F&S science最新文献

Objective

To validate the detection of abnormal ploidy in preimplantation embryos and evaluate its frequency in transferrable blastocysts.

Design

A high-throughput genome-wide single nucleotide polymorphism microarray-based preimplantation genetic testing (PGT) platform was validated using multiple positive controls, including cell lines of known haploid and triploid karyotypes and rebiopsies of embryos with initial abnormal ploidy results. This platform was then tested on all trophectoderm biopsies in a single PGT laboratory to calculate the frequency of abnormal ploidy and the parental and cell division origins of error.

Setting

Preimplantation genetic testing laboratory.

Patient(s)

The embryos from in vitro fertilization patients who elected for PGT were evaluated. Any patients who provided saliva samples were further analyzed for the parental and cell division origins of abnormal ploidy.

Intervention(s)

None.

Main Outcome Measure(s)

Evaluable positive controls showed 100% concordance with original karyotypes. The overall frequency of abnormal ploidy within a single PGT laboratory cohort was 1.43%.

Result(s)

All cell lines showed 100% concordance with the expected karyotype. Additionally, all evaluable rebiopsies showed 100% concordance with the original abnormal ploidy karyotype. The frequency of abnormal ploidy was 1.43%, with 29% of those being haploid or uniparental isodiploid, 2.5% uniparental heterodiploid, 68% triploid, and 0.4% tetraploid. Twelve haploid embryos contained maternal deoxyribonucleic acid, and 3 contained paternal deoxyribonucleic acid. Thirty-four triploid embryos were of maternal origin, and 2 were of paternal origin. Thirty-five triploid embryos had a meiotic origin of error, and 1 was of mitotic error. Of those 35 embryos, 5 originated from meiosis I, 22 originated from meiosis II, and 8 were deemed inconclusive. On the basis of specific abnormal ploidy karyotypes, 41.2% of embryos would be falsely classified as euploid, and 22.7% would be false-positive mosaics with the use of the conventional next-generation sequencing–based PGT methods.

Conclusion(s)

This study demonstrates the validity of a high-throughput genome-wide single nucleotide polymorphism microarray-based PGT platform to accurately detect abnormal ploidy karyotypes and predict the parental and cell division origins of error of evaluable embryos. This unique method improves the sensitivity of detection for abnormal karyotypes, which can reduce the chances of adverse pregnancy outcomes.

Objective

To examine the association between keloids, hypertrophic scars, and uterine fibroid incidence as well as growth. Both keloids and fibroids are fibroproliferative conditions that have been reported to be more prevalent among Blacks than Whites, and they share similar fibrotic tissue structures, including extracellular matrix composition, gene expression, and protein profiles. We hypothesized that women with a history of keloids would have greater uterine fibroid development.

Design

A prospective community cohort study (enrollment 2010–2012) with 4 study visits over 5 years to conduct standardized ultrasounds to detect and measure fibroids ≥0.5 cm in diameter, assess the history of keloid and hypertrophic scars, and update covariates.

Setting

Detroit, Michigan area.

Patients

A total of 1,610 self-identified Black and/or African American women aged 23–35 years at enrollment without a previous clinical diagnosis of fibroids.

Exposure(s)

Keloids (raised scars that grow beyond the margins of the original injury) and hypertrophic scars (raised scars that stay within the bounds of the original injury). Because of the difficulties in distinguishing keloids and hypertrophic scars, we separately examined the history of keloids and the history of either keloids or hypertrophic scars (any abnormal scarring) and their associations with fibroid incidence and growth.

Main Outcome Measure(s)

Fibroid incidence (new fibroid after a fibroid-free ultrasound at enrollment) was assessed using Cox proportional-hazards regression. Fibroid growth was assessed using linear mixed models. The estimates for the change in log volume per 18 months were converted to the estimated percentage difference in volume for scarring vs. no-scarring. Both incidence and growth models were adjusted for time-varying demographic, reproductive, and anthropometric factors.

Result(s)

Of the 1,230 fibroid-free participants, 199 (16%) reported ever having keloids, 578 (47%) reported keloids or hypertrophic scars, and 293 (24%) developed incident fibroids. Neither keloids (adjusted hazard ratio = 1.04; 95% confidence interval: 0.77, 1.40) nor any abnormal scarring (adjusted hazard ratio = 1.10; 95% confidence interval: 0.88, 1.38) were associated with fibroid incidence. Fibroid growth differed little by scarring status.

