The development of a successful non-university-based ambulatory in vitro fertilization/embryo transfer program: phase I

Superovulation, in vitro fertilization (IVF) and in vitro development (IVD) protocols for inbred BALB/cJ mice in comparison with outbred NMRI mice

Purpose

To study assisted reproductive technology (ART) protocols including superovulation, in vitro fertilization (IVF) and in vitro development (IVD) for BALB/cJ mice in comparison with a common ART protocol for NMRI mice.

Methods

Adult NMRI and BALB/cJ mice were superovulated using a 48 h G-interval. In order to find a more suitable G-interval for the BALB/cJ strain, G-intervals including 44, 46 and 50 h were also examined. Superovulation rates were recorded in all groups. IVF rate of BALB/c oocytes in T6 and mHTF media were compared. IVD rates of BALB/cJ zygotes in mHTF, T6 and G1V₅/G2V₅ media were compared. In addition, IVF and IVD rates of BALB/cJ and NMRI oocytes were compared in T6 medium during IVF-IVD procedures.

Results

In BALB/cJ mice the highest superovulation rates were observed with 44-46 h G-intervals. However, with a 48 h G-interval, superovulation rates were significantly lower in BALB/cJ compared to NMRI mice (p < 0.05). mHTF medium significantly increased in vitro fertilization of BALB/cJ oocytes compared to T6 medium (p < 0.05). Fertilization rate of NMRI oocytes was significantly higher than BALB/cJ oocytes in T6 medium (p < 0.05). The BALB/cJ embryo IVD was significantly higher in G1/G2 medium compared to mHTF and T6 media (p < 0.01).

Conclusions

Superovulation with 48 h G-interval and using T6 during all in vitro procedures produces embryos more efficiently for NMRI mice than for BALB/cJ mice. For BALB/cJ mice, a protocol including superovulation with a 44-46 h G-interval, using mHTF during IVF and G1V₅/G2V₅ medium during IVD, may improve in vitro embryo production.

In vitro fertilization (IVF) of mouse ova in HEPES-buffered culture media

Some major drawbacks of a bicarbonate-buffered culture medium include the requirement of an elaborate incubator system able to maintain a 5% CO2 environment and the inability of the culture medium to maintain a physiological pH range (pH 7.3-7.4) in room air (0.03% CO2). This work resulted in the development of IVF culture media, BB (modified T6) and Hams-HEPES, which use HEPES-buffered systems not requiring the specialized CO2 environment to maintain a physiological pH range in room air. These media generate above-average cleavage rates in in vitro fertilized, superovulated B6CBAF1 mice ova. The effect of heparin and HEPES on cleavage was studied and neither had a significant effect at the concentrations used. Cleavage rates of nonfertilized ova (parthenogenic division) were 9 to 13%. There was no significant difference in parthenogenesis between any of the culture media and it appears to be a function of the strain of mice and the timing between human chorionic gonadotropin (hCG) injection and ovum collection. These results emphasize the need to account for parthenogenesis when determining cleavage rates of in vitro fertilized mouse ova. Also, the results suggest that because of individual mouse differences in cleavage rates, it is important to use an adequate number of mice per group to determine an accurate, average cleavage rate.

Induction of multiple follicular development as a therapy for unexplained or male-related infertility

Most invasive techniques (i.e., in-vitro fertilization, gamete intrafallopian transfer) used for the therapy of unexplained or male-related infertility involve the induction of multiple follicular development (MFD). The efficacy of MFD in conjunction with a non-invasive technique (artificial insemination with husband's semen) was evaluated in a group of 41 couples with long-lasting infertility. MFD was obtained by means of clomiphene citrate and exogenous gonadotropins. Within 6 months of treatment, pregnancy was achieved by 52.2% of couples with male-related infertility and by 54.5% of couples with unexplained infertility. Sperm parameters, age of the female partner and preovulatory estradiol peak did not show any significant difference between couples who conceived and those who did not. It is concluded that induction of MFD represents an effective therapy and might replace invasive techniques for the treatment of the above conditions.

