöblom et al., 2001 [ |
RCT |
62 (2–4 cell |
N/A | 2 ng/mL | 20 |
IVF/ICSI |
| ||||||
Shapiro et al., 2003 [ |
RCT |
72 patients |
N/A | N/A | Quinn’s Advantage |
IVF |
| ||||||
Agerholm et al., 2010 [ |
RCT |
73 women |
Women aged 25–37 yrs |
2 ng/mL | Blast Assist |
IVF/ICSI |
| ||||||
Origio website, 2011 [ |
RCT |
1319 |
Women with |
2 ng/mL | Media without |
IVF/ICSI |
In order to reduce bias (extraction, recording, conformity, and retrieval), three authors (CS, EV, and MC) performed the primary evaluation of titles and abstracts identified through the search and provided the list of potentially eligible studies. Each author extracted the data independently from the others, using the agreed data extraction form. If multiple publications using the same cohort were identified, the most recent or more complete publication was used for data extraction, but information from all relevant publications was used if required. Two authors (CS and EV) performed the final selection of the potential eligible studies of this review. Disagreements were resolved by team consensus.
Based on extracted data, the quality of the included studies was evaluated using the Quality of Reporting of Meta-analyses (QUOROM) [
A search strategy was carried out based on the following MESH headings: “Granulocyte Macrophage Colony Stimulating Factor” OR “GM-CSF” AND “Reproductive Medicine” OR “Reproductive Techniques, Assisted” OR “ART” OR “
The primary outcome measure was live birth per woman/couple. Additional outcome measures included clinical pregnancy per woman/couple (defined as evidence of a fetal heart on ultrasound at seven weeks), miscarriage rate (defined as the number of miscarriages divided by the number of clinical pregnancies), fertilization rate (rate of oocytes fertilized per oocytes retrieved), and laboratories parameters, such as progression of embryos to blastocyst stage, blastocyst performance and hatching, and chromosomal abnormalities of the embryos.
The search algorithm yielded 153 records; of them, 112 were excluded as irrelevant on the basis of title and abstract. The full-text articles of the remaining 41 studies were obtained and assessed according to the eligibility criteria. Six studies were identified [
Outcome parameters: GM-CSF versus control.
Embryo cell number (72 hrs) | Normal embryo development on day 3 | Embryos reaching blastocyst stage | Hatching initiation of blastocysts | Total cell number in blastocysts |
Mitotic index | Mean number of apoptotic cells in blastocyst/TUNEL clusters | Embryos reaching morula stage | Clinical pregnancy rate | Chromosomal constitution of embryos | Implantation rate | Live birth rate | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Sjöblom et al., 1999 [ |
76% versus 30% | 78% versus 47% | 35% higher with GM-CSF | 80% increase in GM-CSF treatment | ||||||||
Kim et al., 2001 [ |
35% versus 24% | |||||||||||
Sjöblom et al., 2001 [ |
|
|
||||||||||
Shapiro et al., 2003 [ |
6.1 versus 5.8 | 50% increase in GM-CSF group | 47% versus 50% | 32% versus 25% | ||||||||
Agerholm et al., 2010 [ |
50% versus 28.1% | 34.8% versus 33.3% | ||||||||||
Origio website, 2011 [ |
24.5% versus 17% | 29.6% versus 23.1% (per cycle) |
Sjöblom et al. [
The same study group [
Kim et al. [
The RCT by Shapiro et al. [
The recent multicenter RCT conducted by Agerholm et al. [
The largest multicenter (
The average quality of all studies was median, with the multicenter RCT of ORIGIO a/s [
This is the first systematic review on the addition of GM-CSF to embryo culture media. It highlights the potential role of GM-CSF when added to the culture media of the preimplantation embryo during IVF. Different study groups have produced favorable results as concerning the role of the specific cytokine in promoting cell proliferation, viability, and integral progression through the early stages of embryo development. All groups were in agreement regarding the beneficial effect of cytokine enhancement on pre-implantation embryo development, albeit some differing results were reported as to its effect on the implantation and clinical pregnancy rate, whereas only one—large though—RCT ended up with positive results in terms of live birth rates.
On one hand, these findings are important, as blastocyst formation is to a degree indicative of normal embryo development progression and provides a sounder basis, on which the outcome following embryo transfer is predictable. On the other, implantation and especially clinical pregnancy rates, were not significantly improved in all three of the six studies of the review, where it was taken into account [
Most of the studies reported parameters at the blastocyst stage; culture at this stage provides a means for autoselecting the most developmentally competent embryos for transfer to patients as well as for achieving a better synchronization between the embryo stage and uterine development [
In terms of quality, the current review has a number of limitations, which mainly reflect the respective limitations of the individual studies. Although a plethora of records were originally retrieved during our search, we ended up with only six applied on humans that were included in this review. The exclusion criteria did not allow the inclusion of animal studies, which were numerous. In the same context, another fundamental problem was that missing information limited our ability to explore a relationship between different drugs, doses, or protocols used for IVF, type of subfertility, age group, and pregnancy occurrence (especially live birth), although our initial intention was to explore these parameters. Of note, we found one study where GM-CSF was administered directly to women with habitual abortions in their history, ending up with favourable results [
The beneficial nature of GM-CSF in terms of clinical pregnancy rates has yet to be resolved, although there is good evidence for women with >1 miscarriage in their personal history, since published data presents differing results and contradicting views on the cytokine effect beyond embryo transfer, all of which require further research for optimal elucidation. We propose additional properly conducted and adequately powered RCTs to further substantiate and extrapolate the current findings with the live birth rate to be the primary outcome measure. These should preferably treat infertile women with similar baseline characteristics and causes of subfertility as the reference group so as to provide clear insight into the effects of the addition of the factor on IVF. As stated above, various confounders must be taken into account, such as age of the woman, type of subfertility, doses and/or durations of protocol drugs, socioeconomic index, and parity. Moreover, the target of these studies should preferably involve special subgroups of subfertile women, such as women with unexplained subfertility and repeated implantation failures or recurrent miscarriage and those of an advanced age. Finally, cost-effectiveness needs to be clearly demonstrated as well as, most importantly, any potential genetic and/or chromosomal consequences incurred by the supplementation of GM-CSF manifesting as abnormalities in the health of the individual in childhood and/or in adult life. It may be—unavoidably—some time before epidemiological studies and their proper systematic reviews and meta-analyses are able to compile assemble the follow-up times required to fully address long-term effects.
The authors report no conflict of interests. The authors alone are responsible for the content and writing of the paper.