Associations between the artificial intelligence scoring system and live birth outcomes in preimplantation genetic testing for aneuploidy cycles

BACKGROUND

Several studies have demonstrated that iDAScore is more accurate in predicting pregnancy outcomes in cycles without preimplantation genetic testing for aneuploidy (PGT-A) compared to KIDScore and the Gardner criteria. However, the effectiveness of iDAScore in cycles with PGT-A has not been thoroughly investigated. Therefore, this study aims to assess the association between artificial intelligence (AI)-based iDAScore (version 1.0) and pregnancy outcomes in single-embryo transfer (SET) cycles with PGT-A.

METHODS

This retrospective study was approved by the Institutional Review Board of Chung Sun Medical University, Taichung, Taiwan. Patients undergoing SET cycles (n = 482) following PGT-A at a single reproductive center between January 2017 and June 2021. The blastocyst morphology and morphokinetics of all embryos were evaluated using a time-lapse system. The blastocysts were ranked based on the scores generated by iDAScore, which were defined as AI scores, or by KIDScore D5 (version 3.2) following the manufacturer's protocols. A single blastocyst without aneuploidy was transferred after examining the embryonic ploidy status using a next-generation sequencing-based PGT-A platform. Logistic regression analysis with generalized estimating equations was conducted to assess whether AI scores are associated with the probability of live birth (LB) while considering confounding factors.

RESULTS

Logistic regression analysis revealed that AI score was significantly associated with LB probability (adjusted odds ratio [OR] = 2.037, 95% confidence interval [CI]: 1.632-2.542) when pulsatility index (PI) level and types of chromosomal abnormalities were controlled. Blastocysts were divided into quartiles in accordance with their AI score (group 1: 3.0-7.8; group 2: 7.9-8.6; group 3: 8.7-8.9; and group 4: 9.0-9.5). Group 1 had a lower LB rate (34.6% vs. 59.8-72.3%) and a higher rate of pregnancy loss (26% vs. 4.7-8.9%) compared with the other groups (p < 0.05). The receiver operating characteristic curve analysis verified that the iDAScore had a significant but limited ability to predict LB (area under the curve [AUC] = 0.64); this ability was significantly weaker than that of the combination of iDAScore, type of chromosomal abnormalities, and PI level (AUC = 0.67). In the comparison of the LB groups with the non-LB groups, the AI scores were significantly lower in the non-LB groups, both for euploid (median: 8.6 vs. 8.8) and mosaic (median: 8.0 vs. 8.6) SETs.

CONCLUSIONS

Although its predictive ability can be further enhanced, the AI score was significantly associated with LB probability in SET cycles. Euploid or mosaic blastocysts with low AI scores (≤ 7.8) were associated with a lower LB rate, indicating the potential of this annotation-free AI system as a decision-support tool for deselecting embryos with poor pregnancy outcomes following PGT-A.

Significantly shortened telomere length and altered androgen receptor level in cumulus cells from women with polycystic ovary syndrome

OBJECTIVE

The aim of this study was to investigate the correlation between hormone receptor levels and telomere length (TL) in infertile women with and without polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

This prospective cohort study recruited a total of 431 cumulus oocyte complex (COC) from 88 infertile women between July 2012 and June 2014. The participants were divided into three groups: young age (<38 years, n = 42 and 227 COC), advanced age (≥38 years, n = 33 and 107 COC) and PCOS patients (n = 13 and 97 COC). Cumulus cells were collected from individual follicle during oocyte pick-up, and the mRNA levels of hormone receptors and TL were measured using real-time PCR.

RESULTS

The cumulus cells of PCOS patients demonstrated lower mRNA levels of LH receptor (75.57 ± 138.10 vs. 171.07 ± 317.68; p < 0.01) and androgen receptor (1.13 ± 1.52 vs. 4.08 ± 9.57; p < 0.01), as well as a shorter TL (2.39 ± 2.58 vs. 3.96 ± 4.72; p < 0.01) compared to those of the young age group. In the young age group, only androgen receptor mRNA level showed a significant association with TL (rho = 0.148, p = 0.026), while FSH receptor mRNA level was the only factor associated with TL (rho = 0.247, p = 0.015) in PCOS patients. For advanced-aged patients, no significant relationship was observed between hormone receptor mRNA levels and TL. Alternative splicing of androgen receptors was identified in some PCOS patients but not in young age controls.

CONCLUSION

The findings suggest that the androgen receptor level and function may be altered in the cumulus cells of PCOS patients, leading to a shorter TL in cumulus cells in PCOS patients.

Chromosomal, gestational, and neonatal outcomes of embryos classified as a mosaic by preimplantation genetic testing for aneuploidy

OBJECTIVE

To understand the clinical risks associated with the transfer of embryos classified as a mosaic using preimplantation genetic testing for aneuploidy.

DESIGN

Analysis of data collected between 2017 and 2023.

SETTING

Multicenter.

PATIENTS

Patients of infertility treatment.

INTERVENTION

Comparison of pregnancies resulting from embryos classified as euploid or mosaic using the 20%-80% interval in chromosomal intermediate copy numbers to define a mosaic result.

MAIN OUTCOME MEASURES

Rates of spontaneous abortion, birth weight, length of gestation, incidence of birth defects, and chromosomal status during gestation.

