PreImplantation Factor (PIF) correlates with early mammalian embryo development-bovine and murine models.

BACKGROUND: PreImplantation Factor (PIF), a novel peptide secreted by viable embryos is essential for pregnancy: PIF modulates local immunity, promotes decidual pro-adhesion molecules and enhances trophoblast invasion. To determine the role of PIF in post-fertilization embryo development, we measured the peptide's concentration in the culture medium and tested endogenous PIF's potential trophic effects and direct interaction with the embryo. METHODS: Determine PIF levels in culture medium of multiple mouse and single bovine embryos cultured up to the blastocyst stage using PIF-ELISA. Examine the inhibitory effects of anti-PIF-monoclonal antibody (mAb) added to medium on cultured mouse embryos development. Test FITC-PIF uptake by cultured bovine blastocysts using fluorescent microscopy. RESULTS: PIF levels in mouse embryo culture medium significantly increased from the morula to the blastocyst stage (ANOVA, P = 0.01). In contrast, atretic embryos medium was similar to the medium only control. Detectable - though low - PIF levels were secreted already by 2-cell stage mouse embryos. In single bovine IVF-derived embryos, PIF levels in medium at day 3 of culture were higher than non-cleaving embryos (control) (P = 0.01) and at day 7 were higher than day 3 (P = 0.03). In non-cleaving embryos culture medium was similar to medium alone (control). Anti-PIF-mAb added to mouse embryo cultures lowered blastocyst formation rate 3-fold in a dose-dependent manner (2-way contingency table, multiple groups, X2; P = 0.01) as compared with non-specific mouse mAb, and medium alone, control. FITC-PIF was taken-up by cultured bovine blastocysts, but not by scrambled FITC-PIF (control). CONCLUSIONS: PIF is an early embryo viability marker that has a direct supportive role on embryo development in culture. PIF-ELISA use to assess IVF embryo quality prior to transfer is warranted. Overall, our data supports PIF's endogenous self sustaining role in embryo development and the utility of PIF- ELISA to detect viable embryos in a non-invasive manner.

The association of Apoprotein E polymorphisms with recurrent pregnancy loss.

PROBLEM: We have previously reported the role of polymorphisms of thrombogenic genes involved in coagulation and fibrinolysis as risk factors for recurrent pregnancy loss. Thrombophilia has been viewed as a multigenic disorder rather than a monogenetic clinical phenotype and Apo E has been shown to play an important role in lipid metabolism in pregnancy. As individuals carrying the E4 allele of the ApoE gene have the highest risk for thrombosis, we evaluated the frequency of the Apo E4 genotype among women suffering from recurrent pregnancy loss. METHOD OF STUDY: Buccal swabs were obtained from 69 women with a history of two or more consecutive spontaneous abortions and 37 women with at least two live births and not more than one miscarriage. DNA was extracted from the buccal swabs and PCR amplification of Apo E2, E3, and E4 was performed. RESULTS: Women experiencing recurrent pregnancy loss had a significantly higher prevalence of Apo E3/4, E4/4 genotypes (21.7%) compared with control women (5.4%) (P = 0.036). CONCLUSION: Apo E4 polymorphism may contribute to the thrombophilic risk factors contributing to recurrent pregnancy loss.

Are polymorphisms in the ACE and PAI-1 genes associated with recurrent spontaneous miscarriages?

PROBLEM: To determine whether the ACE D/D genotype or the combination of PAI-1 4G/4G and ACE D/D genotypes may serve as a risk factor for recurrent pregnancy loss. METHOD OF STUDY: Buccal swabs were obtained from 120 women experiencing recurrent pregnancy loss and from 84 fertile control women. DNA was extracted from the buccal swab samples using the Qiagen DNA Mini Kit (Qiagen), followed by multiplex polymerase chain reaction (PCR). PCR products were analyzed for the ACE gene polymorphism, which consists of the insertion or deletion (I/D) of a 287-bp fragment in intron 16, and the PAI-1 4G/4G genotype. RESULTS: No significant differences in specific ACE gene mutations were observed when patients experiencing recurrent miscarriage were compared with control women. When the frequencies of homozygous mutations for ACE D/D and PAI-I 4G/4G were compared between recurrent aborters and controls, again no significant differences in the prevalence of the combination of these gene mutations were noted. CONCLUSION: Homozygosity for the D allele of the ACE gene and the combination of the D/D genotype with two 4G alleles of the PAI-1 promoter gene are not associated with a significant increase in the risk of recurrent miscarriage.