Evaluation of serum-associated embryotoxicity in women with reproductive disorders

SPERM APOPTOSIS IN NONPREGNANT LUTEALPHASE SERA AFTER IN VITRO FERTILIZATION AS ASSESSED BY COMPARATIVE GENOMIC HYBRIDIZATION

Toxicity in serum has been reported in cases of recurrent spontaneous abortions and endometriosis. The null hypothesis was that serum toxicity was not involved in failed pregnancies after in vitro fertilization procedures. The objective was to expose donor sperm to pregnant versus nonpregnant patient sera and analyze for sperm DNA damaging effects using a novel comparative genomic hybridization method. Luteal phase sera (N = 21 cases) were drawn one week after embryo transfer. Colloid-washed donor sperm were incubated (48 h, 37 degrees C, 5% CO2 in air) in 0% or 50% sera. Single-stranded DNA (ssDNA) of control sperm were stained in Hoechst 33342 and hybridized to Sybr Gold-stained ssDNA of sera-treated sperm. Image analyses were performed and fluorescent intensities analyzed. Nonpregnant patient sera (57% of cases) were associated with DNA fragmentation (64.4 +/- 8.8 pixels; mean +/- S.E.M.) when compared with pregnant patient sera (106.3 +/- 8.4 pixels). There were no differences in the sera of biochemical (108.2 +/- 15.3) versus clinical pregnancy cases (105.3 +/- 11.4). The results suggest that nonpregnant patient sera contained factor(s) that cause DNA fragmentation leading to pregnancy losses.

Luteal phase serum cell-free DNA as a marker of failed pregnancy after assisted reproductive technology

PURPOSE

DNA-damaging factors have been reported in patients that failed to achieve pregnancy after assisted reproductive technologies (ART). The hypothesis was that increased circulating cell-free DNA released by damaged cells could predict unfavorable conditions leading to failed ART treatment. The objective was to compare the relative concentrations of cell-free DNA in the luteal phase sera of nonpregnant versus pregnant patients.

METHODS

Frozen-thawed sera (30 IVF cases) were obtained 1 week after embryo transfer. There were 16 pregnant and 14 nonpregnant cases and controls consisting of male sera (n = 8 cases). Modified isocratic capillary electrophoresis was performed and the images analyzed for cell-free DNA.

RESULTS

Circulating cell-free DNA were identified in the sera of all patients. The serum concentrations of high (12 kb) and low (1 kb) molecular weight cell-free DNA were similar for both nonpregnant and pregnant patients. Male control sera had higher cell-free DNA concentrations compared with females. Evaluation of sera from a control case showed no fluctuations in cell-free DNA concentrations throughout specific days of the menstrual cycle.

CONCLUSIONS

The results do not support the use of the luteal phase cell-free DNA concentration as a marker for failed pregnancies. The equal concentrations of high and low molecular weight cell-free DNA and ladder band-like gel patterns suggested cell apoptosis as the source of DNA.

Oocyte comet assay of luteal phase sera from nonpregnant patients after assisted reproductive procedures

PURPOSE

Serum factors in patients with recurrent spontaneous abortions (RSA) inhibit mouse embryo development in vitro. Serum factors affecting DNA integrity remain to be tested. The null hypothesis was that patient sera do not affect DNA integrity. The objectives were (a) to use the oocyte comet assay to assess DNA damage after exposure to patient sera and (b) to determine the effect of sera from gravidity 0 parity 0 patients to induce DNA apoptosis.

METHODS

Luteal phase sera were drawn 1 week after embryo transfer following assisted reproductive procedures. Frozen-thawed hamster zona intact oocytes at metaphase II were incubated in groups of eight in either control medium or medium supplemented with 50% patient serum for 1.5 h at 37 degrees C in room air. The oocytes were fixed, stained in acridine orange, embedded in agarose, lysed, and alkaline electrophoresis performed. The intensities of the digitized fluorescent images were analyzed.

RESULTS

The sera of nonpregnant patients (64%) caused significant fragmentation of hamster oocyte DNA when compared with pregnant patient sera. This difference was also observed when adjusted for patient age. Sera of patients that had never been pregnant also resulted in oocyte DNA fragmentation.

CONCLUSIONS

The results suggested that sera from patients that did not conceive contained factors that did not support cell growth by causing DNA fragmentation and apoptosis. The level of the apoptotic factors varied from cycle to cycle. However, more studies are needed to determine if the sera factors actually reach the uterine environment to cause the undesirable effects.