Pregnancy following in vitro fertilization and embryo transfer using pure human serum as culture and transfer medium

Media composition: macromolecules and embryo growth

Most embryo culture media are still supplemented with proteins rather than with nonprotein macromolecules or recombinant protein products. HSA is probably the most common supplement followed by globulin-enriched preparations. Serum supplementation and Co-Culture of embryos belong to the past. Defined nonprotein or recombinant protein supplements are becoming a viable alternative during gamete and embryo manipulation procedures. Biological protein supplements are still preferred for any extended period of embryo culture. Understanding the goals and purpose of supplemented macromolecules in embryo culture media during each step of the laboratory IVF process should assist us in choosing the safest and most consistent macromolecule for each step, but also selecting a product that has the capability of delivering the best clinical outcome. Each batch of biological protein supplement is unique, even if supplied by the same manufacturer. Each lot of protein supplement typically contains many lot-specific, potentially harmful, and unintended hormone and protein contaminants. Macromolecular embryo culture medium supplements should be identified as one of the highest risk factors in an IVF laboratory that may contribute towards clinical compromise. All efforts should be made to use a proven batch of supplement for as long as the expiration date will allow. The beneficial effect of more complex protein supplements is evident after the activation of the embryonic genome and probably due to the presence of growth factors. Lower live-birth rates due to suboptimum protein supplementation may be a direct result of the preferential loss of female embryos. When deciding on a culture system, thought should be given specifically to the interaction between the culture medium and the macromolecular supplement. Ready-to-use pre-supplemented culture media may be advisable over a more complex product if a comprehensive macromolecular quality management program is not feasible. However, the question remains as to whether the increasing simplification of embryo culture media supplements is ready for large-scale clinical use.

Protein supplementation of human IVF culture media

This review travels the road of protein supplementation in embryo culture development-from whole crude plasma in the mid Twentieth century moving through to the completely genetically engineered human albumin with successful births at the beginning of the Twenty-first.

Synthetic serum substitute (SSS): a globulin-enriched protein supplement for human embryo culture

OBJECTIVE

The purpose of the present study was to evaluate whether an IVF protein supplement prepared from human serum albumin (HSA) and human globulins would retain performance characteristics equivalent to those reported for the commercial plasma expanders, Plasmatein (Alpha Therapeutics, Los Angeles, California) and Plasmanate (Cutter Biological, Miles Inc., Elkhart, Indiana).

METHODS

Pronuclear-stage human embryos were randomly divided and cultured in human tubal fluid medium (HTF) supplemented with either HSA (5 mg/mL) or Plasmatein (10%, v/v; 5 mg/ml) as a means of indirectly assessing the effect alpha- and beta-globulins have on embryonic development. Those results coupled with the known composition characteristics of Plasmatein were used as the starting basis to formulate test lots of synthetic serum substitute (SSS).

RESULTS

Significantly (P < 0.05) more of the human embryos cultured in Plasmatein supplemented medium reached the four-cell or greater stage by 40 hr postinsemination than a comparable group cultured in HSA alone. Lot 1 of SSS, formulated with HSA (84% of total protein) and human globulins (16% of total protein) and an aqueous lipoprotein fraction derived from human plasma (Excyte IV; Miles Diagnostics, Kankakee, Illinois), produced accelerated early embryonic growth relative to control murine embryos grown in the presence of Plasmatein, however, the percentage of the embryos reaching the hatched blastocyst stage was decreased (45 vs 100%). Human embryos from seven patients, randomized to HTF medium supplemented with Plasmatein or lot 1 of SSS, showed equivalent growth at 36-40 hr postinsemination. A microprecipitate developed in media supplemented with lot 1 after several days of culture. The Excyte IV concentration was reduced and, ultimately, eliminated from the subsequent and final prototype lots of SSS. Murine embryos grown in the presence of lipoprotein free SSS showed significantly accelerated (P < 0.01) growth at 17 hr postthaw compared to Plasmatein and all embryos progressed to hatching by 41 hr. Human embryos, randomized to either Plasmatein or lot 3 of SSS, showed significantly accelerated growth (P < 0.01) when scored at 38 hr following insemination.

CONCLUSION

Synthetic serum substitute provides a convient, standardized means of adding protein to media used in assisted reproductive technology (ART) procedures.

