Identification of Single Nucleotide Polymorphisms as Biomarkers for Recurrent Pregnancy Loss in Korean Women.

BACKGROUND: Single nucleotide polymorphisms (SNPs) are reportedly associated with repeated abortion. Thus, genetic analysis based on race is the key to developing accurate diagnostic tests. This study analyzed the genetic polymorphisms of recurrent pregnancy loss (RPL) patients among Korean women compared to the controls. METHODS: In 53 women of RPL group and 50 controls, the genetic analysis was performed. The genotype distribution and allele frequency were analyzed statistically for the difference between the two groups. The association between each SNP marker and RPL risk was analyzed. RESULTS: The genotypes of LEPR, endothelial nitric oxide synthase (eNOS), KDR, miR-27a, miR-449b, and tumor necrosis factor-alpha (TNF-α) were analyzed using odds ratio (OR) with 95% confidence intervals (CIs). Only the AG genotype of miR-449b (A>G) polymorphism showed significant association with the risk of RPL when compared to the AA genotype (OR, 2.39). The combination of GG/AG+GG/CA+AA genotypes for eNOS/miR-449b/TNF-α was associated with 7.36-fold higher risk of RPL (OR, 7.36). The GG/AG+GG combination for eNOS/miR-449b showed 2.43-fold higher risk for RPL (OR, 2.43). The combination of AG+GG/CA+AA genotypes for miR-449b/TNF-α showed a significant association with the risk of RPL (OR, 7.60). From the haplotype-based analysis, the G-G-A haplotype of eNOS/miR-449b/TNF-α and the G-A haplotype of miR-449b/TNF-α were associated with increased risk of RPL (OR, 19.31; OR, 22.08, respectively). CONCLUSION: There is a significant association between the risk of RPL and miR-449b/TNF-α combination, and therefore, genetic analysis for specific combined genotypes can be an important screening method for RPL in Korean women.

Successful in Vitro Fertilization and Embryo Transfer after Transplantation of Cryopreserved Ovarian Tissue: Report of the First Korean Case.

For patients at risk of premature ovarian failure with cancer treatment, it is an important option to re-implant the ovarian tissue (OT) after cryopreservation to preserve endocrine function and fertility. With this technique, about 30% of pregnancy success rate and about 90 live births have been reported to date. However, there has been no case report of successful in vitro fertilization (IVF) and embryo transfer (ET) with oocytes collected from transplanted cryopreserved OT in Korea. We report a 30-year old woman with rectal cancer who underwent IVF and ET after cryopreserved OT thawing and re-implantation. She has been diagnosed with stage IIIC rectal cancer after surgery, and right ovary was removed and cryopreserved between cycles of chemotherapy. After completion of chemotherapy and radiotherapy, the patient underwent orthotopic transplantation of cryopreserved OTs. Three months after transplantation, the serum follicle-stimulating hormone level decreased from 91.11 mIU/mL to 43.69 mIU/mL. Thereafter, the patient underwent 11 ovarian stimulation cycles, and in 7 cycles, follicle growth was observed at the OT graft site. In one of these cycles, the oocyte was successfully retrieved and one embryo was transplanted after IVF. The patient was not pregnant, but the cryopreservation of OT can save the fertility after anticancer chemotherapy.

Prolactin receptor gene polymorphism and the risk of recurrent pregnancy loss: a case-control study.

Since the first study was published reporting the candidate association between the prolactin receptor gene intron C/T polymorphism (rs37389) and recurrent miscarriage, no replication study has been performed. In this study, we investigated the role of the prolactin receptor gene C/T polymorphism in 311 Korean women with recurrent pregnancy loss and 314 controls. Genotyping for prolactin receptor gene intron C/T polymorphism was performed using a TaqMan assay. The significance of difference in the genotype distribution was assessed using a chi-square test, and continuous variables were compared using a Student's t-test. The genotype distribution of the prolactin receptor gene C/T polymorphism in the recurrent pregnancy loss group did not differ from that in the control group (CC/CT/TT rates were 49.8%/41.5%/8.7% and 52.5%/37.6%/9.9% for the recurrent pregnancy loss patient and control groups, respectively, p = .587). When the analysis was restricted to patients with three or more consecutive spontaneous miscarriages or patients without prior live birth, there were also no differences in the genotype distribution between these subgroups and controls. In conclusion, the findings of the current study suggest that the prolactin receptor gene intron C/T polymorphism is not a major determinant of the development of recurrent pregnancy loss. Impact statement What is already known: Many studies have investigated whether there is a genetic component for the risk of recurrent pregnancy loss. Recently, one study investigated whether genetic polymorphisms involved in the regulation of the hypothalamic-pituitary-ovarian axis would be associated with recurrent miscarriage. Among 35 polymorphisms in 20 candidate genes, genotype distribution with regard to the prolactin receptor gene intron C/T polymorphism (rs37389) differed between the recurrent miscarriage and the control groups. Since this study reporting the candidate association between the prolactin receptor gene and recurrent miscarriage, no replication study has been performed. What the results of this study add: The genotype distribution of the prolactin receptor gene C/T polymorphism in the recurrent miscarriage group did not differ from that in the control group. What the implications are of these findings: Our study may be useful in that it is the first replication study since the initial report of the association of prolactin receptor gene polymorphism with recurrent miscarriage. Although no association was found, the potential role of prolactin in pregnancy loss needs to be further investigated because prolactin and its receptor have been postulated to play an important role in the maintenance of normal pregnancy.

