Improved pregnancy rate after transfer of embryos grown in human fallopian tubal cell coculture

Bovine Oviduct Epithelial Cell-Derived Culture Media and Exosomes Improve Mitochondrial Health by Restoring Metabolic Flux during Pre-Implantation Development

Oviduct flushing is enriched by a wide variety of nutrients that guide the 3-4 days journey of pre-implantation embryo through the oviduct as it develops into a competent blastocyst (BL). However, little is known about the specific requirement and role of these nutrients that orchestrate the early stages of embryonic development. In this study, we aimed to characterize the effect of in vitro-derived bovine oviduct epithelial cell (BOECs) secretion that mimics the in vivo oviduct micro-fluid like environment, which allows successful embryonic development. In this study, the addition of an in vitro derived BOECs-condition media (CM) and its isolated exosomes (Exo) significantly enhances the quality and development of BL, while the hatching ability of BLs was found to be high (48.8%) in the BOECs-Exo supplemented group. Surprisingly, BOECs-Exo have a dynamic effect on modulating the embryonic metabolism by restoring the pyruvate flux into TCA-cycle. Our analysis reveals that Exo treatment significantly upregulates the pyruvate dehydrogenase (PDH) and glutamate dehydrogenase (GLUD1) expression, required for metabolic fine-tuning of the TCA-cycle in the developing embryos. Exo treatment increases the influx into TCA-cycle by strongly suppressing the PDH and GLUD1 upstream inhibitors, i.e., PDK4 and SIRT4. Improvement of TCA-cycle function was further accompanied by higher metabolic activity of mitochondria in BOECs-CM and Exo in vitro embryos. Our study uncovered, for the first time, the possible mechanism of BOECs-derived secretion in re-establishing the TCA-cycle flux by the utilization of available nutrients and highlighted the importance of pyruvate in supporting bovine in vitro embryonic development.

Impact of embryo co-culture with cumulus cells on pregnancy & implantation rate in patients undergoing in vitro fertilization using donor oocyte

Background & objectives:

Cumulus cell co-culture of embryo had been found to be beneficial for achieving better pregnancy and implantation rate (IR). The present study was aimed to evaluate efficiency of cumulus co-culture technique over simple culture of embryo in terms of pregnancy rate (PR) and IR in patients undergoing treatment for infertility using donor oocytes fertilized by intracytoplasmic sperm injection.

Methods:

This was a quasi-experimental study between control and study groups. The primary endpoint was achievement of pregnancy. Control group included 508 women who underwent embryo development without cumulus cell co-culture and study group included 394 women who underwent embryo development with cumulus cell co-culture using donor's cumulus cells.

Results:

The present study demonstrated a significant increase in the IR (37.2 vs 24.2%, P<0.001) and in PR (45.7 vs 37.8%, P<0.05) in study group than in control group. The PR and IR were found to be higher in study group, among all groups of women, grouped on the basis of different indications for use of donor oocytes.

Interpretation & conclusions:

Cumulus cell co-culture technique was found to be more effective than simple culture technique for embryo development in women undergoing treatment for infertility using donor oocytes fertilized by intracytoplasmic sperm injection.

Potential Therapy for Neisseria Gonorrhoeae Infections With Human Chorionic Gonadotropin

The scientific evidence suggests that Neisseria gonorrhoeae (NG) infects human fallopian tubes by molecular mimicry in which pathogens act like a ligand to bind to epithelial cell surface human chorionic gonadotrophin (hCG)/luteinizing hormone (LH) receptors. The hCG-like molecule has been identified as ribosomal protein L12 in NG coat surface. Human fallopian tube epithelial cells have been shown to contain functional hCG/LH receptors. As previously shown in human fallopian tube organ and cell culture studies, cellular invasion and infection can be prevented by exposing the cells to excess hCG, which would outnumber and outcompete NG for receptor binding. Based on these data, we suggest testing hCG in clinical trials on infected women.

Effects of Coculture With Immune Cells on the Developmental Competence of Mouse Preimplantation Embryos in Vitro and in Utero

The aim of this study was to establish a coculture system using immune cells as well as an in vitro model for inflammatory conditioning using RAW 264.7 mouse macrophages activated by lipopolysaccharide. The direct and indirect coculture systems were applied to evaluate the influence of embryo-to-cell direct or indirect secretory molecules from the cocultured cells. Blastulation rate in vitro (94.6% vs 76.9%, P < .05) and implantation rate in utero (43.3% vs 17.6%, P < .01) were significantly increased in direct coculture with activated RAW 264.7 cells compared to control. We also found the embryotrophic effects in vitro in the indirect coculture system. Our results indicate that coculture of mouse preimplantation embryos with immune cells could improve the developmental competence in vitro and in utero. Taken together, RAW 264.7 cells secret embryotrophic molecules, and it suggests the valuable insights that immune cells could improve in vitro culture conditions of preimplantation embryos.

The human oviduct transcriptome reveals an anti-inflammatory, anti-angiogenic, secretory and matrix-stable environment during embryo transit

The human oviduct serves as a conduit for spermatozoa in the peri-ovulatory phase and nurtures and facilitates transport of the developing embryo for nidation during the luteal phase. Interactions between the embryo and oviductal epithelial surface proteins and secreted products during embryo transit are largely undefined. This study investigated gene expression in the human oviduct in the early luteal versus follicular phases to identify candidate genes and biomolecular processes that may participate in maturation and transport of the embryo as it traverses this tissue. Oviductal RNA was hybridized to oligonucleotide arrays and resulting data were analysed by bioinformatic approaches. There were 650 genes significantly down-regulated and 683 genes significantly up-regulated (P<0.05) in the luteal versus follicular phase. Quantitative real-time PCR, immunoblot analysis and immunohistochemistry confirmed selected gene expression and cellular protein localization. Down-regulated genes involved macrophage recruitment, immunomodulation and matrix-degeneration, and up-regulated genes involved anti-inflammatory, ion transport, anti-angiogenic and early pregnancy recognition. The oviduct displayed some similarities and differences in progesterone-regulated genes compared with the human endometrium. Together, these data suggest a unique hormonally regulated environment during embryo development, maturation and transport through human oviduct and some conservation of progesterone signalling in tissues of common embryological origin. The oviduct serves as a conduit for spermatozoa in the peri-ovulatory phase and it nurtures and facilitates transport of the developing embryo during the luteal phase of the menstrual cycle, although precise interactions between the embryo and oviductal epithelium and secreted products are largely undefined. Herein, we investigated gene expression in human oviduct to identify candidate genes and processes that may participate in maturation and transport of the embryo as it develops implantation competence. Total RNA from human ampullary oviducts in the early luteal versus follicular phases was isolated and hybridized to oligonucleotide arrays. The data, analysed by bioinformatic approaches, revealed that 650 genes were significantly down- and 683 genes were significantly up-regulated in the luteal phase. Quantitative real-time PCR, immunoblot analysis and immunohistochemistry confirmed selected gene expression and cellular protein localization. The data demonstrated down-regulation of genes involved in macrophage recruitment, immunomodulation and matrix degeneration and up-regulation of ion transport and secretions, as well as anti-angiogenic and early pregnancy recognition. Together, these data suggest a unique hormonally regulated environment during embryo development, maturation and transport through the human oviduct and provide insight into mechanisms influencing acquisition of implantation competence of the human embryo during its passage through the oviduct en route to the uterine endometrium.