RESULTS

Implanted euploid embryos had a significantly lower risk of spontaneous abortion compared with mosaic embryos (8.9% [n = 8,672; 95% confidence interval {CI95} 8.3, 9.5] vs. 22.2% [n = 914; CI95 19.6, 25.0]). Embryos with mosaicism affecting whole chromosomes (not segmental) had the highest risk of spontaneous abortion (27.6% [n = 395; CI95 23.2, 32.3]). Infants born from euploid, mosaic, and whole chromosome mosaic embryos had average birth weights and lengths of gestation that were not statistically different (3,118 g and 267 days [n = 488; CI95 3,067, 3,169, and 266, 268], 3052 g and 265 days [n = 488; CI95 2,993, 3,112, and 264,267], 3,159 g and 268 days [n = 194; CI95 3,070, 3,249, and 266,270], respectively). Out of 488 infants from mosaic embryo transfers (ETs), one had overt gross abnormalities as defined by the Centers for Disease Control and Prevention. Most prenatal tests performed on pregnancies from mosaic ETs had normal results, and only three pregnancies produced prenatal test results reflecting the mosaicism detected at the embryonic stage (3 out of 250, 1.2%; CI95 0.25, 3.5).

CONCLUSION

Although embryos classified as mosaic experience higher rates of miscarriage than euploid embryos (with a particularly high frequency shortly after implantation), infants born of mosaic ETs are similar to infants of euploid ETs. Prenatal testing indicates that mosaicism resolves during most pregnancies, although this process is not perfectly efficient. In a small percentage of cases, the mosaicism persists through gestation. These findings can serve as risk-benefit considerations for mosaic ETs in the fertility clinic.

Factors Affecting the Potential Efficacy of Intrauterine Platelet-Rich Plasma Infusion on Thin Endometrium in Women with Recurrent Implantation Failure

Optimizing endometrial thickness (EMT) is crucial for successful embryo implantation, but enhancing thin endometrium remains a significant challenge. Platelet-rich plasma (PRP)-derived therapies have emerged as a promising approach in reproductive medicine due to their capacity to facilitate tissue repair and regeneration. This study aims to identify the risk factors associated with the failure of intrauterine PRP infusion for thin endometrium in women with recurrent implantation failure (RIF). We retrospectively reviewed data from 77 women with RIF, all exhibiting an EMT of <7 mm. These women underwent programmed hormone therapy for frozen embryo transfer (FET) and received two autologous intrauterine PRP infusions. Following intrauterine PRP-lysate (PL) infusions, the mean increase in EMT was 1.9 ± 1.2 mm, with EMT reaching 7 mm in 86% of the cases (66/77; average EMT, 8.3 mm). We identified an exceedingly thin EMT as a risk factor impacting the therapeutic efficacy in increasing EMT (p = 0.04, OR: 3.16; 95% CI: 1.03-9.67). Additionally, the number of previous uterine surgeries emerged as a prognostic factor for pregnancy failure following PL infusion (p = 0.02, OR: 2.02; 95% CI: 1.12-3.64). Our findings suggest that an extremely thin EMT and a history of numerous uterine surgeries can impede successful pregnancy, even when an optimal EMT is achieved following PRP infusion.

Increased incidence of live births in implanted day 5 versus day 6 blastocysts following single embryo transfers with PGT-A

Elective single-embryo transfers of euploid or low-level mosaic blastocysts were analyzed in this retrospective study to determine the correlations of live birth (LB) probability with embryonic developmental features of implanted day 5 (D5, n = 245) or day 6 (D6, n = 73) blastocysts using time-lapse (TL) monitoring. According to the logistic regression analyses (adjusted odds ratio [OR] = 0.341, 95% confidence interval [CI] = 0.169-0.685, P < 0.05), the LB probability was negatively associated with the D6 group. The LB rate of the D5 group was higher than the D6 group (88.2% vs. 75.3%; P < 0.05). Compared with the D5 blastocysts, the D6 blastocysts exhibited comparable dysmorphisms except for the multinucleation at the 4-cell stage (10.9% vs. 2.9%, P < 0.05). Moreover, D6 blastocysts had considerably slower developmental kinetics and poorer blastocyst morphologies. Further analysis confirmed that the LB rate was not associated with developmental kinetics or dysmorphisms but rather with blastocyst morphology (inner cell mass [ICM] grade ≤ C vs. ICM grade A, adjusted OR = 0.155, 95% CI = 0.04-0.596, P < 0.05; trophectoderm [TE] grade ≤ C vs. TE grade A, adjusted OR = 0.157, 95% CI = 0.032-0.760, P < 0.05). In conclusion, D6 implanted blastocysts have a considerably lower LB rate than D5 implanted blastocysts. As determined by TL monitoring, the diminished blastocyst morphology can be one of the primary reasons underlying the decreased likelihood of LB.

Comparison of clinical outcome between day 5 and day 6 single blastocyst transfers in cycles undergoing preimplantation genetic testing for aneuploidy

OBJECTIVE

In vitro fertilization (IVF) treatment has gradually adopted the practice of culturing embryos until the blastocyst stage on the D5 or D6 as the standard approach. PGT-A is commonly used in vitro fertilization (IVF). This study aimed to evaluate the clinical outcomes of frozen embryo transfers (FETs) using single blastocyst transfers (SBTs) on the fifth (D5) or sixth (D6) day of development in cycles that underwent preimplantation genetic testing for aneuploidy (PGT-A).

MATERIALS AND METHODS

The patients who had at least one euploid or mosaic blastocyst of good quality determined by PGT-A results and received single embryo transfer (SET) cycles were included in the study. In this study, the live birth rate (LBR) and neonatal outcomes were compared after the transfer of single biopsied D5 and D6 blastocysts in frozen embryo transfer (FET) cycles.