Conclusion(s)

Despite molecular similarities, self-reported keloid and hypertrophic scars did not show an association with fibroid development. Future research may benefit from the examination of dermatologist-confirmed keloids or hypertrophic scars; however, our data suggest little shared susceptibility for these 2 types of fibrotic conditions.

Segmental aneuploidies (SAs) are structural imbalances, namely, gains or losses, involving a chromosomal segment. Most preimplantation genetic testing platforms can detect segmental imbalances greater than 5–10 Mb, either full or mosaic; however, questions remain about clinical significance. An in-depth review was performed to determine the accuracy, frequency, and types of SAs detected in preimplantation embryos. A comprehensive search of the literature revealed an incidence of approximately 8.15% in preimplantation embryos, compared with a prevalence of 3.55% in prenatal diagnosis samples. Several studies have used rebiopsy analysis to validate the accuracy and reproducibility of such findings in blastocyst-stage embryos. A comparison of these studies yielded a mean confirmation rate of SAs slightly higher than 30%. This result could be attributed to their mitotic origin as well as to the technical limitations of preimplantation genetic testing. In addition, the few available studies in which embryos with a segmental finding were transferred in utero are analyzed to discuss the reproductive competence of such embryos. Except for 1 study, all outcomes were described for segmental embryos in a mosaic state. As a result, there is still insufficient evidence to provide accurate information about the effect of segmental imbalances on embryonic reproductive competence and to determine gestational and newborn risks.

Although much of the foundational basic scientific and clinical research was conducted in the United States, the first in vitro fertilization (IVF) birth occurred in the United Kingdom. Why? For centuries, all research surrounding the field of “reproduction” has elicited bipolar passionate responses by the American public, and the issue of “test tube babies” has been no different. The history of conception in the United States is defined by complex interrelationships among scientists, clinicians, and politically charged decisions by various branches of the US government. With a focus on research in the United States, this review summarizes the early scientific and clinical advances important to the development of IVF and then addresses the potential future developments in IVF. We also consider what future advances are possible in the United States given the current regulations, laws, and funding.

Objective

To investigate the quantity of 2 stem cell types in the endometrial stroma of women undergoing in vitro fertilization and their association with steroid hormone signaling and implantation success after embryo transfer.

Design

Prospective cohort study.

Setting

Private hospital.

Patient(s)

A total of 109 patients undergoing in vitro fertilization.

Intervention(s)

Not applicable.

Main Outcome Measure(s)

Immunohistochemistry staining of endometrial biopsies taken during the midluteal phase using antibodies against NOTCH1 and CD117 was performed. The percentage of endometrial stromal cells positive for these markers was determined. The link of these stem cell percentages with the serum progesterone and estradiol levels and the endometrial expression of their respective receptors were assessed. After embryo transfer, the quantity of stained cells for each marker was also compared according to implantation outcome.

Result(s)

The percentage of NOTCH1+ stromal cells ranged from 0.003%–2.112% (median, 0.062%) and was significantly higher than that of CD117+ cells, which ranged from 0.000%–0.210% (median, 0.020%) (Z = −7.035). The percentage of NOTCH1+ stem cells showed no difference between the studied serum hormone level groups and no relationship with the expression of their receptors in the endometrium. In contrast, the number of CD117+ cells significantly differed between patients with high and low levels of serum progesterone (cutoff, 14.9 ng/mL) and estradiol (cutoff, 135.6 pg/mL). Furthermore, the quantity of CD117+ stem cells was positively correlated with the progesterone receptor (R = 0.277) and estradiol receptor (R= 0.318) expression levels in the endometrium. Although the quantity of NOTCH1+ cells did not differ between the 2 implantation groups, the median percentage of CD117+ cells was significantly higher in patients with successful implantation than in those with unsuccessful implantation (0.03% vs. 0.01%, respectively). The cutoff value for the percentage of CD117+ cells predicting successful implantation was 0.018% (area under the curve, 0.66; 95% confidence interval, 0.56–0.77; sensitivity, 63.1%; specificity, 61.4%).

Conclusion(s)

This study indicates that the quantity of certain stem cell types (CD117+), but not others (NOTCH1+), in the functional endometrium is associated with implantation success and sex hormone signaling during the midluteal phase. These findings highlight the role of CD117+ cells in preparing the endometrium for embryo implantation, and their quantity may be an indirect indicator of endometrial receptivity.