Effect of mouse cumulus cells on the in vitro maturation and developmental potential of bovine denuded germinal vesicle oocytes

We investigated the effect mouse cumulus cells (mCCs) on the in vitro maturation (IVM) and developmental potential of bovine denuded germinal vesicle oocytes (DOs). Cumulus–oocyte complexes (COCs), DOs and DOs cocultured with either mCCs (DOs + mCCs) or bovine cumulus cells (bCCs; DOs + bCCs) were subjected to IVM. The meiosis II (MII) rates of DOs, glutathione (GSH) contents, zona pellucida (ZP) hardening and parthenogenetic blastocyst rates of MII oocytes were determined. The relative expression levels of bone morphogenetic protein 15 (BMP-15) and growth differentiation factor 9 (GDF-9) in MII oocytes were measured using quantitative real-time polymerase chain reaction (PCR). mCCs significantly increased the MII rate of DOs from 53.5 ± 3.58% to 69.67 ± 4.72% (p < 0.05) but had no effect on the GSH content (2.17 ± 0.31 pmol/oocyte with mCCs, 2.14 ± 0.53 pmol/oocyte without mCCs). For the DOs + mCCs group, the BMP-15 and GDF-9 expression levels were significantly higher and the ZP dissolution time was significantly lower (162.49 ± 12.51 s) than that of the DOs group (213.95 ± 18.87 s; p < 0.05). The blastocyst rate of the DOs + mCCs group (32.56 ± 4.94%) was similar to that of the DOs group (31.75 ± 3.65%) but was significantly lower than that of the COCs group (43.52 ± 5.37%; p < 0.05). In conclusion, mCCs increased the MII rate of DOs and expression of certain genes in MII oocytes, and decreased the ZP hardening of MII oocytes, but could not improve their GSH content or developmental potential.

The morphological and functional observation of the gap junction proteins in the oviduct epithelia in young and adult hamsters

The histological morphology of oviduct epithelia have been described well, however, the expression pattern of the gap junction proteins in the cells, and the function related with the proteins, such as [Ca2+]i dynamics pattern of living oviduct epithelia at different ages have not been clarified. We used immunohistochemistry to compare the expression pattern of gap junction proteins in the cells of the young and adult groups. Moreover, we used real-time confocal microscopy to observe the spontaneous Ca2+ oscillation (spontaneous fluctuation) in freshly isolated epithelia (ciliated cells) in ampulla potion of oviduct from the two groups. The results show as demonstrated by immunohistochemistry the gap junction proteins (Cx26, Cx32 and Cx43) formed a well-regulated expression in the young animals, but not in the adult animals. In addition, the [Ca2+]i dynamics of ciliated cells in freshly oviduct epithelia have a spontaneous fluctuation pattern that occurs without any stimulation in the young animals, but this pattern was not observed in the adult animals. In conclusions, our findings suggest that gap junctions regulate the spontaneous fluctuation of [Ca2+]i dynamics in ciliated cells of oviduct epithelia in young animals.

Culture systems: embryo co-culture

During the 1970s, domestic animal biotechnology, i.e., embryo transfer in farm animals, was confronted with the problem of embryonic developmental arrest observed in vitro, especially during the cycle in which maternal to zygotic transition (MZT) cycle takes place. In farm animals, obtaining blastocysts is mandatory, as transfer at earlier stages results in expulsion of the embryo from the vagina. In humans, the first attempts to obtain blastocysts with classical culture media were disappointing, and the use of a coculture strategy was naturally tempting: the first significant results of successful blastocyst development were obtained in the early 1980s, using trophoblastic tissue as a feeder layer in order to mimic an autocrine embryotrophic system. The next supporting cell systems were based on oviduct epithelial cells and uterine cells in order to achieve a paracrine effect. Non-hormone dependence was then demonstrated with the use of prepubertal cells, and finally with the use of established cell lines of nongenital origin (African Green Monkey Kidney, Vero cells). The embryotrophic properties are linked to features of "transport epithelia." Vero cells have been extensively used in human ART, and most of our knowledge about the human blastocyst was gathered with the use of this technology. Coculture is still in current use, but with systems that employ autologous uterine cells. Results following the use of this technology in human ART are superior to those observed with the use of sequential media. The benefit is linked to the release of free radical scavengers and growth factors by the feeder cells. In animal biotechnology, an important part of the "precious embryos," i.e., those resulting from cloning technology, involves coculture with buffalo rat liver (BRL) cells or Vero cells.

Oviductal cells and early conception

The ability to bypass the oviduct by fertilizing human oocytes in vitro and then transferring the ensuing embryos into the uterine environment to produce pregnancies that can be carried to term (assisted reproductive technology, ART) has made the real functional significance of the fallopian tube come under debate. The question has been raised as to whether the oviduct is a simple conduit, providing for the transport of gametes and embryos, or whether it has any functional relevance to early conception. In the field of ART, some reports claim that transfer of embryos either to the uterus or to the oviduct yield similar results, while a greater amount of evidence confirms that tubal transfers are associated with higher pregnancy and take home baby rates, suggesting that unknown factors in the oviduct favour fertilization and embryo viability. This review attempts to provide some answers to questions about the role of oviductal cells in vivo during early conception and in vitro in the field of ART.

Localization of immunoreactive gonadotropin-releasing hormone and relative expression of its mRNA in the oviduct during pregnancy in rats

This study was designed to determine the cellular and ultrastructural distribution of the gonadotropin-releasing hormone (GnRH) and the relative expression of its mRNA in the oviduct of rats during different time points (days 7, 9, 16, and 20) of pregnancy. Immunofluorescent localization and confocal microscopic techniques were used to determine the cellular distribution of GnRH in the oviduct. Immunogold electron microscopy indicated its localization at the ultrastructural level, and real-time PCR was used to study the expression pattern of GnRH mRNA in the oviduct during pregnancy. In general, GnRH was localized within the epithelial cells lining the oviductal lumen at each selected time point. A strong correlation between the fluorescence intensity of GnRH-immunoreactive cells and the relative expression of GnRH mRNA was noted on days 7 and 16, followed by a plateau by day 20. At the ultrastructural level, uniform labeling of colloidal gold particles was observed in secretory vesicles and lamella of the luminal epithelium as well as the lumen of the oviduct. Collectively, these results demonstrate for the first time that the oviductal epithelium synthesizes and secretes the decapeptide GnRH during pregnancy in rats, which may have a possible role in postimplantation embryonic development and the maintenance of pregnancy.

Human blastocyst culture and derivation of embryonic stem cell lines

Human embryonic stem cell (hESC) biology is expected to revolutionize the future of medicine by the provision of cell-based therapies for the treatment of a variety of deliberatig diseases. The tremendous versatility of hESCs has reinforced this hope. To understand the biology of these mysterious cells and attempt to differentiate them into desirable tissues, bona fide hESCs that maintain their stability with time are required for research and clinical application. This review discusses the various protocols to derive and propagate hESCs from high quality embryos. The nature and properties of hESCs are also described together with unanswered questions that need to be addressed if this science is to be taken to the bedside.

Cumulus coculture and cumulus-aided embryo transfer increases pregnancy rates in patients undergoing in vitro fertilization

OBJECTIVE

To evaluate the effect of the use of cumulus-aided embryo transfer on pregnancy rates. To study the proximity of expanded cumulus cells to the developing embryo. To document by light microscopy the anchoring of day 3 to day 4 embryos by the expanded cumulus cells. To demonstrate by transmission electron microscopy the cellular activity of the expanded cumulus cells. To evaluate the expression of growth factors (vascular endothelial growth factor, interleukin-6, insulin-like growth factor I) that are secreted by the cumulus cells.

