What next for preimplantation genetic screening?

Preimplantation genetic diagnosis for aneuploidy screening (preimplantation genetic screening-PGS) has been used to detect chromosomally normal embryos from subfertile patients. The main indications are advanced maternal age (AMA), repeated implantation failure, repeated miscarriages and severe male factor infertility. Many non-randomized PGS studies have been published and report an increase in implantation rate, and/or a decrease in miscarriage rate. Recently, two randomized controlled trials have been conducted on patients with AMA as the only indication. Neither study showed a benefit in performing PGS using live birth rate as the measure of success. The debate on the usefulness of PGS is ongoing; the only effective way to resolve the debate is to perform more well-designed and well-executed randomized clinical trials.

Impact of chromosomal abnormalities on preimplantation embryo development.

OBJECTIVES: To evaluate the influence of numerical chromosomal abnormalities on preimplantation embryo development. METHODS: This study includes 6936 embryos from 1245 women undergoing preimplantation genetic diagnosis (PGD). Indications for aneuploidy screening were: recurrent miscarriages, implantation failure, severe male factor, advanced maternal age, and mixed causes. Embryo biopsy was performed on day 3, and embryos were co-cultured until day 5, when embryo transfer was performed. RESULTS: In the aneuploidy screening regimen, normal euploid embryos showed significantly higher blastocyst rates (68.2%) compared to chromosomally abnormal (42.8%, p < 0.0001) and mosaic (53.7%, p < 0.0001) embryos. Among aneuploid embryos for autosomes, higher blastocyst rates were observed in trisomies than monosomies, although only statistically significant in patients over 36 years of age (50.8 vs 38.9%; p < 0.0001). In contrast, in embryos with sex chromosomes aneuploidy, similar blastocyst rates were observed between trisomies and monosomy X. CONCLUSION: Embryos with certain types of chromosomal abnormalities were negatively selected during preimplantation embryo development. Despite this selection, a remarkable percentage of chromosomally abnormal embryos can develop normally to blastocyst stage with high probability of implantation and pregnancy.

Insulin and oxidative stress modulate proliferation of rat ovarian theca-interstitial cells through diverse signal transduction pathways.

Insulin and moderate oxidative stress stimulate proliferation of ovarian theca-interstitial cells. The effects of these agents on selected signal transduction pathways were examined. PD98059 (inhibitor of MAP2K1, also known as MEK-1, upstream of extracellular signal-regulated protein kinases MAPK3/1, also known as ERK1/2), wortmannin (inhibitor of PIK3C2A, also known as PI3K), and rapamycin (inhibitor of FRAP1, also known as mTOR, upstream of RPS6KB1) each significantly decreased insulin and oxidative stress-induced proliferation of theca-interstitial cells. The greatest inhibition was observed in the presence of rapamycin; this effect occurred without a significant change in cell viability. Phosphorylation of AKT was stimulated by insulin only, while phosphorylation of MAPK3/1 and RPS6KB1 was increased by insulin and oxidative stress. Insulin-induced and oxidative stress-induced phosphorylation of RPS6KB1 was partly inhibited by wortmannin and partly by PD98059; the greatest inhibition was observed in the presence of a combination of wortmannin plus PD98059. Effects of insulin and oxidative stress on phosphorylation of RPS6KB1 were confirmed by kinase activity assays. These findings indicate that actions of insulin and oxidative stress converge on MAPK3/1 and RPS6KB1. Furthermore, we speculate that activation of RPS6KB1 may be in part induced via the MAPK3/1 pathway.

Embryo aneuploidy screening for unexplained recurrent miscarriage: a minireview.

PROBLEM: The aim of this study was to investigate the incidence of chromosomal abnormalities in unexplained recurrent miscarriage (RM) patients and assess the role of pre-implantation genetic diagnosis (PGD) in preventing subsequent pregnancy loss and improving pregnancy outcome. METHOD OF STUDY: Pre-implantation genetic diagnosis was performed in 241 RM cycles and in 35 cycles in patients undergoing PGD for sex-linked diseases (control group). Chromosomes 13, 16, 18, 21, 22, X and Y were analysed by fluorescence in situ hybridization. RESULTS: The implantation and pregnancy rates in RM patients were 26.4 and 36.5% versus 20.6 and 29.0% in the control group, respectively. The percentage of abnormal embryos was significantly increased in RM patients compared with controls. CONCLUSIONS: Recurrent miscarriage is associated with a higher incidence of chromosomally abnormal embryos. In vitro fertilization (IVF) plus PGD is an important step in the management of these couples.