Preimplantation genetic testing for aneuploidy (PGT-A) was developed to identify euploid embryos from a cohort of embryos with unknown ploidy produced during an in vitro fertilization (IVF) cycle. In recent years, the ability of PGT-A to improve IVF outcomes has come into question. The goal of this review was to summarize the major randomized controlled trials (RCTs) and nonselection studies evaluating the benefit of PGT-A to improve the live birth rates (LBRs). We argue that the LBR per transfer is more relevant to the individual patient than the cumulative LBR as a means to minimize the burden of IVF by reducing futile transfers, pregnancy losses, and ongoing aneuploidy. The early RCTs demonstrate improved implantation rates and LBRs with PGT-A for embryo selection vs. traditional morphology. However, these studies are limited by the small sample size and a bias toward good-prognosis patients. Further studies using next-generation sequencing found more variable results but did confirm an improvement in the LBRs per transfer in an older population with a higher baseline risk of aneuploidy. The largest RCT to date showed similar cumulative LBRs in the PGT-A and control groups after biopsy and sequential transfer of up to 3 blastocysts with a significant reduction in the cumulative clinical pregnancy loss rate in the PGT-A group. Nonselection studies evaluating pregnancy outcomes after transfer of euploid vs. aneuploid embryos demonstrate near-perfect negative predictive value for an aneuploid result to predict live birth. Putative mosaic embryos had similar LBRs compared with euploid embryos. The available RCTs and nonselection studies support the practice of using PGT-A to identify euploid embryos for transfer, especially in an older population, while simultaneously selecting against aneuploid embryos, without negative impact on the total reproductive potential of the cycle.

Objective

To study the implications of decreased zinc and tetrahydrobiopterin (H₄B) associated with chronological aging on oocyte quality using a mouse model. H₄B and zinc are essential cofactors for nitric oxide synthase (NOS), because they aid in electron transfer and dimeric stability, and their bioavailability is crucial in regulating NOS coupling. We have previously shown that sufficient levels of nitric oxide (NO) are essential for maintaining oocyte quality and activation, and NO levels decrease in the oocyte as a function of age. Thus, it is plausible that zinc and H₄B may decrease as a function of age, resulting in NOS dysfunction with subsequent depletion of NO. Additionally, increased production of reactive oxygen species from the monomeric form can further disrupt oocyte quality and NO bioavailability.

Design

Experimental laboratory study.

Setting

Laboratory.

Animals

B6D2F1 mice.

Intervention(s)

Sibling oocytes were retrieved from super-ovulated B6D2F1 mice from 3 age groups: 8–14 weeks (young breeders [YBs]), 48–52 weeks (retired breeders [RBs]), and 80–84 weeks (old animals [OAs]).

Main Outcome Measure(s)

Oocytes were scored for ooplasmic/spindle microtubule (MT) morphology, chromosomal alignment, and cortical granule (CG) intactness using immunofluorescence and confocal microscopy with 3 dimension image reconstruction and subjected to an high-performance liquid chromatography assay to measure the concentrations of H₄B and its metabolites, as well as the zinc measurement using atomic absorption spectrophotometry.

Result(s)

Oocyte scoring showed a reduction in “good” quality oocyte percentage as age increases, with YB having the highest percentage of quality oocytes followed by RB and OA. The high-performance liquid chromatography analysis showed a significant progressive decrease in total H₄B in RB and OA (0.00098 picogram (pg)/oocyte and 0.00069 pg/oocyte, respectively) compared with YB (0.00125 pg/oocyte). Atomic absorbance spectrophotometry revealed a significant progressive decrease in zinc concentration in RB and OA compared with YB (8.45 pg/oocyte and 5.82 pg/oocyte vs. 10.05 pg/oocyte, respectively).

Conclusion(s)

Age-related diminution in oocyte quality is paralleled by a decline in the levels of H₄B and zinc. The resultant deficiency in the oocytes can lead to the inability of NOS to maintain dimerization. Consequent uncoupling of NOS generates superoxide instead of NO, which participates in a multitude of reactions contributing to oxidative stress. Therefore, dysfunction of NOS secondary to zinc and H₄B loss is a major mechanism inv