DESIGN

A comparative study of a group of women undergoing cumulus coculture and cumulus-aided embryo transfer, with those who underwent cumulus coculture but did not undergo cumulus-aided embryo transfer. The endpoint was the achievement of pregnancy.

SETTING

Department of Infertility Management and Assisted Reproduction, Jaslok Hospital and Research Centre, Mumbai, India.

PATIENT(S)

Five hundred seventeen women undergoing treatment for infertility using intracytoplasmic sperm injection and embryo transfer and fulfilling set criteria. To validate our initial results, we conducted a similar study on 208 women where randomization was performed.

INTERVENTION(S)

Embryos were cocultured with the patient's own cumulus cells and were transferred into the uterus with approximately 30 microL of the expanded cumulus cells.

MAIN OUTCOME MEASURE(S)

Pregnancy, implantation, and multiple gestation rates.

RESULT(S)

Our study demonstrated a significant increase in the implantation rate in the study group (group A) of 25.6% versus 14.5% in the control group (group B) and a significant increase in the pregnancy rate in the study group (group A) of 47.6% versus 34% achieved in the control group (group B). Although the incidence of multiple gestation was similar (38.6% in the study group and 32.9% in the control group), the higher-order multiple gestation rate was significantly more in the study group as compared with the control group (18.1% vs. 2.4%). Similar pregnancy and implantation rates were observed in the randomized study.

CONCLUSION(S)

This study demonstrates the efficacy of cumulus-aided embryo transfer, using autologous cumulus cells. It indicates a significant increase in implantation and pregnancy rates. The results suggest that cumulus cells play an important role in embryonic development, and that they may provide a mechanism to improve embryo-uterine adhesion by physical proximity, and by secreting cytokines and growth factors required to aid the implantation process.

Human Embryo Culture

Human embryonic stem cells (hESCs) are derived from preimplantation embryos. Approximately 60% of human embryos are blocked during in vitro development. Although statistics are inconclusive, experience demonstrates that hESCs are more effectively derived from high-quality embryos. In this way, optimal human embryo culture conditions are a crucial aspect in any derivation laboratory. Embryos can be cultured solely with sequential media or cocultured on a monolayer of a given cell type. This chapter explores general aspects of human embryonic development, the concept of sequential culture and coculture, and specific protocols and procedures in which the authors are experienced, including the results obtained.

GnRH antagonist improved blastocyst quality and pregnancy outcome after multiple failures of IVF/ICSI-ET with a GnRH agonist protocol

BACKGROUND

To determine the efficacy of a gonadotrophin-releasing hormone (GnRH) antagonist, cetrorelix, in improving the quality of embryos and pregnancy outcome, we performed a study in patients with a history of multiple failures of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles with a GnRH agonist (GnRHa) long protocol.

METHODS

Forty women with no live births after conventional IVF or ICSI embryo transfer (ET) and subsequent blastocyst transfer (BT) with a GnRHa long protocol entered this study. The treatment protocol consisted of a daily dose of clomiphene citrate 100 mg for 5 days and gonadotrophin injections daily from cycle day 4 onward. Cetrorelix, 0.25 mg/day, was started when the leading follicle reached 14 mm. Induction of ovulation was triggered with human chorionic gonadotrophin (HCG) (N = 36) or GnRHa (N = 4). It was possible to perform BT in 38 patients.

RESULTS

Comparison of the results with the results for BT with the previous GnRHa protocol showed no significant differences in number of oocytes retrieved or the zygote- and blastocyst-development rate. With the cetrorelix protocol, however, number of patients whose embryos had developed to at least one expanded blastocyst on day 5 was significantly higher than with the GnRHa protocol (25 vs. 9) (p < 0.001), and 16 of the women became pregnant (42.1%), with 7 delivering 9 infants, 4 ending in abortion (25%), and 5 in progressing.

CONCLUSIONS

The use of a GnRH antagonist in controlled ovarian hyperstimulation improves the outcome of pregnancy of patients with a history of multiple failure of IVF/ICSI-ET in a GnRHa protocol, most likely due to improvement of the quality of the blastocysts generated.

Coculture with a human granulosa cell line enhanced the development of murine preimplantation embryos via SCF/c-kit system

PURPOSE

To evaluate the effect on the coculture of murine embryos with a human ovarian granulosa tumor derived cell line (KGN cells).

METHODS

We observed microscopically the growth of murine preimplantation embryos in the coculture system with KGN cells or in the presence with exogenous stem cell factor (SCF). The reverse transcriptase-polymerase chain reaction (RT-PCR) method was used to analyze the gene expression of SCF in KGN cells cocultured with murine embryos.

RESULTS

The coculture system with KGN cells significantly increased the rate of embryo development to late blastocyst and to hatching stage. We also found that coculture with murine embryos enhanced the gene expression of SCF in KGN cells. Adding human recombinant SCF to the medium significantly enhanced embryo development to late blastocyst and hatching stage.

CONCLUSIONS

KGN cells may facilitate preimplantion embryo development through SCF/c-kit paracrine system.

Preimplantation genetic diagnosis as a novel source of embryos for stem cell research

The generation of human embryonic stem (hES) cells has captured the public and professional imagination, largely due their potential as a means of overcoming many debilitating and degenerative diseases by cell replacement therapy. Despite this potential, few well-characterized hES cell lines have been derived. Indeed, in the UK, despite several centres having been active in this area for more than 2 years, there are as yet no published reports of human embryonic stem cells having been generated. Part of the reason for this lack of progress may relate to the quality of embryos available for research. Embryos surplus to therapeutic requirements following routine assisted reproduction treatment are often of poor quality and a large proportion may be aneuploid. This study reports a new approach to hES cell derivation. Embryos surplus to therapeutic requirements following preimplantation genetic diagnosis were used. Although unsuitable for embryo transfer due to the high risk of genetic disease, these embryos are from fertile couples and thus may be of better quality than fresh embryos surplus to assisted reproduction treatment cycles. Embryos donated after cryopreservation were also used, and putative hES lines were derived from both sources of embryos. The cell lines described here are thought to be the first reported hES cell lines to have been derived in the UK.

A novel role of luteinizing hormone in the embryo development in cocultures

Bovine oviductal epithelium contains LH receptors, which function in the increase of synthesis of oviductal glycoprotein (OGP). As with cocultures of embryos with oviductal epithelial cells, OGP is thought to promote early embryonic growth and development. These findings led us to test the hypothesis that LH treatment of cocultures further increases embryo development through OGP mediation. Coculture of > or=10 two-cell bovine embryos with bovine oviductal epithelial cells increased the development of the embryos into blastocysts. Treatment of these cocultures with hCG, used as a surrogate for LH because of its stability and purity, further increased embryo development. The hCG effect is dose dependent and hormone specific and requires the dimer conformation and the presence of LH receptors in oviductal epithelial cells. The inhibition of OGP synthesis and prevention of protein kinase A activation blocked the hCG effect in cocultures. Reverse transcription polymerase chain reaction and indirect immunofluorescence with laser scanning confocal microscopy demonstrated the presence of LH receptors in bovine oocytes, embryos, and blastocysts. However, embryo LH receptors may not have played any role in the beneficial hCG effects in cocultures. These findings suggest that elevated periovulatory LH levels may promote preimplantation embryo development in oviducts. These results have important implications for assisted reproductive technologies in which cocultures are used to improve pregnancy rates.