Effects of human serum supplementation on fertilization and development of mouse embryos

Serum is generally used as a protein supplement in culture media for human in vitro fertilization (IVF). To determine the effects of serum supplementation on the development of preimplantation embryos, one-cell and two-cell mouse embryos fertilized in vitro and in vivo were cultured in BWW medium supplemented with preovulatory patient serum (PS), human fetal cord serum (HCS), or bovine serum albumin (BSA). The rates of fertilization and development of embryos fertilized in vitro and in vivo were suppressed when the embryos were cultured with PS or HCS as compared with BSA. In the medium supplemented with HCS, growth of in vitro fertilized embryos was retarded at an earlier embryonic stage than was the case with embryos fertilized in vivo. These results suggest that the in vitro fertilized embryo culture model is more sensitive to culture conditions than is the in vivo fertilized embryo culture model. Incorporations of [3H]uridine and [3H]leucine were measured using embryos that developed to the blastocyst stage in a medium supplemented with HCS or BSA. Blastocysts cultured with HCS showed significantly higher incorporations of [3H]uridine and [3H]leucine than those cultured with BSA. While serum supplementation in culture media has adverse effects on embryo cleavage, it augments synthesis of RNA and protein.

Plasmanate as a medium supplement for in vitro fertilization

PURPOSE

The purpose of this study was to evaluate the use of Plasmanate, a protein preparation containing human serum albumin and mixed globulins to autologous preovulatory maternal serum, as an in vitro fertilization (IVF) medium supplement. Plasmanate was used most often in cases involving unexplained infertility, sperm antibodies, and endometriosis or when serum was unavailable.

RESULTS

In a retrospective analysis of 1019 consecutive IVF cycles, Plasmanate was used as the protein supplement to the fertilization medium in 28.6% and maternal serum was used in 71.4% of the attempts. Attempting to eliminate the effects of different medium lots and laboratory conditions, 450 matched patient cycles were compared using the two protein supplements. Finally, the effects of Plasmanate versus maternal serum were compared in prospective randomized trial on patients diagnosed with tubal infertility who were attempting IVF for the first time. The clinical pregnancy rate was 34% for the Plasmanate group versus 24% for those using maternal serum in the retrospective investigation. However, this trend was reversed in the prospective trial.

CONCLUSION

Although further investigation is necessary, it appears that Plasmanate is an appropriate protein substitute in patient cases where serum is absent or unsuitable.

Improved pronuclear mouse embryo development over an extended pH range in Ham's F-10 medium without protein

Pronuclear mouse embryos were cultured at four different pHs (7.17, 7.27, 7.37, and 7.50) in Ham's F-10 medium (Gibco, Grand Island, NY) alone and in Ham's F-10 medium supplemented with 10% human cord serum (v/v) to assess the effects of pH and serum on preimplantation embryo development. Media used in these experiments was stored both without (old protocol) or with triple gas equilibration (new protocol). Development was assessed by the percent of embryos developing to the 2-cell stage and on to the morula and blastocyst stages. Triple gas equilibration prior to media storage improved development to the morula and blastocyst stages. Development to the 2-cell and morula stages was not adversely affected by the presence of serum, but development to the blastocyst stage was significantly higher in Ham's F-10 medium without serum at all pHs tested. In conditions without serum, percent development at all stages examined was similar over the pH range of 7.17 to 7.37, with a significant decrease in development to the morula and blastocyst stage at pH 7.50. Embryos cultured in the presence of serum demonstrated a greater decrease in the percent development to blastocyst at both the low, 7.17 and 7.27, and high, 7.50, pHs, with an apparent pH optimum at 7.37. In summary, the complex media Ham's F-10 medium supports mouse embryo development without the need for serum. Serum inhibits pronuclear embryo development to the blastocyst stage. Mouse embryo culture in the absence of serum can tolerate a pH as low as 7.17 (8.4% CO2) without any detrimental effects.

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.

Randomized trial of two media used for in vitro fertilization

Culture media are important components of IVF. Their selection must meet the need for efficiency, and also economic and practical requirements. From these standpoints, we compared two widely used media: Ham's F10 supplemented with cord serum and Menezo B2 used without serum. The test followed a randomized protocol using two series of 159 and 162 oocytes. Since no difference was seen in efficiency assessed from cleavage rate, the discussion focuses on cost and ease of use.