Methylenetetrahydrofolate Reductase Polymorphisms and Risk of Recurrent Pregnancy Loss: a Case-Control Study.

The balance between coagulation and fibrinolysis is an essential part in early pregnancy. Mutations in methylenetetrahydrofolate reductase (MTHFR) gene lead to decreased activity of the enzyme and hyperhomocysteinemia, which then induces platelet aggregation by promoting endothelial oxidative damage, possibly resulting in adverse effect on maintenance of pregnancy. We investigated the role of MTHFR single nucleotide polymorphisms (SNPs), C677T and A1298C, in Korean patients with recurrent pregnancy loss (RPL). We conducted a prospective case-control study in the Korean population. Subjects included 302 women with 2 or more consecutive, unexplained, spontaneous miscarriages before 20 weeks of gestation and 315 control women without a history of recurrent miscarriages. The genotyping for C677T and A1298C polymorphisms was performed using the TaqMan assay. Continuous variables were compared using Student's t-test, and χ² test was used to evaluate differences in the genotype distributions between the RPL and the controls. The genotype distribution of both polymorphisms in the RPL group did not differ from those of the controls. For further analysis, if RPL patients were divided according to the numbers of pregnancy losses (≥ 2 and ≥ 3) neither group was significantly different compared with controls. MTHFR gene C677T and A1298C polymorphisms are not associated with idiopathic RPL in Korean women, suggesting that those may not be susceptible allelic variants or be deficient to cause RPL.

Estrogen receptor beta gene polymorphisms and risk of recurrent pregnancy loss: a case-control study.

Estrogen might play a key role in the maintenance of pregnancy. We investigated the role of the ER-ß gene +1730 G/A, +1082 G/A, and CA repeat polymorphisms in Korean patients with recurrent pregnancy loss (RPL). Genotyping was performed using the TaqMan assay in 305 patients with at least two unexplained consecutive spontaneous miscarriages before 20 weeks of gestation and 299 controls. The genotype distributions of the ER-ß gene +1082 G/A and +1730 G/A polymorphisms in the RPL group did not differ from those in the control group. When the analysis was restricted to patients with three or more consecutive spontaneous miscarriages, there were also no differences in the genotype distribution between this subgroup and controls. The number of CA repeats was distributed from 13 to 28 with two large peaks at 18 and 23 in patients with RPL and controls. Using the two major peaks as cut-offs, the allele distributions were compared between patients and controls. However, the distribution of ER-ß gene CA repeats did not differ between women with recurrent miscarriage and controls. Findings of the current study suggest that the ER-ß gene polymorphisms are not major determinants of the development of RPL in Korean women.

Fas and FasL genetic polymorphisms in women with recurrent pregnancy loss: a case-control study.

Aberrant apoptosis at the trophoblast-maternal interface and abnormal expression of Fas and Fas ligand (FasL) have been reported in complicated pregnancies with recurrent pregnancy losses (RPL) and preeclampsia. We assessed the prevalence of Fas and FasL genetic polymorphisms in Korean women with RPL and in fertile controls. In total, 306 women with RPL and 298 fertile controls were enrolled. Genotype distributions of Fas and FasL in RPL patients versus fertile controls were examined under the Hardy-Weinberg equilibrium. Fas -670 A/G genotype (AA versus AG versus GG, p = 0.340) and allele frequencies (A versus G, p = 0.412) were not different between the RPL and control groups. There was no difference in each Fas -1377 G/A and FasL -844 C/T genotype, and their allele frequencies. In addition, the unions of two zygosities of each genotype and their combined genotypes did not differ between two groups. No difference in the prevalence of Fas and FasL single-nucleotide polymorphisms (SNPs) was observed between women with RPL and fertile controls among Korean women. To determine the possibility of genetic polymorphisms in Fas and its ligand as risk factors for RPL, further studies in various races and a large study population are needed.

No association of p53 codon 72 polymorphism with idiopathic recurrent pregnancy loss in Korean population.