Expression and regulation of interleukin-8 in human fallopian tubal cells

OBJECTIVE

The human fallopian tube creates the microenvironment for fertilization and early embryogenesis. Salpingitis may result in infertility and ectopic pregnancy by causing tubal blockage and hydrosalpinx. To better understand the relationship between infectious inflammation and tubal damage, we investigated the expression and regulation of interleukin-8 in human tubal epithelial and stromal cells in culture.

STUDY DESIGN

Human fallopian tube epithelial and stromal cell cultures were used to measure interleukin-8 messenger RNA and interleukin-8 protein levels at basal conditions and after stimulation with interleukin-1alpha and tumor necrosis factor-alpha. Northern blot analysis and enzyme-linked immunosorbent assay were used to evaluate messenger RNA and protein levels, respectively.

RESULTS

Tubal epithelial cells expressed high levels of interleukin-8 messenger RNA and secreted significantly more immunoreactive interleukin-8 into culture medium than did tubal stromal cells (2065 +/- 153 pg/mg vs 530 +/- 56 pg/mg of total protein, P <.01). Interleukin-1alpha and TNF-alpha treatments induced a concentration-dependent increase in interleukin-8 messenger RNA expression in both epithelial and stromal cells. However, at the protein level, although interleukin-1alpha and tumor necrosis factor-alpha treatments increased the secretion of interleukin-8 from stromal cells significantly, similar treatments had no effect on interleukin-8 secretion from epithelial cells.

CONCLUSION

The expression of interleukin-8 in human tubal epithelial and stromal cells is different. Interleukin-8 expression of tubal epithelial and stromal cells in response to inflammatory cytokines such as interleukin-1alpha and tumor necrosis factor-alpha also varies. This may be important in the pathogenesis of salpingitis.

Temporal effect of human oviductal cell and its derived embryotrophic factors on mouse embryo development

Mouse embryos at different stages of development were cocultured with human oviduct cells or cultured in the presence of oviduct-derived embryotrophic factor-1, -2, and -3 (ETF-1, -2, and -3) for various amounts of time within the preimplantation period. Cocultures that included the period from 48 to 72 h post-hCG stimulated cell division and increased the cell numbers in the inner cell mass (ICM) of the exposed blastocyst. Exposure of embryos to oviductal cells from 96 to 120 h post-hCG increased the cell number in the trophectoderm (TE), blastocyst size, hatching rate, attachment, and in vitro spreading of the blastocyst. ETF-1 and ETF-2 affected embryos between 48 and 72 h post-hCG by increasing the number of cells in the ICM. In contrast, ETF-3 had a more profound effect on embryos that were exposed from 96 to 120 h post-hCG, where it mostly affected the development of TE cells, leading to higher hatching rate. Human oviductal cells improved mouse embryo development partly by the production of high molecular weight embryotrophic factors. These factors had differential effects on mouse embryo development.

Establishment and characterization of an immortalized human oviductal cell line

Human oviductal cells stimulate embryo development in vitro partly by the production of embryotrophic glycoproteins. The identity of these glycoproteins is not yet known mainly because oviductal samples are limited and that the cultured parental oviductal cells cannot produce sufficient amount of embryotrophic factors for characterization. In this study, human oviductal epithelial cells (OE) were immortalized by HPV 16 E6/E7 open reading frame (ORF) by retroviral expression. The characteristics of this immortalized cell line (OE-E6/E7) were compared to the parental OE. HPV 16 E6/E7 DNA was found only in OE-E6/E7 but not in OE. Human oviduct-specific glycoprotein, estrogen receptors, and cytokeratin were found in both cell types. Both OE and OE-E6/E7 possessed telomerase activities but the former had much lower activity. OE-E6/E7 also produced glycoproteins with chromatographic behavior similar to the embryotrophic glycoproteins derived from OE. These results showed that OE-E6/E7 retained a number of characteristics of OE. The development of preimplantation mouse embryo was significantly better after coculture with OE-E6/E7 when compared to medium alone culture in term of blastulation rates (52% vs. 32%) and blastocyst diameter (113.0 +/- 2.07 microm vs. 83.9 +/- 5.23 microm). This immortalized cell line can be used as a continuous and stable in vitro system for the study of the oviductal embryotrophic activity. Mol. Reprod. Dev. 59: 400-409, 2001.

Biological factors in culture media affecting in vitro fertilization, preimplantation embryo development, and implantation

Optimal culture conditions are of paramount importance for in vitro fertilization of gametes, preimplantation embryo development, and implantation for all species. Water is the basis of all culture media, and ultrapure water should be employed. The main energy sources of a medium are lactate, pyruvate, and glucose. The concentrations of the first two vary in different media, whereas the latter is necessary mainly for the later stages (morula to blastocyst) of development. A fixed nitrogen source is essential for implantation embryo development whether this is provided by amino acids, albumin, or serum. Suboptimal culture conditions can block development. Pronuclear zygotes of most species (but not human) arrest at some point between the two-cell and the 16-cell stage. Modifying culture conditions can lead the embryos to develop through this block. Hypoxanthine also causes a two-cell block to mouse pronuclear zygotes, and this again depends largely on culture conditions. Simple culture media are bicarbonate-buffered systems with pyruvate, lactate, and glucose. Complex media, such as Ham's F-10, contain in addition amino acids and other elements found in serum. Human tubal fluid simulates the fallopian tube microenvironment. EDTA, gonadotropins, growth factors, and other substances can be included in the media to stimulate development. Coculture of embryos with oviductal cells has shown promising results.

Human embryo development and pregnancies in an homologous granulosa cell coculture system

PURPOSE

Our purpose was to determine the effects of the coculture of embryos on human granulosa cells (GCs) in patients in the first cycle of IVF-ET treatment and in patients with repeated implantation failures and to investigate the presence of specific proteins in a 48-hr GC conditioned medium and the GC ultrastructural characteristics.

METHODS

Eighteen patients with tubal or idiopathic infertility were enrolled in this study: 7 patients (Trial 1) were in the first cycle of IVF-ET treatment and 11 patients (Trial 2) had repeated implantation failures (one to five). Embryos from each patient were cocultured randomly either on homologous granulosa cells or on a conventional culture medium.

RESULTS

At the end of the coculture period (day 5 or 6), 50% of the embryos (Trial 1) reached the blastocyst stage, with respect to 35% in Trial 2. The pregnancy rate per retrieval was 14.2 and 9%, respectively, in Trial 1 and in Trial 2. Many conditioned media showed proteins of 24-29 kDa. and some of them showed additional proteins of 90 kDa. The ultrastructural analysis of GCs showed healthy, metabolically active, protein-synthesizing, and mostly steroidogenic cells.

CONCLUSIONS

GC cultures improve embryo development but not pregnancy rates both in Trial 1 and in Trial 2.

A historical perspective of the clinical evolution of the assisted reproductive technologies

The practice of assisted reproduction technology today is the result of the dedicated patient care, observation, research, and experimentation undertaken by previous generations of physicians. The building blocks of progress have been assembled over past decades, by scientists whose primary objective has been to push forward the frontiers of knowledge, in order to offer more effective methods of infertility treatment. And fortunately that process continues today. Amongst the many scientific developments that have led to the modern practice in assisted reproductive technology, a small number stand out as having had a unique importance. This historical review redraws the path through which in vitro fertilization went from an experimental to an accepted infertility treatment.

