A correlative study on the embryotrophic property of patient's serum and the outcome of in vitro fertilization of human oocytes

Use of a medium devoid of any human or animal compound (SMART2) for embryo culture in intracytoplasmic sperm injection

PURPOSE

Our purpose was to evaluate the efficiency of a medium, devoid of any human or animal compound and specially designed for early embryo development (from the zygote to the eight-cell stage), SMART2, in intracytoplasmic sperm injection (ICSI) and to compare it with a medium containing human serum albumin (EllioStep2).

METHODS

Oocytes from 50 ICSI attempts were randomly placed, after sperm injection, into either SMART2 or EllioStep2. After a 48-hr incubation, the embryos were examined for quality scoring before transfer or freezing.

RESULTS

The percentage of normally fertilized oocytes per intact oocytes was slightly higher using SMART2 (139/199 vs. 135/224, respectively, for SMART2 and EllioStep2; P < 0.05). The distribution of embryo scores and the percentage of embryos with a fair morphology (71/143 vs. 72/148, respectively, for SMART2 and EllioStep2; not significant) were identical in both media.

CONCLUSIONS

These data show that SMART2 medium can be successfully used for early embryo growth and, because it is devoid of any human or animal compound, offers better safety for patients than conventional media.

Assessment of the quality of frozen serum by spectrophotometric analysis and sperm bioassay

Serum is an integral part of media used for in vitro fertilization (IVF) and andrology work. Previous studies showed that the IVF results could benefit if sera were screened for deleterious effects before use. Such screening is impractical when fresh sera are used but may be feasible if the serum is frozen prior to use. This study assessed the impact of freezing on the quality of serum. A total of 158 serum samples, prepared in a university-based andrology-IVF center, were included in the study. The frozen sera were thawed in batches to be used in a series of laboratory experiments. Serum quality was evaluated by spectrophotometric analysis and sperm bioassay under several defined conditions: fresh, frozen, pre- and postfiltration, pre- and postcentrifugation, and the patients' fertility condition. Although all sera were filtered through 0.22-micron filter, more than 10% frozen sera required 0.4- or a combination of 0.8- and 0.4-micron filters before they could be passed through the 0.22-micron filter. Frozen sera that were directly filtrable with a 0.22-micron filter lost 13% turbidity upon filtration. The turbidity of the frozen sera were higher compared to fresh ones as revealed by optical density (OD) and relative light scattering (RLS) spectrophotometry. The freeze/storage-induced spectrophotometric changes did not correlate with the storage time. The centrifugation caused precipitation of sera components. The rate of precipitation of the serum components correlated with the duration of freezing. Spectrophotometric analysis and sperm bioassay did not differentiate the sera of pregnancy-positive and pregnancy-negative subjects. The sperm bioassay failed to detect any biological impact of freezing-induced spectrophotometric changes in the sera, suggesting that the freezing-induced changes did not significantly diminish the serum's capability of supplementing the culture media.

A correlation of the outcome of clinical in vitro fertilization with the inositol content and embryotrophic properties of human serum

PURPOSE

This study was designed to investigate whether the level of myo-inositol (MI) in human serum is critical for embryotrophic activity.

METHODS

The embryotrophic properties of human serum were evaluated by the development of postimplantation mouse embryos [in vitro assay of Tam et al. (Fertil Steril 48:834-839, 1987)]. An enzymatic spectrophotometric method using myo-inositol dehydrogenase was used for determination of serum MI. The level of MI detected in serum was compared with the embryotrophic properties and the pregnancy outcome. The effect of MI on the embryotrophic activity of human serum was studied by supplementing the suboptimal serum samples that were unsupportive of embryo growth with extra MI.

RESULTS

Serum obtained from patients having successful IVF pregnancies generally supported better development of postimplantation mouse embryos and contained higher levels of inositol, particularly if the serum sample was collected during the IVF treatment cycle. Serum samples obtained from patients with aborted pregnancies, though supporting mouse embryo development, contained significantly lower concentrations of inositol. An improvement of the embryotrophic properties with exogenous inositol supplement was achieved in some but not all of the suboptimal serum samples studied.