The effect of fibrin sealant on mouse embryos

It is postulated that ovarian hyperstimulation prior to embryo transfer results in changes in the endometrium which lead to poor adhesive properties of the endometrium. Based on the properties of fibrin sealant which is used in human operative medicine, it is believed that adhesion of embryos to the endometrium during embryo transfer may be encouraged by the addition of fibrin sealant. The purpose of this study was to assess the effects of the addition of fibrin sealant to a mouse embryo/Ham's F-10 culture medium mixture. There was no statistical difference in the number of blastocysts developing from 138 embryos in standard medium compared with 139 cultured with the addition of fibrin sealant. It is concluded that fibrin sealant is not embryotoxic, and thus following further experimentation its eventual utilization in human in vitro fertilization/embryo transfer programs appears promising.

Human gene expression first occurs between the four- and eight-cell stages of preimplantation development

The earliest stages of development in most animals, including the few mammalian species that have been investigated, are regulated by maternally inherited information. Dependence on expression of the embryonic genome cannot be detected until the mid two-cell stage in the mouse, the four-cell stage in the pig (J. Osborn & C. Polge, personal communication), and the eight-cell stage in the sheep. Information about the timing of activation of the embryonic genome in the human is of relevance not only to the therapeutic practice of in vitro fertilization and embryo transfer (IVF), but more importantly for the successful development of techniques for the preimplantation diagnosis of certain inherited genetic diseases. We describe here changes in the pattern of polypeptides synthesized during the pre-implantation stages of human development, and demonstrate that some of the major qualitative changes which occur between the four- and eight-cell stages are dependent on transcription. In addition, it appears that cleavage is not sensitive to transcriptional inhibition until after the four-cell stage.

A paired analysis of in vitro fertilization and cleavage rates of first- versus last-recovered preovulatory human oocytes exposed to varying intervals of 100% CO2 pneumoperitoneum and general anesthesia

This study compares the in vitro fertilization and cleavage rates of paired first- and last-recovered preovulatory human oocytes that were exposed to a 100% CO2 pneumoperitoneum and general anesthesia. In 305 consecutive cycles of laparoscopy, 1741 oocytes (5.7/cycle) were recovered. The exact time of aspiration (T) was recorded for each oocyte. The time interval (T1 to T2) between recovery of first and last oocytes ranged from 0 to 38 minutes and represented differences in the exposure time of first and last oocytes to the CO2 pneumoperitoneum and to general anesthesia. For all cycles (n = 305) without regard for T1 to T2, last-recovered oocytes fertilized less often than first-recovered eggs (P = 0.06; McNemar's test). When T1 to T2 was short (less than or equal to 5 minutes), first- and last-recovered oocytes fertilized at comparable rates (70.8% and 74.0%). When only cycles with T1 to T2 greater than 5 minutes were considered (n = 209), the difference in fertilization rates between first and last oocytes (68.5% versus 56.4%) was highly significant (P less than 0.01; McNemar's test). Pairing negated differences due to patient, cycle, or semen variables and first- and last-recovered oocytes had comparable maturity scores (4.0 +/- 0.5 versus 4.3 +/- 0.8). There were no significant differences in cleavage rates for first- and last-recovered oocytes that fertilized, regardless of the exposure interval (T1 to T2). We conclude that exposure to a 100% CO2 pneumoperitoneum and/or general anesthesia may adversely affect oocyte quality.

The effect of preimplantation culture conditions on murine embryo implantation and fetal development

Ham's F-10 medium (Gibco, Grand Island, NY) and medium T6 with and without 15% fetal calf serum (FCS) were compared for their ability to support development of murine blastocysts with the capacity to implant and produce normal fetuses when transferred to pseudopregnant females. All media supported equal rates of blastocyst development from 2-cell embryos. In addition, there were no differences in the rates of blastocyst implantation. However, once implanted, blastocysts grown in T6 produced a significantly higher proportion of normal fetuses (58.5% to 65.9%) than blastocysts grown in either Ham's F-10 (2.4%) or T6 with FCS (27.6%). These results demonstrate that the rate of murine blastocyst development from 2-cell embryos in vitro is not a good criterion of healthy embryos. Murine blastocysts transferred in medium with 0% versus 50% FCS implanted and developed into normal fetuses at equal rates.