Coculture of human embryos with autologous human endometrial epithelial cells in patients with implantation failure

We have developed a coculture system with autologous human endometrial epithelial cells (AEEC) that retained many features of human endometrial epithelium. Implantation failure (IF; >3 previous cycles failed with 3-4 good quality embryos transferred) is a distressing condition in which 2-day embryo transfer repetition is the routine option. The objective of this study was to investigate the basics and to evaluate prospectively the clinical value of embryo coculture on AEEC and blastocyst transfer with their own oocytes [in vitro fertilization (IVF) patients] or with donated oocytes (oocyte donation patients) compared to a routine day 2 embryo transfer for patients with IF. Scanning electron microscopy and mouse embryo assays demonstrate that EEC from fertile and IF patients were morphologically and functionally similar; similar findings were observed in EEC obtained from fresh or frozen endometria. Clinically, 168 IVF cycles were performed in 127 patients with 3.8+/-0.2 previously failed cycles, and 80 cycles were performed in 57 patients undergoing oocyte donation with 3.0+/-0.2 previously failed cycles. Twenty IVF patients and 15 ovum donation patients with 3 previously failed cycles in whom a 2-day embryo transfer was performed were used as controls. In 88% of ovum donation cycles, at least 2 blastocysts were available for transfer, with 60.1% blastocyst formation; 2.2+/-0.1 blastocysts were transferred/cycle, and 36 pregnancies (determined by fetal cardiac activity) were obtained (32.7% implantation and 54.5% pregnancy rates). In 168 IVF cycles, 8.1+/-0.2 embryos/cycle started coculture, resulting in 49.2% blastocyst formation; 2.3+/-0.2 blastocysts were transferred/cycle, and 29 clinical pregnancies were obtained (11.8% implantation and 20.2% pregnancy rates). Fifteen cycles were canceled (9%). In oocyte donation patients with IF undergoing 2-day embryo transfer, implantation and pregnancy rates were significantly lower (4.5% and 13.3%; P < 0.01) than with coculture; however, in IVF patients with IF, results with day 2 transfer (10.7% and 35%) were similar to those with coculture. The present study demonstrates that coculture of human embryos with AEEC and blastocyst transfer is safe, ethical, and effective and constitutes a new approach to improve implantation in patients with IF undergoing ovum donation, but not in IVF patients.

Stimulation of early embryonic development in cattle by coculture with surfactant

PURPOSE

Our purpose was to determine the efficacy of Surfacten, a bovine pulmonary surfactant, on the maturation of in vitro bovine ova.

METHODS

We used Surfacten as a supplement to the coculture media both at the onset of coculture and after cleavage in bovine ova had been determined. The controls received no Surfacten.

RESULTS

The maturation rate in bovine embryos to the blastocyst stage statistically improved (P < 0.05) in the series in which Surfacten was added to the media at the onset of coculture, compared with the controls and the series in which Surfacten was added after cleavage had been determined.

CONCLUSIONS

Surfacten, a commercially available surfactant which is a naturally occurring phospholipid that dramatically increases in the cervical mucus and the ampullaris of the oviduct at or near the time of ovulation, improves the maturation of bovine embryos in vitro by making the coculture medium approach the conditions found in the oviducts.

The use of Matrigel at low concentration enhances in vitro blastocyst formation and hatching in a mouse embryo model

OBJECTIVE

To determine the effect of Matrigel at a low concentration on the growth of mouse embryos in culture.

DESIGN

Randomized case-control study of mouse embryos.

SETTING

An academic research environment.

ANIMALS

Mouse embryos.

INTERVENTION(S)

Embryos were cultured in Quinn's or Celbio's human tubal fluid (HTF) enriched with 1.5% bovine serum albumin and 0.8% liquid Matrigel. Each HTF was compared with the same medium devoid of Matrigel. Afterward, Quinn's and Celbio's HTF, both containing Matrigel, were compared directly. Embryos were cultured in four-well dishes, and their morphology and viability were assessed at 96 hours.

MAIN OUTCOME MEASURE(S)

Level of interleukin-1alpha in media collected at the end of culture.

RESULT(S)

In both types of HTF, the presence of Matrigel allowed a larger number of embryos to reach the blastocyst stage and to hatch; blastocyst morphology also was improved. These positive effects were enhanced in Quinn's HTF: embryos cultured in its Matrigel-enriched version secreted a higher level of interleukin-1alpha than those in Celbio's HTF plus Matrigel and also showed a better morphology.

CONCLUSION(S)

In the mouse embryo model, Matrigel improves culture conditions in terms of both embryo viability and morphology, and these effects are enhanced in Quinn's HTF.

Autologous endometrial co-culture in patients with repeated failures of implantation after in vitro fertilization-embryo transfer

PURPOSE

Our purpose was to evaluate the effect of coculture on preembryo development and clinical outcome.

METHODS

Enrolled patients underwent a luteal-phase endometrial biopsy. The tissue was then enzymatically digested (collagenase) and the stromal and glandular cells were separated by differential sedimentation rates. These cells were cultured to confluence, released, and then cryopreserved until the patient's in vitro fertilization (IVF)-embryo transfer (ET) cycle. All normally fertilized oocytes were then placed on the co-cultured cells until transfer on day 3. Preembryo development on co-culture was compared to that in the patient's noncocultured previous cycle. Implantation and clinical pregnancy rates were compared to those in a control group of patients undergoing IVF during the study period who were matched for age, stimulation protocol, number of oocytes retrieved, and preembryos transferred.

RESULTS

Twenty-nine women underwent 31 cycles of IVF-ET. On day 3 the overall mean number of blastomeres per preembryo on co-culture compared to that in the patient's previous cycle was 6.3 +/- 1.8 vs. 5.6 +/- 1.2 (P = 0.04). The average percentage of cytoplasmic fragments on co-culture compared to the previous cycle was 16 +/- 9% vs. 19 +/- 9% (P = 0.32). At transfer, after preembryo selection, the mean number of blastomeres per preembryo on co-culture compared to that in the patient's previous cycle was 6.8 +/- 1.6 vs. 6.6 +/- 1.3 (P = 0.5). The implantation and clinical pregnancy rates between co-culture and the matched control group were 15% (14/93) vs. 13% (16/124) (P = 0.79) and 29% (9/31) vs. 25% (10/40) (P = 0.45).

CONCLUSIONS

There was a significant improvement in the average number of blastomeres per preembryo on co-culture compared to that in the patient's previous noncoculture cycle. The overall implantation and clinical pregnancy rates between co-culture and a matched control group were not significantly different.

The management of unexplained infertility

Unexplained infertility is a diagnosis made by exclusion after all of the standard investigations have revealed no abnormality (1). The range of the prevalence is from 6 to 60 percent (23), depending on the diagnostic criteria. This article reviews the literature in the management of unexplained infertility; published data suggest no benefit of danazol or bromocriptine. The empirical use of clomiphene citrate suggests that ovarian stimulation using clomiphene citrate can double the spontaneous pregnancy rate (52, 58, 59). Induction of ovulation with human menopausal gonadotrophin (hMG) yields an overall pregnancy rate between 2 and 26 percent per cycle (68, 74). These results seem to be lower than those reported for in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) procedures in similar patients (25-30 percent (92, 95)). Based on the literature, a rational treatment plan for treating infertility in couples with unexplained infertility includes up to four cycles of clomiphene citrate with or without intrauterine insemination (IUI). Superovulation with hMG and IUI or stimulated intrauterine insemination (SIUI) is the next step for three-cycle treatments and if unsuccessful, one of the variants of assisted reproductive techniques (ART) should be considered.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will understand the appropriate tests and work up for unexplained infertility, the various treatment options for the unexplained infertility couple including which drugs are effective and not effective, and to be able to outline an appropriate treatment plan for such patients.