OBJECTIVE: The balance of apoptosis and proliferation is an important part in the embryonic development during pregnancy. It has been reported that the p53 gene plays a significant role in angiogenesis and placental development, namely in reproduction and is suggested as a potential mediator of pregnancy. This study was performed to investigate whether the genetic polymorphism of the p53 gene is associated with idiopathic recurrent pregnancy loss (RPL). STUDY DESIGN: We conducted a case-control study in the Korean population. Study subjects consisted of 294 patients with idiopathic RPL and 300 postmenopausal controls. The genotyping for the p53 codon 72 polymorphism was performed using a Taqman assay. Continuous variables were compared using Student's t test and the χ(2) test was used to evaluate differences in the genotype distributions between the RPL and the controls. RESULTS: There were no significant differences in the genotype distributions or allele frequencies of the p53 codon 72 polymorphism between the RPL and control group. There was also no significant association between the p53 codon 72 polymorphism and RPL risk in both recessive (Pro/Pro vs. Arg-carriers, p=0.314) and dominant model (Pro-carriers vs. Arg/Arg, p=0.383: data not shown). CONCLUSION: The codon 72 polymorphism in the p53 gene did not show any correlation with idiopathic RPL in Korean women, implying that it may not be susceptible allelic variants or be insufficient to cause RPL.

The PAI-1 4G/5G and ACE I/D polymorphisms and risk of recurrent pregnancy loss: a case-control study.

PROBLEM: Thrombophilia has been postulated to be a contributor to the pathophysiology of recurrent pregnancy loss (RPL). We investigated the role of the plasminogen activator inhibitor type 1 (PAI-1) 4G/5G and angiotensin converting enzyme (ACE) I/D polymorphisms in Korean patients with RPL. METHOD OF STUDY: Genotyping was performed using the TaqMan assay in 227 RPL patients and 304 controls. RESULTS: The genotype distributions of both polymorphisms in the RPL group did not differ from those of controls. Because the frequency of being homozygous for ACE D/D and the PAI-I 4G/4G combination has been reported to be significantly higher in RPL patients, this was also analyzed. However, no significant difference was noted; 3.1% of RPL patients had both ACE D/D and PAI-I 4G/4G, as did 4.9% of controls (P = 0.791). CONCLUSION: The current study suggests that both polymorphisms, either alone or in combination, are not major determinants of the development of RPL in Korean women.

Establishment of stem cell lines from nuclear transferred and parthenogenetically activated mouse oocytes for therapeutic cloning.

OBJECTIVE: To establish embryonic stem cell lines from nuclear transfer of somatic cell nuclei isolated from the same oocyte donor and from parthenogenetic activation. The study also evaluated the effect of the micromanipulation procedure on the outcome of somatic cell nuclear transfer in mice. DESIGN: Randomized, prospective study. SETTING: Hospital-based assisted reproductive technology laboratory. ANIMAL(S): F(1) (C57BL/6 x 129P3/J) mice. INTERVENTION(S): Metaphase II-stage oocytes were either parthenogenetically activated or nuclear transferred with cumulus cell nuclei or parthenogenetically activated after a sham-manipulation procedure. MAIN OUTCOME MEASURE(S): Embryogenesis and embryonic stem cell establishment. RESULT(S): The development rate to morula/blastocyst of nuclear transferred oocytes (27.9% +/- 5.9%) was significantly lower than that of the sham-manipulated (84.1% +/- 5.6%) or parthenogenetic (98.6% +/- 1.4%) groups. A sharp decrease in cleavage potential was obvious in the two- to four-cell transition for the nuclear transferred embryos (79.0% +/- 4.6% and 43.3% +/- 5.0%), implying incomplete nuclear reprogramming in arrested oocytes. However, the cleavage, as well as the development rate, of parthenogenetic and sham-manipulated groups did not differ significantly. The embryonic stem cell line establishment rate was higher from parthenogenetically activated oocytes (15.7%) than nuclear transferred (4.3%) or sham-manipulated oocytes (12.5%). Cell colonies from all groups displayed typical morphology of mice embryonic stem cells and could be maintained successfully with undifferentiated morphology after continuous proliferation for more than 120 passages still maintaining normal karyotype. All these cells were positive for mice embryonic stem cell markers such as Oct-4 and SSEA-1 based on immunocytochemistry and reverse transcriptase-polymerase chain reaction. The clonal origin of the ntES cell line and the parthenogenetic embryonic stem cell lines were confirmed by polymerase chain reaction analysis of the polymorphic markers. Blastocyst injection experiments demonstrated that these lines contributed to resulting chimeras and are germ-line competent. CONCLUSION(S): We report the establishment of ntES cell lines from somatic cells isolated from same individual. Our data also suggest that embryo micromanipulation procedure during the nuclear transfer procedure influences the developmental ability and embryonic stem cell establishment rate of nuclear transferred embryos.