RESULTS

A total of 527 frozen-thawed blastocyst transfer (FET) cycles (8449 biopsied embryos were analyzed). No significant difference in the implantation rate (IR), clinical pregnancy rate (CPR), and live birth rate (LBR) between the transfers of D5 and D6 blastocysts. Birth weight was the only perinatal outcome that showed a significant difference between the D5 and D6 groups.

CONCLUSION

The study confirmed that the transfer of a single euploid or mosaic blastocyst, regardless of whether it was on the fifth (D5) or sixth (D6) day of development, can lead to promising clinical results.

Presence of vacuoles in blastocysts is negatively associated with euploidy and live birth rates

OBJECTIVE

To investigate whether the presence of vacuoles in biopsied blastocysts is associated with the likelihood of aneuploidy and clinical outcomes.

DESIGN

Retrospective observational study.

SUBJECTS

This study retrospectively analyzed data obtained through preimplantation genetic testing for aneuploidy (PGT-A) performed on 3351 blastocysts from 826 patients at a single reproductive center between August 2018 and July 2020. Ultimately, 167 single euploid blastocyst transfers were performed in these patients. Vacuoles existing in the trophectoderm or inner cell mass were observed using blastocyst biopsy. After biopsy, all blastocysts were vitrified, and embryo transfer was performed in a subsequent treatment cycle.

EXPOSURE

Presence versus absence of vacuoles.

MAIN OUTCOME MEASURES

The associations between vacuoles and euploidy or live birth rates were assessed using logistic regression models and estimated adjusted odds ratios [ORs] and 95% confidence intervals (CIs).

RESULTS

Of the 3351 blastocysts from 826 patients, 903 (26.9%) were discovered to have vacuoles. The vacuole-positive group had a significantly lower percentage of euploid blastocysts after TE biopsy than did the vacuole-negative group (28.8% vs. 35.5%; p < 0.001). Embryos with vacuoles were significantly more likely to be poor quality (30.6% vs. 18.2%, p < 0.001). Logistic regression analyses revealed that euploid blastocysts were positively associated with the absence of vacuoles, maternal age, and good embryo quality (vacuole-negative group: adjusted OR= 1.291, 95% CI = 1.089-1.530; age < 38 years: adjusted OR= 1.989, 95% CI = 1.692-2.337; good embryo quality: adjusted OR = 1.703, 95% CI = 1.405-2.064). The implantation rate and live birth rate were significantly lower for the transferred single euploid blastocysts with vacuoles than for the blastocysts without vacuoles (35.5% vs. 56.6%, p = 0.033; 29.0% vs. 52.2%, p = 0.020, respectively). The live birth rate was positively associated with the absence of vacuoles (adjusted OR = 2.792, 95% CI = 1.180-6.608).

CONCLUSION

The formation of vacuoles in blastocysts is associated with lower rates of euploidy and live birth. Blastocysts without vacuoles should thus be prioritized for embryo transfer in in vitro fertilization cycles.

Biphasic oxygen tension promotes the formation of transferable blastocysts in patients without euploid embryos in previous monophasic oxygen cycles

This study evaluated whether the concentration of biphasic O₂ (5-2%) promotes the formation of qualified blastocysts (QBs) and euploid blastocysts and the probability of cycles with transferable blastocysts. The paired experimental design included a total 90 patients (180 cycles) without euploid blastocysts in previous monophasic O₂ (5%) cycles were enrolled for an additional cycle of biphasic O₂ (5-2%). In the biphasic O₂ (5-2%) group, the QB rate (35.8%, 225/628) was significantly higher than that in the monophasic O₂ (5%) group (23.5%, 137/582; p < 0.001). In addition, the euploid blastocyst number (0.5 ± 0.8) and the percentage of cycles with transferable blastocysts were significantly higher in the biphasic O₂ (5-2%) group (57.8%, 52/90) than those in the monophasic O₂ (5%) group (0 and 35.6%, 32/90, respectively; p < 0.01). Multivariable regression analysis also indicated that the QB rate and the probability of cycles with transferable blastocysts correlated with O₂ tension (OR 1.535, 95% CI 1.325-1.777, and OR 3.191, 95% CI 1.638-5.679, respectively; p < 0.001). Biphasic O₂ culture can be used as an alternative strategy to increase the euploid QBs and the probability of cycles with transferable blastocysts in patients with a poor prognosis.

Association between Leukemia Inhibitory Factor Gene Polymorphism and Clinical Outcomes among Young Women with Poor Ovarian Response to Assisted Reproductive Technology

BACKGROUND

Does the presence of single-nucleotide polymorphisms (SNPs) in the leukemia inhibitory factor (LIF) gene affect ovarian response in infertile young women?

METHODS

This was a case-control study recruiting 1744 infertile women between January 2014 to December 2015. The 1084 eligible patients were stratified into four groups using the POSEIDON criteria. The gonadotropin-releasing hormone receptor (GnRHR), follicle-stimulating hormone receptor (FSHR), anti-Müllerian hormone (AMH), and LIF SNP genotypes were compared among the groups. The distributions of LIF and FSHR among younger and older patients were compared. Clinical outcomes were also compared.

RESULTS

The four groups of poor responders had different distributions of SNP in LIF. The prevalence of LIF genotypes among young poor ovarian responders differed from those of normal responders. Genetic model analyses in infertile young women revealed that the TG or GG genotype in the LIF resulted in fewer oocytes retrieved and fewer mature oocytes relative to the TT genotypes. In older women, the FSHR SNP genotype contributed to fewer numbers of mature oocytes.