Human endometrial stromal cells improve embryo quality by enhancing the expression of insulin-like growth factors and their receptors in cocultured human preimplantation embryos

OBJECTIVE

To demonstrate the mechanism by which human endometrial stromal cells improve embryo quality in coculture.

DESIGN

Randomized study.

SETTING

Academic research center.

PATIENT(S)

Patients undergoing IVF-ET.

INTERVENTION(S)

Donated human embryos were cultured randomly either alone (group A) or with human endometrial stromal cells (group B), and the embryonic expression of insulin-like growth factors (IGFs) and their receptors was detected by reverse transcriptase polymerase chain reaction after culture.

MAIN OUTCOME MEASURE(S)

The embryo frequency distribution of groups A and B before and after culture and the embryonic transcripts of the IGF family genes of the two study groups after culture were compared.

RESULT(S)

The embryo frequency distribution of the day 3 embryonic stages in groups A and B was not different. However, after culture, a statistically significant difference in blastocyst formation was observed between groups A and B. A significant increase in the expression of IGF-1, IGF-2, the IGF-1 receptor, and the insulin-receptor also was noted. Among the embryos that reached the blastocyst stage, the expression of IGF-1 and the IGF-1 receptor also was significantly different in the two study groups.

CONCLUSION(S)

Human endometrial stromal cells enhanced the expression of IGFs and their receptors in cocultured human embryos, which may be essential for improving embryo quality.

Leukemia inhibitory factor in human reproduction

PROBLEM

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine of the interleukin-6 family and has different biological actions in various tissue systems. Although named for its ability to inhibit proliferation of a myeloid leukemic cell line by inducing differentiation, it also regulates the growth and differentiation of embryonic stem cells, primordial germ cells, peripheral neurons, osteoblasts, adipocytes, and endothelial cells. LIF is crucial for successful implantation of the embryo in mice. Currently, there is an accumulation of data about the role of LIF in human reproduction.

METHOD OF STUDY

This review of the literature and of our studies focuses on the expression, regulation, and effects of LIF in the human endometrium, fallopian tube, and ovarian follicle.

RESULTS

Human endometrium expresses LIF in a menstrual cycle-dependent manner. Maximal expression is observed between days 19 and 25 of the menstrual cycle, coinciding with the time of implantation. Various cytokines and growth factors induce endometrial LIF expression in vitro. LIF receptor is expressed in endometrial tissue throughout the menstrual cycle and on human blastocysts in a stage-dependent manner. Affecting the trophoblast differentiation pathway toward the adhesive phenotype, LIF plays a role in implantation. LIF is also expressed and secreted by the epithelial cells of the fallopian tube. Its increased expression in the tubal stromal cell cultures by the inflammatory cytokines suggests a link between salpingitis and ectopic implantation in the tube. The rising follicular fluid LIF level around the time of ovulation indicates that LIF may play a role in ovulatory events, early embryonic development, and implantation.

CONCLUSIONS

There is growing evidence that LIF may be one of the entities that plays a role in human reproduction.

Coculture of human embryos with buffalo rat liver cells for women with decreased prognosis in in vitro fertilization

OBJECTIVE

The coculture of human embryos with epithelial cells may improve both embryo quality and pregnancy rates. In this current study we tested the efficacy of coculture with the buffalo rat liver cell line on pregnancy rates in women with a potentially poor prognosis for success with in vitro fertilization (previous in vitro fertilization failure, advanced maternal age, increased early follicular follicle-stimulating hormone levels, and anovulation).

STUDY DESIGN

This prospective controlled study evaluated a total of 203 women (135 coculture, 68 controls) undergoing in vitro fertilization. Implantation rates per embryo, clinical pregnancy rates, and continuing/delivered pregnancy rates were analyzed.

RESULTS

Buffalo rat liver cells, which are commercially available, are stable in coculture. Implantation rates (number of sacs with fetal heart motion per embryos transferred) were similar for coculture (19%) and control (18%) embryos. No difference in the rate of continuing/delivered pregnancies per retrieval was noted (17% coculture vs 14% control) in the group with advanced maternal age, but coculture caused a trend toward improved pregnancy rates in the group with ovulatory dysfunction (43% coculture vs 14% control) and the group with previous in vitro fertilization failure (34% coculture vs 28% control).

CONCLUSION

This is the first published controlled study to our knowledge that reports the use of the buffalo rat liver cell coculture for human in vitro fertilization in a large number of patients. Our data support consideration of buffalo rat liver coculture for in vitro fertilization for women with previous in vitro fertilization failure and possibly for patients with oocyte or ovulatory dysfunction.

Assisted hatching increases the implantation and pregnancy rate of in vitro fertilization (IVF)-embryo transfer (ET), but not that of IVF-tubal ET in patients with repeated IVF failures

OBJECTIVE

To assess the effect of augmenting IVF with assisted hatching in the treatment of patients with repeated IVF failures.

DESIGN

Prospective randomized study.

SETTING

Division of Reproductive Endocrinology and Infertility of National Taiwan University Hospital.

PATIENT(S)

From July 1993 to February 1996, 49 patients with repeatedly failed IVF were treated with assisted hatching and were compared with 51 control subjects without assisted hatching.

INTERVENTION(S)

Assisted hatching.

MAIN OUTCOME MEASURE(S)

Pregnancy rate and implantation rate per embryo after IVF-ET or IVF-tubal ET (TET) were measured.

RESULT(S)

The pregnancy rate (PR) in the assisted hatching group was found to be 36.7% compared with 19.6% in the control group, but the difference was not significant. When only patients receiving IVF-ET were considered, it was observed that the PR was significantly higher in the assisted hatching group than the control group (42.4% versus 16.1%). With IVF-TET however, the PR was found to be similar in both assisted hatching and control groups (25.0% and 25.0%, respectively). The rate of embryonic implantation in the IVF-ET patients was 11.0%, which was significantly higher than that of control embryos (3.7%).

CONCLUSION(S)

These results implied that IVF-ET, combined with assisted hatching, may improve the PR and implantation rate in patients with repeated IVF failures, but the same was not true in the case of IVF-TET.

Growth factor expression by human oviduct and buffalo rat liver coculture cells

OBJECTIVE

To characterize growth factor gene expression by passaged coculture cell lines demonstrated to enhance in vitro pre-embryo growth.

DESIGN

Ribonucleic acids isolated from the isthmus, ampullary, and fimbriae portions of the human oviduct, and from buffalo rat liver cell monolayers were subjected to Northern analysis using probes for growth factors.

SETTING

Academic tertiary care hospital.

PATIENT(S)

Two reproductive age women undergoing a hysterectomy and bilateral salpingectomy for benign gynecologic conditions consented to experimental use of their oviducts.