Sperm wash in three culture media: maximization of motile sperm recovery during swim-up incubation

Three different culture media commonly used during in vitro gamete manipulations were studied for their efficacy in sperm wash procedure. Highest numbers of motile sperm were recovered at 6 hours following incubation in WT-6 and Ham's F-10 media. However, WT-6 yielded higher motile sperm numbers than Ham's F-10. Swim-up sperm number reached a peak at 3 hours following incubation in BWW. A period of 2 to 6 hours of incubation of sperm pellets overlayed with sperm wash media resulted in highly enriched motile sperm fractions free of dead spermatozoa and seminal debri.

Hormonal parameters in follicular fluid and the fertilization rate of in vitro cultured oocytes

Oocytes and matched samples of follicular fluid were obtained from 52 preovulatory follicles aspirated laparoscopically for in vitro fertilization (IVF). Follicular fluid concentrations of estradiol (E2), progesterone (P), testosterone (T), prolactin (HPRL), prostaglandin F2 alpha (PGF2 alpha), prostaglandin E (PGE), protein content, and collagenolytic activity were measured and related to the fertilization rate of oocytes cultured in vitro. High concentrations of P and low levels of T and HPRL were associated with mature, fertilizable oocytes. Levels of PGF2 alpha, PGE, and follicular fluid protein concentrations were similar in both groups. Mean collagenolytic activity was increased in the fertilized oocytes, although no significant difference could be observed. Our data demonstrate a close association between follicular fluid steroid and HPRL concentrations and successful fertilization of oocytes.

Treatment-independent, treatment-associated, and pregnancies after additional therapy in a program of in vitro fertilization and embryo transfer

Although the technique of in vitro fertilization and embryo transfer (IVF-ET) was developed for couples with untreatable tubal factor infertility, IVF-ET is now being applied to women with other causes of infertility and normal pelvic anatomy. In an effort to determine the treatment-independent pregnancy rate, we retrospectively reviewed the first 245 couples enrolled in the IVF-ET program at Duke University Medical Center. There were 19 treatment-independent pregnancies in 18 women and 3 treatment-associated pregnancies in cycles in which the oocyte retrieval was canceled (in 2 women washed intrauterine insemination was substituted for oocyte retrieval). Six pregnancies were established after an unsuccessful attempt at IVF-ET with additional non-IVF-ET therapy, including washed intrauterine insemination in three couples, and donor insemination in two couples. These observations suggest that a significant number of treatment-independent pregnancies will occur in couples clinically deemed appropriate for IVF-ET, pregnancies can be established in cycles of controlled hyperstimulation without oocyte retrieval, and additional non-IVF-ET therapy can result in pregnancy despite failure of IVF-ET in selected couples.

Influence of water quality on in vitro fertilization and embryo development for the mouse

Mouse in vitro fertilization and embryo culture were performed in media prepared with five different water preparations. The results of the experiments improved with the frequency of distillation. Each water preparation was analyzed by the measurement of the electrical conductivities and inorganic ion concentrations and by high-performance liquid chromatography to examine the mutual relation between water quality and the method of water purification. The best results were obtained with Milli-Q water, which had the lowest concentration of inorganic ions and organic compounds. On the contrary, unexpected contamination by organic compounds and zinc ions occurred after multiple distillation, possibly leached from the glassware and silicon tube. The hatching rate seemed to be an appropriate indicator to assess the biological qualities of media for the development of embryos cultured in vitro.