CONCLUSIONS

LIF and FSHR SNP genotypes were associated with a statistically significant reduction in ovarian response to controlled ovarian hyperstimulation in younger and older women with an adequate ovarian reserve, respectively.

Assessment of Telomere Length and Mitochondrial DNA Copy Number in Granulosa Cells as Predictors of Aneuploidy Rate in Young Patients

Background: To identify the correlation among female age, cellular aging markers, and aneuploidy rate in in vitro fertilization (IVF) and the preimplantation genetic test for aneuploidy (PGT-A) cycles. Methods: This is a prospective cohort study recruiting 110 infertile women between August 2017 and July 2018. They were divided into young-age (<38 years, n = 60) and advanced-age (≥38 years, n = 50) groups. Peripheral leukocytes were assessed, and the granulosa cells were pooled during oocyte pickup. Mitochondrial DNA (mtDNA) copy number and telomere length (TL) were measured using real-time polymerase chain reaction. PGT-A was performed on the NGS platform. Results: mtDNA copy number and TL were positively correlated in both leukocytes (rho = 0.477, p < 0.001) and granulosa cells (rho = 0.361, p < 0.001), but the two parameters in leukocytes were not correlated with those in granulosa cells. In the young-age group, TL in the granulosa cells was the only factor correlated with the aneuploidy rate (rho = −0.283, p = 0.044), whereas in the advanced-age group, age was the main factor (rho = 0.358, p = 0.018). Conclusions: TL in the granulosa cells was negatively correlated with the aneuploidy rate in the young-age group, supporting the application of PGT-A in younger women.

Blastocyst Morphology Based on Uniform Time-Point Assessments is Correlated With Mosaic Levels in Embryos

Avoiding aneuploid embryo transfers has been shown to improve pregnancy outcomes in patients with implantation failure and pregnancy loss. This retrospective cohort study aims to analyze the correlation of time-lapse (TL)-based variables and numeric blastocyst morphological scores (TLBMSs) with different mosaic levels. In total, 918 biopsied blastocysts with time-lapse assessments at a uniform time-point were subjected to next-generation sequencing–based preimplantation genetic testing for aneuploidy. In consideration of patient- and cycle-related confounding factors, all redefined blastocyst morphology components of low-grade blastocysts, that is, expansion levels (odds ratio [OR] = 0.388, 95% confidence interval [CI] = 0.217–0.695; OR = 0.328, 95% CI = 0.181–0.596; OR = 0.343, 95% CI = 0.179–0.657), inner cell mass grades (OR = 0.563, 95% CI = 0.333–0.962; OR = 0.35, 95% CI = 0.211–0.58; OR = 0.497, 95% CI = 0.274–0.9), and trophectoderm grades (OR = 0.29, 95% CI = 0.178–0.473; OR = 0.242, 95% CI = 0.143–0.411; OR = 0.3, 95% CI = 0.162–0.554), were less correlated with mosaic levels ≤20%, <50%, and ≤80% as compared with those of top-grade blastocysts (p < 0.05). After converting blastocyst morphology grades into scores, high TLBMSs were associated with greater probabilities of mosaic levels ≤20% (OR = 1.326, 95% CI = 1.187–1.481), <50% (OR = 1.425, 95% CI = 1.262–1.608), and ≤80% (OR = 1.351, 95% CI = 1.186–1.539) (p < 0.001). The prediction abilities of TLBMSs were similar for mosaic levels ≤20% (AUC = 0.604, 95% CI = 0.565–0.642), <50% (AUC = 0.634, 95% CI = 0.598–0.671), and ≤80% (AUC = 0.617, 95% CI = 0.576–0.658). In conclusion, detailed evaluation with TL monitoring at the specific time window reveals that redefined blastocyst morphology components and converted numeric TLBMSs are significantly correlated with all of the threshold levels of mosaicism. However, the performance of TLBMSs to differentiate blastocysts with aberrant ploidy risk remains perfectible.

O-201 Prenatal and postnatal outcome of mosaic embryo transfers: multicentric study of one thousand mosaic embryos diagnosed by preimplantation genetic testing with trophectoderm biopsy

Study question

To explore the effect of chromosomal mosaicism detected in preimplantation genetic testing (PGT-A) on prenatal and postnatal outcome of mosaic embryo pregnancies

Summary answer

No significant difference between euploid and mosaic embryos was observed in terms of weeks of gestation, average weight, and developmental defect of the babies born

What is known already

Mosaic embryos have the potential to implant and develop into healthy babies. Transfer of these embryos is now offered as an option for women who undergo IVF resulting in no euploid embryos. While, prenatal diagnosis has shown the depletion of chromosomal mosaicism in mosaic embryos, several concerns remain. For instance, the direct effects of different kind of mosaicism on prenatal/postnatal outcome and the possibility that intra-biopsy mosaicism in the TE is a poor predictor of the ploidy status of the ICM. Thus, there is certainly a need for comprehensive analyses of obstetrical and neonatal outcome data of transferred mosaic embryos.

Study design, size, duration

Compiled analysis from multicenter data on transfers of mosaic embryos (n = 1,000) and their outcome, with comparison to a euploid control group (n = 5,561). To explore the effect of embryonic mosaicism on newborns, we matched mosaic embryos resulting in a birth with a euploid embryo by a series of parameters (maternal age, embryo morphology, and indication for PGT-A). Prenatal tests and birth characteristics of &gt; 200 neonates from mosaic embryo transfers were compared to &gt; 200 euploid embryos.