INTERVENTION(S)

Cell cultures were established from fresh human oviduct segments and commercially purchased buffalo rat liver cells. After two passages, total RNA was isolated from these confluent monolayers, fractionated on denaturing agarose gels, transferred to nylon membranes, and analyzed by Northern hybridization using complementary DNAs from epidermal growth factor (EGF), stem cell factor, also known as Kit-ligand, colony-stimulating factor-1 (CSF), leukemia inhibitory factor, and interleukin-6 (IL-6). Radioactively labeled probes were prepared by in vitro transcription or by 5' end labeling. After hybridization, blots were washed at increasing strigencies to remove nonspecifically bound radioactivity and subjected to autoradiography.

RESULT(S)

Human oviduct coculture cells express EGF (kit-ligand), CSF, leukemia inhibitory factor, and IL-6. Buffalo rat liver cells contain the messenger RNA transcripts for kit-ligand and CSF.

CONCLUSION(S)

Human oviduct and buffalo rat liver coculture cells express specific growth factors. These results support the theory that coculture systems may enhance pre-embryo growth via the production of embryotrophic factors. The identification of these ligands may provide the rationale for selecting specific growth factors for media supplementation as well as contribute to our understanding of the general mechanisms involved in regulating early embryonic growth and development.

Modulation of leukemia inhibitory factor gene expression and protein biosynthesis in the human fallopian tube

OBJECTIVE

The fallopian tube is the site of fertilization and early embryonic growth and a common site of ectopic implantation. Although the factors responsible for early embryogenesis and implantation are incompletely understood, leukemia inhibitory factor may have an important role in early embryonic development and implantation. We set out to evaluate the production and modulation of leukemia inhibitory factor in the fallopian tube.

STUDY DESIGN

We first investigated leukemia inhibitory factor messenger ribonucleic acid levels in fallopian tubes. We then investigated leukemia inhibitory factor messenger ribonucleic acid and protein production in tubal epithelial and stromal cell cultures.

RESULTS

Leukemia inhibitory factor messenger ribonucleic acid is expressed in the fallopian tube with only slight variation during the menstrual cycle; however, it is markedly elevated in association with ectopic pregnancy. The level is higher in the tubal mucosa than in the remaining layers and is higher in the more distal segments of the fallopian tube. Estradiol and progesterone did not modulate leukemia inhibitory factor expression in epithelial or stromal cell cultures. Interleukin-1 alpha, tumor necrosis factor-alpha, and transforming growth factor-beta enhanced leukemia inhibitory factor expression in epithelial and stromal cells, with transforming growth factor-beta 1 enhancing expression by fourfold in stromal cells. Epithelial cells secreted high levels of leukemia inhibitory factor compared with stromal cells (332 +/- 89 vs 25 +/- 42 pg/mg total protein). Yet stromal cells treated with transforming growth factor-beta alone or in combination with epidermal growth factor and platelet-derived growth factor, as well as TNF-alpha alone or in combination with interleukin-1 alpha enhanced secretion of leukemia inhibitory factor at or above the levels found with epithelial cells.

CONCLUSIONS

We speculate that the high constitutive levels of leukemia inhibitory factor expressed in the ampullary portion of the fallopian tube may play a role in early embryonic development. Additionally, elevated expression with ectopic implantation and the marked induction of secretion in the tubal stroma by growth factors and cytokines suggest a link between inflammation, leukemia inhibitory factor, and tubal ectopic pregnancies.

Coculture with homologous oviductal cells improved the implantation of human embryos--a prospective randomized control trial

PURPOSE

The efficacy of homologous oviductal cell coculture on the success of a human in vitro fertilization program was investigated in a prospective randomized control clinical trial.

METHODS AND RESULTS

One hundred eighty-one couples were randomized into the control and the coculture groups. Pronuclear-stage zygotes were either cultured in Earles' balanced salt solution supplemented with 15% preovulatory serum (control) or cultured with human oviductal cells (coculture) for 24 hr before embryo transfer. There was no difference in the age of the patients, indication for treatment, number of oocyte retrieved or fertilized, or number of embryo replaced between the two groups. The pregnancy rates per transfer for the control and the coculture group were 12.8 and 19.3%, respectively. The number of viable fetus was significantly higher (P < 0.01, chi-square test) in the coculture group (25/264) than in the control group (8/262). The coculture group also showed a higher multiple pregnancy rate, lower abortion rate, and more spare embryos suitable for cryopreservation.

The production of interleukin-1 alpha immunoreactivity by human oviductal cells in a coculture system

PURPOSE

The aim of this study was to determine the concentration of interleukin-1 alpha in human embryo culture medium with or without oviductal cell coculture and to correlate the interleukin-1 alpha levels with pregnancy.

METHODS

Culture media from 32 in vitro fertilization and embryo transfer cycles were assayed for interleukin-1 alpha by immunoassay technique. Human embryos were cultured in Earles' balanced salt solution supplemented with 15% preovulatory serum (sEBSS) in 16 of these cycles, while embryos in the rest of the cycles were cocultured with human oviductal cells in sEBSS.

RESULTS

Both sEBSS and spent sEBSS after embryo culture contained low or undetectable levels of interleukin-1 alpha in the pregnant and nonpregnant cycles. On the other hand, oviductal cells significantly increased the amount of interleukin-1 alpha immunoreactivity in the conventional culture medium or coculture medium (P < 0.001, Mann-Whitney rank sum test). The concentrations of interleukin-1 alpha in the spent sEBSS after oviductal cell culture and after coculture with human embryos were 1.5 +/- 1.0 and 1.3 +/- 0.9 pg/ml, respectively. There was no difference in the interleukin-1 alpha concentration between the pregnant and the nonpregnant coculture cycles.

CONCLUSIONS

These data showed that human oviductal cells produced interleukin-1 alpha immunoreactivity in a coculture system. However, this production could not be used as a marker for successful embryo implantation.

The effects of coculture with autologous cryopreserved endometrial cells on human in vitro fertilization and early embryo morphology: a randomized study

PURPOSE

The aim of this study was to examine the influence of endometrial cells on the fertilization rate and early embryonic morphology following routine in vitro fertilization (IVF). Cryopreservation with subsequent thawing allowed the use of autologous somatic cells, thus minimizing the risk of transmission of infective agents. Interpatient variability was eliminated by randomizing oocytes from each cycle into the control or coculture group.

RESULTS

Two hundred ninety-four oocytes from 24 IVF cycles (21 patients) were included in the study (145 coculture and 149 control). The normal fertilization rate of control oocytes (56.4%) was not significantly different from that of oocytes cocultured with endometrial cells (61.4%). The mean number of blastomeres in cocultured embryos (3.65) was not significantly different from the number in control embryos (3.46) 2 days after insemination, but the proportion of embryos with minimal or no fragmentation was significantly higher in the coculture group [34/84 (40.5%) vs. 17/80 (21.3%); P < 0.01].

CONCLUSIONS

The inclusion of cryopreserved autologous endometrial cells in routine clinical IVF procedures does not influence fertilization or the early cleavage rate but may reduce the extent of embryo fragmentation during the early cleavage divisions.

Optimizing tubal epithelial cell growth promotes mouse embryo hatching in coculture

PURPOSE

This study investigates the relationship between human tubal epithelial cell growth characteristics and mouse embryonic development to determine which cellular requirements should be preferentially provided in a coculture system.

METHODS

Cell growth and viability were assessed for 5 days in alpha-minimal essential medium or human tubal fluid supplemented with 10% human serum or 10% synthetic serum. Two-cell mouse embryo development to blastocyst and hatching blastocyst stages was also assessed with or without coculture.