The effect of serum fractions on single-cell mouse embryos in vitro

To examine the effect of various fractions of human fetal cord serum (HCS) on mouse embryos cultured in vitro, heat-inactivated HCS was separated by ultrafiltration into five distinct fractions: Fractions A, MW greater than 30,000; B, MW 30,000-10,000; C, MW 10,000-5,000; D, MW 5,000-1,000; and E, MW less than 1,000. Seven hundred twenty-eight single-cell embryos were cultured in TYH-280 medium supplemented with 8 mg/ml bovine serum albumin (BSA) and a 20% concentration of Fraction A, B, C, D, or E, whole HCS, or BSA alone. Embryos cultured with Fraction A or E or whole HCS demonstrated a significantly reduced growth rate (P less than 0.01), while embryos cultured with Fraction D demonstrated a significantly increased growth rate (P less than 0.01). Additionally, 649 single-cell embryos were cultured in medium which was supplemented with 8 mg BSA/ml and a 0, 1, 2, or 5% concentration of Fraction A or E. Fraction E displayed toxicity even at a 1% concentration (P less than 0.01), while Fraction A demonstrated growth inhibition at a 5% concentration (P less than 0.05) but increased the hatching rate at a 1% concentration (P less than 0.01). Finally, 635 single-cell embryos were cultured with four distinct fractions of HCS obtained from a Sephacryl S-200 column: Fractions I, MW 100,000; II, MW 70,000-100,000; III, MW 30,000-70,000; and IV, low molecular weight (less than 5,000).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of protein supplementation on single-cell mouse embryos in vitro

For determination of the effect of protein supplementation on single-cell mouse embryos in vitro, 842 single-cell embryos were cultured initially in protein-free medium for variable periods of time and then transferred to bovine serum albumin (BSA)-supplemented medium. The embryos cultured for 24 hours or longer in protein-free medium demonstrated significantly reduced growth rates. An additional 770 embryos were cultured in BSA-supplemented medium initially and then transferred to human fetal cord serum (HCS)-supplemented medium. Significantly reduced growth rates were observed when transfer from BSA to HCS occurred at 48 hours or earlier, and an increased hatching rate was seen if culture in BSA-supplemented medium continued for up to 57 hours. Another 492 embryos were cultured in HCS-supplemented medium and then transferred to BSA. Significantly reduced growth rates were observed when the transfer occurred at 24 hours or later. HCS was then separated by ultrafiltration (10,000 mol wt cutoff), and 1109 embryos were cultured in the media with BSA, whole HCS, small molecular weight fraction (SMCS), or large molecular weight fraction (LMCS) of HCS or BSA and SMCS. The embryos cultured with SMCS demonstrated a significantly reduced growth rate even if BSA was added in the medium. In summary, it appears that the type and timing of protein supplementation of the culture medium is important to embryo growth. Moreover, it seems that serum contains properties that may even be toxic to embryo survival in vitro.

The use of synthetic culture medium and patient serum for human in vitro fertilization and embryo replacement

The use of heat-inactivated patient serum as both fertilization and embryo replacement medium was compared in a prospective randomized study with a fully synthetic culture medium containing human serum albumin without serum addition (B3 INRA Menezo). Another series of the author's IVF program was analyzed retrospectively when a commercially available synthetic medium with bovine serum albumin (B2 INRA Menezo) or B3, as mentioned above, was used without serum addition for fertilization but with 50-100% patient serum as embryo replacement medium. Fertilization rates were significantly higher in the synthetic culture media (70%) than in serum (57%). The rate of polyploid fertilization was significantly lowest in B3 medium. There was a clear trend toward better pregnancy rates when high-percentage or 100% patient serum was used for embryo replacement, no matter if one, two, three, four or more embryos were replaced. We conclude that there should be no need for any kind of serum addition to fertilization media. The present study proves our previous observation that the use of serum seems to be beneficial as embryo replacement medium. This might well be explained by a "protein stick effect" due to the high macromolecular contents of serum rather than by viscosity measurements, since no significant increase in viscosity was observed when a high percentage of serum was added to culture media.

Effect of serum source on human fertilization and embryonic growth parameters in vitro

A total of 100 mature oocytes from 13 consecutive patients were randomly assigned from each patient to one of two treatment groups (n = 53 for group 1, n = 47 for group 2). Group 1 oocytes were incubated throughout the culture periods in medium supplemented with 7.5% homologous patient serum. Group 2 oocytes were treated similarly, except the serum supplement was of fetal cord origin. End points for examination included fertilization frequency, normality of fertilization, stage of embryonic development at two time periods, and quality of embryonic development at two time periods. None of the end points examined revealed significant differences between patient serum and fetal cord serum.