Participants/materials, setting, methods

PGT-A was performed on blastocyst-stage embryos with 24-Chromosome whole genome amplification (WGA)-based Next Generation Sequencing (NGS). In accordance with established guidelines, embryos were categorized as mosaic when PGT-A results indicated 20-80% aneuploid content. Prenatal testing where performed in 30% of pregnancies with amniocentesis, 4% did an extra analysis for potential UPD for the suspected mosaic chromosome, and an additional 16% performed chorionic villus sampling (CVS) and 9.5% performed noninvasive prenatal testing (NIPT).

Main results and the role of chance

Of the 465 mosaic embryos that implanted, about 20% miscarried, and out of those, 75% were early spontaneous abortions. Of the pregnancies, 3 out of 368 were stillborn (2 out of them were twins that were extremely premature at 23 weeks, and the other died during pregnancy from a heart defect). The remaining 99% of those have been born or are late ongoing pregnancies at the time of analysis. Prenatal tests were performed in &gt; 200 pregnancies and the vast majority tested normal. All 5 abnormal cases were amniocentesis tests showing microdeletions or insertions of sizes smaller than the resolution used during PGT-A, so they were unrelated to the mosaicism detected with PGT-A. In fact, in none of the cases did the prenatal test reflect the mosaicism detected at the embryonic stage. Matching each of the 162 mosaic embryos resulting in a birth with a euploid embryo, we found that the length of gestation was similar on average, and so was the average weight of the babies at birth. We also gathered information on the routine physical examination performed on babies at birth, and of those 162 babies from mosaic embryo transfers, none had obvious developmental defects or gross abnormalities.

Limitations, reasons for caution

Even though newborns resulting from mosaic embryo transfers in this study invariably appeared healthy by routine examination, concerns for long-term health cannot yet be entirely dispelled. The question must therefore be carefully considered by each clinic and patient situation.

Wider implications of the findings

Prenatal testing of &gt; 200 pregnancies from mosaic embryo transfers showed no incidence of mosaicism that matched the PGT-A findings, indicating the involvement of self-corrective mechanisms. Pregnancy and obstetric data indicates that mosaic embryos prevailing through gestation and birth have similar chromosomal and physiological health compared to euploid embryos.

Trial registration number

none

Using outcome data from one thousand mosaic embryo transfers to formulate an embryo ranking system for clinical use

OBJECTIVE

To study how the attributes of mosaicism identified during preimplantation genetic testing for aneuploidy relate to clinical outcomes, in order to formulate a ranking system of mosaic embryos for intrauterine transfer.

DESIGN

Compiled analysis.

SETTING

Multi-center.

PATIENT(S)

A total of 5,561 euploid blastocysts and 1,000 mosaic blastocysts used in clinical transfers in patients undergoing fertility treatment.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Implantation (gestational sac), ongoing pregnancy, birth, and spontaneous abortion (miscarriage before 20 weeks of gestation).

RESULT(S)

The euploid group had significantly more favorable rates of implantation and ongoing pregnancy/birth (OP/B) compared with the combined mosaic group or the mosaic group affecting only whole chromosomes (implantation: 57.2% vs. 46.5% vs. 41.8%; OP/B: 52.3% vs. 37.0% vs. 31.3%), as well as lower likelihood of spontaneous abortion (8.6% vs. 20.4% vs. 25%). Whole-chromosome mosaic embryos with level (percent aneuploid cells) <50% had significantly more favorable outcomes than the ≥50% group (implantation: 44.5% vs. 30.4%; OP/B: 36.1% vs. 19.3%). Mosaic type (nature of the aneuploidy implicated in mosaicism) affected outcomes, with a significant correlation between number of affected chromosomes and unfavorable outcomes. This ranged from mosaicism involving segmental abnormalities to complex aneuploidies affecting three or more chromosomes (implantation: 51.6% vs. 30.4%; OP/B: 43.1% vs. 20.8%). Combining mosaic level, type, and embryo morphology revealed the order of subcategories regarding likelihood of positive outcome.

CONCLUSION(S)

This compiled analysis revealed traits of mosaicism identified with preimplantation genetic testing for aneuploidy that affected outcomes in a statistically significant manner, enabling the formulation of an evidence-based prioritization scheme for mosaic embryos in the clinic.

T cell-derived interferon-γ programs stem cell death in immune-mediated intestinal damage

Despite the importance of intestinal stem cells (ISCs) for epithelial maintenance, there is limited understanding of how immune-mediated damage affects ISCs and their niche. We found that stem cell compartment injury is a shared feature of both alloreactive and autoreactive intestinal immunopathology, reducing ISCs and impairing their recovery in T cell-mediated injury models. Although imaging revealed few T cells near the stem cell compartment in healthy mice, donor T cells infiltrating the intestinal mucosa after allogeneic bone marrow transplantation (BMT) primarily localized to the crypt region lamina propria. Further modeling with ex vivo epithelial cultures indicated ISC depletion and impaired human as well as murine organoid survival upon coculture with activated T cells, and screening of effector pathways identified interferon-γ (IFNγ) as a principal mediator of ISC compartment damage. IFNγ induced JAK1- and STAT1-dependent toxicity, initiating a proapoptotic gene expression program and stem cell death. BMT with IFNγ-deficient donor T cells, with recipients lacking the IFNγ receptor (IFNγR) specifically in the intestinal epithelium, and with pharmacologic inhibition of JAK signaling all resulted in protection of the stem cell compartment. In addition, epithelial cultures with Paneth cell-deficient organoids, IFNγR-deficient Paneth cells, IFNγR-deficient ISCs, and purified stem cell colonies all indicated direct targeting of the ISCs that was not dependent on injury to the Paneth cell niche. Dysregulated T cell activation and IFNγ production are thus potent mediators of ISC injury, and blockade of JAK/STAT signaling within target tissue stem cells can prevent this T cell-mediated pathology.