RESULTS

Both epithelial cell growth and embryo development were dependent on serum supplementation with better cell viability and growth rates in human serum and better blastocyst development in synthetic serum. The highest proportion of hatching blastocysts was found in alpha-minimal essential medium and human serum with coculture.

CONCLUSIONS

Culture conditions which improve tubal epithelial cell growth also improve the hatching rate of mouse embryos in coculture. This indicates that by meeting the metabolic and nutritional demands for epithelial cell growth, the beneficial effects of coculture on embryo development may be optimized.

Potential use of embryo coculture with human in vitro fertilization procedures

PURPOSE

This review was designed to outline potential uses of an embryo co-culture system in human assisted reproduction programs to improve embryo quality and pregnancy rates.

RESULTS

The various cell types used in embryo co-culture were reviewed in addition to the use of co-culture for both animal and human embryos. Co-culture provides a method to enhance embryo development in an inadequate in vitro environment without compromising embryo quality. Human IVF laboratories have used various types of "helper cells" to improve rate of development, reduce cell fragmentation rate and in some instances increases pregnancy and implantation rates.

CONCLUSION

In conjunction with several assisted reproduction procedures such as IVF, microsurgical fertilization, cryopreservation and genetic evaluation, co-culture may increase the number of viable embryos for replacement and improve pregnancy rates.

A human oviduct-specific glycoprotein: synthesis, secretion, and localization during the menstrual cycle

The major objective of this study was to examine the hormonal regulation of a human oviduct-specific glycoprotein (huOGP) throughout the menstrual cycle and in all regions of the human oviduct. Regulation of synthesis and secretion was examined at both the protein (Western immunoblots and immunocytochemistry) and mRNA (Northern and slot blots) levels and correlated with changes in the morphological features of the oviductal epithelial cells throughout the cycle. Immunoblot analysis of oviductal fluid and explant culture media from all regions of the oviduct demonstrated that huOGP is primarily found during the follicular stage of the cycle and is not present in serum, follicular fluid, or uterine endometrium. Moreover, two-dimensional (2-D) immunoblots showed that all major isoelectric variants of huOGP observed on 2-D fluorographs are immunologically related. Light microscopic immunocytochemistry localized huOGP to oviductal secretory cells in both ampulla and isthmic regions, with the most intense immunoperoxidase staining seen in midcycle samples. Using an indirect immunogold technique at the electron microscopic level, huOGP was specifically localized to secretory granules of the ampullary and isthmic nonciliated epithelial cells. The ultrastructural characteristics of these secretory cells during the mid to late follicular phase of the cycle suggested elevated protein synthetic activity. In addition, mRNA expression for huOGP was elevated in all regions of the oviduct in midcycle specimens. Collectively, these data indicate that huOGP is a major tissue-specific, stage-specific secretory product of the human oviduct during the periovulatory stage of the cycle and support the hypothesis that huOGP synthesis and secretion may be regulated by fluctuations in the levels of estrogen and progesterone.

Oviduct during early pregnancy: hormonal regulation and interactions with the fertilized ovum

The cyclic fluctuations in circulating levels of 17 beta-estradiol and progesterone that occur during the menstrual or estrous cycle are responsible for dramatic, cyclic changes in the epithelial lining and secretory status of the mammalian oviduct. The timely transition in the synthesis and release of oviduct proteins, due to the ovarian steroids, and their interactions with oocytes, sperm, and the fertilized ovum underscore key biological events during gamete interactions and early embryonic cleavage. The regulation of these secretory alterations during the first few days of pregnancy is discussed with respect to the influence of the ovarian steroids, their interactions with the embryo microenvironment, and the possible ways in which they may mediate the critical reproductive events of fertilization and embryo development.

EGF, TGF-alpha and EGFR expression in human preimplantation embryos

Epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha) through their common receptor, epidermal growth factor receptor (EGFR) are known to enhance mitogenesis, development and implantation in several species. In the mouse, co-culture of grouped embryos in microdrops increases the cell number and proportion developing to the blastocyst stage. A similar effect is observed with culture of single embryos in medium supplemented with EGF or TGF-alpha highlighting their embryotrophic effects. To study the role of EGF, TGF-alpha and EGFR in early human development, two methods applicable for analysis of expression at the single embryo level have been employed. In the first method, reverse transcription-polymerase chain reaction has been used to examine the presence of transcripts. Following reverse transcription, strategically designed nested primers, optimised for specificity, were used for amplification from the cDNA equivalent of a single embryo. The products were then verified by restriction enzyme digestion and sequence analysis. In the second method, immunocytochemistry has been used to colocalise the expressed proteins. Individual embryos were paraffin embedded and serial sectioned, allowing adjacent sections to be examined with different antibodies and controls. Monoclonal TGF-alpha and polyclonal EGF and EGFR primary antibodies were used. Staining was performed by peroxidase-conjugated avidin-biotin immunocytochemistry with the appropriate controls. The combination of these two methods can potentially be used for simultaneous analysis of several growth factors and/or their receptors in the same human embryos. Transcripts for EGF, TGF-alpha and EGFR were detected in unfertilized oocytes and embryos between 8-cell and blastocyst stages on day 3 to 6 post-insemination.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor, transforming growth factor-alpha, and epidermal growth factor receptor localization in the baboon (Papio anubis) oviduct during steroid treatment and the menstrual cycle

OBJECTIVES

Polypeptide growth factors may modulate the actions of estrogen (E2) and progesterone (P) in reproductive tissues in an autocrine/paracrine manner. The objective of this study was to determine whether the baboon oviduct contains epidermal growth factor (EGF), transforming growth factor-alpha (TGF alpha), and EGF receptor (EGF-R) and whether changes in their expression are correlated with various hormonal states.

METHODS

Oviductal tissue was obtained from adult female baboons (Papio anubis) after oophorectomy and steroid treatment, and during the menstrual cycle. Ampullary regions were fixed in Bouin's fixative and embedded in paraffin for immunocytochemistry using rabbit polyclonal antibodies against EGF and EGF-R, and mouse monoclonal antibody against TGF alpha.

RESULTS

Both EGF and EGF-R were present in all tissue compartments (most strongly in the epithelium, followed by smooth muscle and stroma) at all reproductive stages and showed similar staining patterns. However, the most intense immunoreactive product was found in the tissue obtained from the E2-treated and late follicular phase animals. At this time, intense staining was present in the apical regions of the mature ciliated cells, whereas the stain was dispersed uniformly over the cytoplasm of all other cell types. Immunoreactive TGF alpha was limited primarily to the nonciliated epithelial cells, and staining was most intense in the E2-treated and late follicular phase tissues. Transforming growth factor-alpha formed intense perinuclear deposits in the mature secretory cells, an area that corresponds to the Golgi region. No immunoreactive product was observed for any of these proteins when preimmune serum was substituted for the primary antibody or when the primary antibody was preabsorbed with antigen.

CONCLUSION

In summary, EGF, TGF alpha, and EGF-R are present in the ampulla of the baboon oviduct. Moreover, the localization and intensity of immunoreactive product are dependent on cell type and hormonal state. These data are consistent with the concept that EGF, TGF alpha, and EGF-R may be regulated by E2 and P and thus may play a role in cell differentiation and function. In addition, the specific localization of TGF alpha suggests that this growth factor may be synthesized for release from the secretory cells and thus may also function as a modulator of gamete/embryo viability and development.