Antiestrogenic effect of clomiphene citrate in a multiple follicular stimulation protocol

End-organ antiestrogenic effects of clomiphene citrate (CC) have been demonstrated in the female reproductive tract at the levels of the ovary, cervix, and endometrium. However, it has not been established whether this effect is manifested during concomitant human menopausal gonadotropin (hMG) administration, as occurs in hMG/CC stimulations of multiple follicular development. To assess this question a review was made of serum estradiol (E2) and cervical mucus in 47 hMG and 56 hMG/CC stimulations on days -2, -1, 0, and +1 relative to the day of hCG administration. E2 levels (pg/ml) were significantly lower in the hMG as compared to the hMG/CC group. However, comparing the hMG and hMG/CC groups, cervical mucus scores were significantly higher in the former. Furthermore, an analysis of covariance demonstrated that the cervical mucus scores on each day were significantly lower in the hMG/CC group (P less than 0.001). Thus, in hMG/CC stimulations for in vitro fertilization (IVF), despite the concomitant administration of pharmacologic doses of hMG, CC exerts an antiestrogenic effect on at least one end organ, cervical mucus production. Potentially, this antiestrogenic effect in IVF stimulations would be exerted at other female reproductive tract sites including the endometrium; however, its clinical significance, if any, is unclear.

An in vitro fertilization and embryo transfer pilot study: treatment-dependent and treatment-independent pregnancies

A pilot program of in vitro fertilization and embryo transfer at McMaster University is described. Fourteen couples with a clinical diagnosis of infertility due to apparent tubal dysfunction, with evidence of ovulation, and with normal semen analysis underwent induction of superovulation with human menopausal gonadotropin. At laparoscopy, 82 follicles were aspirated and 19 oocytes were recovered. Eleven oocytes demonstrated cleavage and all inseminated oocytes were transferred 49 to 65 1/2 hours after insemination. In vitro fertilization therapy resulted in two pregnancies, one leading to a spontaneous abortion and the other to the birth of a healthy female infant. At 10 to 12 months after in vitro fertilization therapy in the remaining 12 patients, there were three additional pregnancies (treatment-independent), one ectopic and two intrauterine. One patient was delivered of a healthy female infant. In vitro fertilization therapy should be evaluated by a randomized controlled clinical trial.

Optimization of hydrogen-ion concentration during aspiration of oocytes and culture and transfer of embryos

Rapid and marked shifts in pH can have deleterious effects on oocytes and embryos. Such shifts are most likely to occur during laparoscopy and examination of gametes and embryos. We studied the rate of pH change of follicular fluid and bicarbonate- and phosphate-based media during exposure to 100% CO2 with a constant surface area to volume ratio. All solutions tested developed a pH below the physiological range of 7.30-7.50 within 2 min of exposure to 100% CO2. We also examined the rate of increase in pH due to CO2 loss from media in room air within standard organ culture dishes and tubes. After exposure to ambient conditions for 2 min, the pH of modified Ham's F-10 medium in organ culture dishes rose above the physiological range. We have used a needle laparoscope to confirm intraperitoneal placement prior to the insufflation of a 5% CO2 gas mixture for laparoscopic oocyte retrieval. We have carried out all examinations of oocytes and embryos within a pediatric isolette equipped with an automatic CO2 controller to maintain a 5% CO2 environment. We have transferred embryos in 15% fetal cord serum to avoid the alkaline pH associated with a high concentration of equilibrated heat-inactivated preovulatory serum. These simple techniques can optimize the hydrogen-ion concentration of media during the entire process of in vitro fertilization and embryo transfer.

In vitro fertilization. The Scripps Clinic experience

The in vitro fertilization (IVF) program at Scripps Clinic and Research Foundation, La Jolla, California, was started in 1983. In vitro fertilization is now an accepted type of infertility treatment for many couples with a disorder of tubal origin, endometriosis, male-factor infertility, or idiopathic infertility. Successful outcome has depended on the woman's age, the cause of infertility, and the number of embryos transferred. The highest pregnancy rate has been achieved in women under age 35 with tubal-factor infertility and transfer of three or more embryos. During the first year, the program's overall pregnancy rate was 13% (5 pregnancies/38 embryo transfers) and the pregnancy rate for women under age 35 with tubal-factor infertility was 28%. The functioning of an IVF program depends on the availability of a clinical laboratory for daily hormone measurements, ultrasonography for monitoring follicle growth, an operating room that is available any time day or night, and a laboratory equipped for fertilization of retrieved ova and monitoring of embryo development. Clearly, a carefully integrated team of medical care providers is necessary for a program that draws on so many different clinical resources.