Clinical Outcomes of Single Mosaic Embryo Transfer: High-Level or Low-Level Mosaic Embryo, Does it Matter?

Recently, reports showed that embryos identified as mosaic after preimplantation genetic testing for aneuploid (PGT-A) could result in live birth with lower pregnancy and higher pregnancy loss rates compared with euploid embryos. However, the effects of mosaicism level on reproductive outcomes remain controversial. This study aimed to examine the level of mosaicism on pregnancy outcomes. Single mosaic embryo transfer was offered to 108 women who only had mosaic embryos. Mosaic embryos were labeled by utilizing next generation sequencing (NGS) based PGT-A for day 5/6 trophectoderm (TE)biopsies. TE biopsies containing < 50% abnormal cells were classified as low-level mosaicism and ≥ 50% as high-level mosaicism. To further confirm the concordance of chromosome constitution between TE and inner cell mass (ICM), 41 remaining embryos designated as mosaic blastocysts donated for research were also analyzed. Comparable live birth rate (LBR) but higher miscarriage rate (MR) was found in the high-level group. (LBR: low vs. high: 44.5% vs. 36%; p = 0.45, MR: low vs. high: 5.1% vs. 30.7%; p = 0.012). Analyses of TE and ICM from the remaining mosaic blastocysts show a poor concordance. This preliminary study demonstrated that high-level mosaic embryos could result in comparable LBR but higher MR.

Effect of Interval between Human Chorionic Gonadotropin Priming and Ovum Pick-up on the Euploid Probabilities of Blastocyst

This retrospective study attempts to elucidate the relevance of the interval between human chorionic gonadotropin priming and oocyte pick-up (hCG-OPU) to the euploidy probability of biopsied blastocysts in preimplantation genetic tests for aneuploidy (PGT-A) cycles. A total of 1889 blastocysts from 511 patients undergoing PGT- A cycles were used. An analysis of generalized estimating equations (GEE) was used to identify whether the hCG–OPU interval is associated with euploidy probabilities of blastocysts. Accordingly, maternal age (OR: 0.925, 95% CI: 0.903–0.948, p < 0.001) and the hCG–OPU interval (OR: 1.138, 95% CI: 1.028–1.260, p = 0.013) were the two significant factors associated with the euploidy probabilities. The Cochran-Armitage trend test demonstrated that the blastocyst euploidy percentage increased progressively with the increasing hCG-OPU interval in normal responders (p = 0.006) and advanced maternal age (age ≥38 years; p = 0.020) groups. In normal responders, the euploidy rate was highest in the 38–39 h interval (43.1%, 47/109). In contrast, the euploidy rate was lowest in the 34–35 h interval (28.7%, 29/105). In conclusion, the present study demonstrated that at an hCG-OPU interval between 34–39 h, the longer the hCG-OPU interval, the higher the probability of euploidy for blastocysts.

Embryo morphokinetics is potentially associated with clinical outcomes of single-embryo transfers in preimplantation genetic testing for aneuploidy cycles

RESEARCH QUESTION

Are the morphokinetics of euploid blastocysts evaluated by a generally applicable algorithm associated with the clinical outcomes of single-embryo transfer (SET)?

DESIGN

Time-lapse microscopy was used to compare morphokinetic variables between expanded blastocysts derived from preimplantation genetic testing for aneuploidy cycles using high-resolution next-generation sequencing (hr-NGS). The clinical efficacy of the morphokinetic algorithm KIDScore D5 was evaluated after euploid SET.

RESULTS

Compared with euploid blastocysts, low-level mosaic blastocysts presented comparable morphokinetic and morphological features. However, high-level mosaic blastocysts exhibited significant delays in t5 (median 51.9 h post insemination (hpi), P = 0.034) (where t is the time for the embryo to reach the specific stage in hours after ICSI or conventional IVF) and t8 (median 58.6 hpi, P = 0.032) accompanied by a prolonged time period for the third cell cycle (median 14.7 h, P = 0.012). A significantly higher incidence (P = 0.011) of multinucleation indicated a susceptibility of high-level mosaic blastocysts to mitotic errors. Only a delay in the time for the embryo to reach the full blastocyst stage (median 106.0 hpi, P = 0.039) was revealed in aneuploid blastocysts, reflecting the reduced formation of good-quality blastocysts (42.6% versus 65.7%, P < 0.001). Euploid blastocysts with specific morphokinetic characteristics were graded using the KIDScore D5 algorithm. Grade C embryos achieved significantly lower rates of clinical pregnancy, implantation and ongoing pregnancy (25%, 25% and 10%, respectively) compared with the grade A (76.2%, 79.4% and 68.3%, respectively) or grade B (62.5%, 66.7% and 62.5%, respectively) embryos (P = 0.0171 to <0.0001).

CONCLUSIONS

Although morphokinetic features appear dissimilar in embryos with different diploid-aneuploid mosaic levels, predicting chromosomal abnormalities using morphokinetics alone is still insufficient. When combined with hr-NGS, use of the generally applicable KIDScore D5 algorithm has the potential to discriminate euploid blastocysts with different developmental competence.