CONCLUSIONS

It is possible that other factors in addition to inositol are crucial in promoting better embryonic development.

Effects of human serum on rat cumulus-oocyte complex functions in vitro: oocyte activation and endocrine secretions

Secretion of hormones and oocyte meiotic events were assessed following in vitro culture of ovulated rat cumulus-oocyte complexes (COCs) in media containing different types of human serum. Both toxic and nontoxic (determined by mouse embryo test) samples of fetal cord or adult female serum were utilized for these experiments. After short-term culture (4.5 hr), with or without COCs, medium containing 10% serum was collected and analyzed for its content of estradiol, progesterone, and prostaglandin E (PGE), and oocytes were cytologically evaluated for spontaneous activation (second polar-body extrusion). Activation of oocytes occurred in all media tested. Steroids (progesterone and estradiol) levels were markedly elevated in culture medium containing cord serum as compared to medium containing adult female serum. The progesterone content of culture medium decreased after incubation of COCs with cord serum and increased when incubated with adult female serum. Little or no prostaglandin was detected in any control media. However, COCs secreted prostaglandin during culture in all media. COCs secreted estradiol when cultured in medium containing cord but not adult female serum. Results demonstrate that two types of serum utilized for in vitro culture of COCs varied markedly in their hormone content and differentially affected the secretion of hormones by COCs during culture. The results are discussed in relation to the success of IVF procedures.

Immunosuppressive activity in human in vitro fertilization (IVF) culture supernatants and prediction of the outcome of embryo transfer: a multicenter trial

The supernatants from cultured human oocytes fertilized in vitro contain low molecular weight factors that can suppress or stimulate the proliferative response of lymphocytes in vitro. The inhibitory and stimulatory effects are nonspecific and may be detected using cultured human or murine tumor cell lines. Using such a bioassay, we previously tested fetal cord serum-supplemented culture supernatant and found that an absence of suppression was correlated with an absence of subsequent pregnancy. To test this association further, additional samples were obtained from four different in vitro fertilization (IVF) units and studied blindly without knowledge of the pregnancy outcome. In this series, samples were obtained after the first 12-24 hr of sperm-oocyte incubation and all of the supernatants were from individual embryo cultures. The average number of preembryos transferred to those achieving pregnancy did not differ significantly from the number transferred to those not achieving pregnancy but the level of suppression was greater (8.7 +/- 1.9%) in those becoming pregnant compared to those not achieving pregnancy (0.8 +/- 1.5%). Twenty-two of 61 patients who received at least one embryo with a suppressive supernatant achieved pregnancy, whereas 0 of 19 patients received embryos lacking suppressive supernatants became pregnant. Two patients who received a single embryo from cultures with suppression became pregnant. Several problems with the bioassay method were defined. The culture medium in this series was always supplemented with adult serum, usually from the patient herself, and this serum could be suppressive.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of human serum as a culture medium for studies of rat embryonic development in vitro

The normal growth of rat embryos cultured in human serum supplemented with glucose and 10% rat serum is of potential use in the assessment of teratogenic risk in man. Before this technique can be widely applied, it is necessary to know whether the stages of the menstrual cycle at which a serum sample is tested materially affect the results obtained. Moreover, in order to achieve reproducible conditions we have found it necessary to add a minimal amount of rat serum to the human serum used for culture, but unnecessarily high levels of rat serum supplementation could over-compensate for any growth factor deficiency in human serum. Here we report that culture of rat conceptuses gives similar results irrespective of whether human first, second, or third trimester pregnancy serum, postnatal serum, or serum at various stages of the menstrual cycle is used. We also report that addition of 2% rat serum supplement is sufficient to achieve reproducible rat embryonic growth and differentiation in human serum.