Embryonic chromosomal abnormalities obtained after rescue intracytoplasmic sperm injection of 1-day-old unfertilized oocytes.

PURPOSE: To study if second day intracytoplasmic sperm injection (ICSI) results in chromosomal abnormalities in the embryos. METHODS: Rescue ICSI was performed on 14 metaphase II (MII) oocytes after unsuccessful conventional IVF, four were fertilized. Fluorescent in situ hybridization (FISH) was performed on these four embryos and was informative for three. RESULTS: There were two tetraploid embryos, one mosaic embryo with trisomy 21, tetrasomy 18, and tetrasomy for sex chromosomes in one cell and trisomy 22 in another cell. CONCLUSIONS: We discourage the use of second day ICSI due to the observed increase in chromosomal abnormalities in these embryos.

Preimplantation genetic diagnosis by fluorescence in situ hybridization: clinical possibilities and pitfalls.

Preimplantation genetic diagnosis using the fluorescence in situ hybridization technique (FISH) is being used widely to prevent the transmission of sex-linked diseases, to screen for translocations, and for aneuploidy screening in specific in vitro fertilization (IVF) patient groups, along with FISH analysis of spermatozoa in infertile men. In this study, we aim to critically analyze our clinical results in patients at risk of transmitting sex-linked diseases (n = 55), in carriers of translocations (n = 43), in women who have recurrent miscarriage (two or more miscarriages) (n = 128), recurrent IVF failure (three or more failed IVF attempts) (n = 47), and patients of advanced maternal age (37 years old or older) (n = 79). The use of the FISH technique in carriers of sex-linked diseases and translocation patients prevents transmission of these conditions and provides good IVF outcome. In patients with recurrent miscarriage, implantation failure, and advanced maternal age, a high incidence of embryos with abnormal chromosomes 13,16,18,21,22, X, and Y was observed (range 69-75%), as expected. In those three groups of patients, the selection of euploid embryos for transfer resulted in good pregnancy rates with a low incidence of miscarriage. Limitations and pitfalls of this technique are also discussed.

Estradiol down-regulates MCP-1 expression in human coronary artery endothelial cells.

OBJECTIVE: To determine whether estrogen down-regulates MCP-1 in vascular endothelial cells. DESIGN: A prospective comparative study. SETTING: Academic research environment. PATIENT(S): Human umbilical vein endothelial cells (n = 3) and human coronary artery endothelial cells (n = 3) obtained from females. INTERVENTION(S): Human umbilical vein endothelial cells (HUVEC) and human coronary artery endothelial cells (HCAEC) were grown to preconfluence. Then, they were treated with various concentrations of estradiol (10(-11) M to 10(-7) M) as well as raloxifene (10(-7) M) and tamoxifen (10(-7) M). MCP-1 in culture media was quantified using an enzyme-linked immunosorbent assay (ELISA). Cellular ribonucleic acid (RNA) was extracted and Northern blots were hybridized with an oligonucleotide probe complementary to a specific sequence of MCP-1 mRNA. MAIN OUTCOME MEASURE(S): MCP-1 protein and mRNA. RESULT(S): Estrogen treatment did not change MCP-1 expression in HUVEC. On the other hand, in HCAEC, estradiol induced a 30% decrease in mRNA expression and resulted in dose-dependent inhibition of MCP-1 production as detected by ELISA. Raloxifene and tamoxifen also resulted in inhibition of MCP-1 mRNA and protein expression. CONCLUSION(S): Our findings suggest that one of the mechanisms by which estrogen down-regulates atherosclerosis is by suppressing vascular MCP-1 expression, resulting in decreased macrophage recruitment.