Effects of growth hormone plus gonadotropins on controlled ovarian stimulation in infertile women of advanced age, poor responders, and previous in vitro fertilization failure patients

OBJECTIVE

To investigate the effects of growth hormone (GH) cotreatment in ovarian stimulation in infertile women of advanced age, poor responders, and patients with one or more previous IVF treatment failures.

MATERIALS AND METHODS

We conducted a retrospective observational study of 436 patients undergoing GH cotreatment in ovarian stimulation. The first arm included 134 infertile women of advanced age. The second arm included 236 patients with one or more IVF previous treatment failures, and the third arm included 66 younger poor responders. Main outcome measures were the number of oocytes and embryos, quality of embryos, and implantation and pregnancy rates.

RESULTS

In infertile women of advanced age, GH plus ovarian stimulation yielded no statistical differences in the numbers of oocytes and embryos, quality of embryo, and rates of implantation and pregnancy. In the second arm, the mature oocyte number (8.2 vs. 6.8), implantation rate (16.1% vs. 0%), and pregnancy rate (33.9% vs. 0%) in the GH cotreatment group differed significantly from those in the control group; the rate of good-quality embryos in the GH cotreatment group improved from 35.5% ± 31.1%-41.4% ± 30.6% in this arm. Similar results were observed in the third arm; in this arm, the clinical pregnancy rate was 30.3% in the GH cotreatment group and 6.1% in the control group.

CONCLUSION

No significant differences were observed in infertile women of advanced age, which may be due to the low GH dose. The GH adjuvant therapy for patients with one or more previous IVF treatment failures and for poor responders significantly improved the oocyte and embryo numbers as well as implantation and pregnancy rates.

Optimal timing of blastocyst vitrification after trophectoderm biopsy for preimplantation genetic screening

Is the timing of vitrification after trophectoderm (TE) biopsy associated with successful implantation and pregnancy after the embryo transfer of blastocysts subjected to preimplantation genetic screening (PGS)? In this retrospective cohort study, 1329 blastocysts from 223 patients were subjected to TE biopsy for performing array comparative genomic hybridization (CGH) tests. The PGS and frozen blastocyst transfer (FET) cycles were performed from December 2012 to May 2015. Only the good quality and expanded blastocysts on day 5 or 6 were selected for biopsy. After TE biopsy, the re-expansion grades relative to the original blastocoel were (1) collapsed blastocysts (CB), (2) 3/4 re-expansion but not full expansion (RE), and (3) full re-expansion or hatching (FE). All biopsied blastocysts were subjected to vitrification within 0.5-6 h after biopsy; the time intervals between TE biopsy and vitrification and the expansion grades at the time of vitrification were recorded. By combining two factors, namely the expansion grades and culture intervals between biopsy and vitrification, the patients were further divided into four groups, namely CB with a < 3 h culture interval (n = 34 cycles, Group I), RE and FE blastocysts with a < 3 h culture interval (n = 10 cycles, Group II); CB blastocysts with a ≥ 3 h culture interval (n = 6 cycles, Group III); and RE or FE blastocysts with a ≥ 3 h culture interval (n = 173 cycles, Group IV). The implantation (63.7%, 179/281) and clinical pregnancy (74.0%, 128/173) rates in Group IV were significantly higher than those in Group I (45.3%, 24/53; 50.0%, 17/34; P = 0.012 and 0.005, respectively). According to our findings, optimal vitrification timing > 3 hours to enable blastocysts to reach RE or FE provides improved implantation and pregnancy rates after FET.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03065114.

Requirement of Leukemia Inhibitory Factor or Epidermal Growth Factor for Pre-Implantation Embryogenesis via JAK/STAT3 Signaling Pathways

Leukemia inhibitory factor (LIF) plays a key role in the survivability of mouse embryos during pre-implantation. In this study, we verified the role of LIF by detecting gene expression in morula stage embryos through DNA microarray. Our results showed that LIF knockdown affected expression of 369 genes. After LIF supplementation, the epidermal growth factor (EGF) is most affected by LIF expression. To observe the correlation between LIF and EGF, the LIF knockdown embryos were supplemented with various growth factors, including LIF, EGF, GM-CSF, TGF, and IGF II. Only LIF and EGF caused the rate of blastocyst development to recover significantly from 52% of control to 83% and 93%, respectively. All of the variables, including the diameter of blastocysts, the number of blastomeres, and cells in ICM and TE, were almost restored. Moreover, EGF knockdown also impaired blastocyst development, which was reversed by LIF or EGF supplementation. The treatment with various signaling suppressors revealed that both EGF and LIF promoted embryonic development through the JAK/STAT3 signaling pathway. These data suggest that the EGF and LIF can be compensatory to each other during early embryonic development, and at least one of them is necessary for sustaining the normal development of pre-implantation embryos.

Essential versus accessory aspects of cell death: recommendations of the NCCD 2015

Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as ‘accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. ‘Regulated cell death' (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death.

Prerequisite OCT4 Maintenance Potentiates the Neural Induction of Differentiating Human Embryonic Stem Cells and Induced Pluripotent Stem Cells

Establishing an efficient differentiation procedure is prerequisite for the cell transplantation of pluripotent stem cells. Activating fibroblast growth factor (FGF) signals and inhibiting the activin/nodal pathway are both conserved principles to direct the neural induction (NI) of developing embryos and human embryonic stem cells (hESCs). Wnt signal and OCT4 expression are critical for the hESC pluripotency; however, their roles in cell differentiation are largely unclear. We demonstrate that in the presence of FGF2 and activin inhibitor SB431542, applying a small-molecule Wnt agonist, BIO, efficiently and rapidly steers the NI of all our tested hESCs. A human induced pluripotent stem cell (iPSC), which is refractory for efficient neural conversion by FGF2, effectively differentiated to SOX1(+) cells after the BIO/SB431542/FGF2 treatment. In addition, BIO promoted cell survival and transiently sustained OCT4 expression at the early NI stage with FGF2 and SB431542. Interestingly, at the late NI stage, the OCT4 level rapidly declined in the treated hESCs and consequently initiated the formation of neural rosettes with forebrain neuron characteristics. This study illustrates the distinct effects of Wnt activation on maintaining pluripotency and committing neural lineages at the early and late NI stages of hESCs and iPSCs, respectively.

Association of creatin kinase B and peroxiredoxin 2 expression with age and embryo quality in cumulus cells

PURPOSE

the purpose of this study was to identify age-related oocyte or embryo markers suitable for non-invasive analysis, as women over 38 years of age experience diminished pregnancy and ovulation rates.

METHODS

we used real-time quantitative PCR to examine the gene expression profiles in cumulus cells acquired from older and younger age groups. We selected 11 genes involved in three functions that directly affect cellular aging: cell cycle control, apoptosis, and metabolism.

RESULTS

CKB and PRDX2 were up-regulated in women older than 38 years, and the expression of these genes in cumulus cells was associated with embryo quality. In good-quality embryos, CKB expression was higher in the cumulus cells acquired from both older and younger age groups than in poor-quality embryos.

CONCLUSIONS

these potential relationships among cumulus cell gene expression, oocyte quality, and age may expand our understanding of oogenesis and embryo development. CKB and PRDX2 may serve as biomarkers or therapeutic targets for the developmental potential of oocytes.

Granzyme G is expressed in the two-cell stage mouse embryo and is required for the maternal-zygotic transition

Background

Detailed knowledge of the molecular and cellular mechanisms that direct spatial and temporal gene expression in pre-implantation embryos is critical for understanding the control of the maternal-zygotic transition and cell differentiation in early embryonic development. In this study, twenty-three clones, expressed at different stages of early mouse development, were identified using differential display reverse transcription polymerase chain reaction (DDRT-PCR). One of these clones, which is expressed in 2-cell stage embryos at 48 hr post-hCG injection, shows a perfect sequence homology to the gene encoding the granzyme G protein. The granzyme family members are serine proteases that are present in the secretory granules of cytolytic T lymphocytes. However, the pattern of granzyme G expression and its function in early mouse embryos are entirely unknown.

Results

Upon the introduction of an antisense morpholino (2 mM) against granzyme G to knock-down endogenous gene function, all embryos were arrested at the 2- to 4-cell stages of egg cleavage, and the de novo synthesis of zygotic RNAs was decreased. The embryonic survival rate was dramatically decreased at the late 2-cell stage when serine protease-specific inhibitors, 0.1 mM 3,4-dichloroisocoumarin (3,4-DCI), and 2 mM phenyl methanesulphonyl fluoride (PMSF), were added to the in vitro embryonic culture medium. Survival was not affected by the addition of 0.5 mM EDTA, a metalloproteinase inhibitor.

Conclusion

We characterized for the first time the expression and function of granzyme G during early stage embryogenesis. Our data suggest that granzyme G is an important factor in early mouse embryonic development and may play a novel role in the elimination of maternal proteins and the triggering of zygotic gene expression during the maternal-zygotic transition.

A novel, high conductance channel of mitochondria linked to apoptosis in mammalian cells and Bax expression in yeast

During apoptosis, proapoptotic factors are released from mitochondria by as yet undefined mechanisms. Patch-clamping of mitochondria and proteoliposomes formed from mitochondrial outer membranes of mammalian (FL5.12) cells has uncovered a novel ion channel whose activity correlates with onset of apoptosis. The pore diameter inferred from the largest conductance state of this channel is approximately 4 nm, sufficient to allow diffusion of cytochrome c and even larger proteins. The activity of the channel is affected by Bcl-2 family proteins in a manner consistent with their pro- or antiapoptotic properties. Thus, the channel activity correlates with presence of proapoptotic Bax in the mitochondrial outer membrane and is absent in mitochondria from cells overexpressing antiapoptotic Bcl-2. Also, a similar channel activity is found in mitochondrial outer membranes of yeast expressing human Bax. These findings implicate this channel, named mitochondrial apoptosis-induced channel, as a candidate for the outer-membrane pore through which cytochrome c and possibly other factors exit mitochondria during apoptosis.

BCL-2, BCL-X(L) sequester BH3 domain-only molecules preventing BAX- and BAK-mediated mitochondrial apoptosis

Critical issues in apoptosis include the importance of caspases versus organelle dysfunction, dominance of anti- versus proapoptotic BCL-2 members, and whether commitment occurs upstream or downstream of mitochondria. Here, we show cells deficient for the downstream effectors Apaf-1, Caspase-9, or Caspase-3 display only transient protection from "BH3 domain-only" molecules and die a caspase-independent death by mitochondrial dysfunction. Cells with an upstream defect, lacking "multidomain" BAX, BAK demonstrate long-term resistance to all BH3 domain-only members, including BAD, BIM, and NOXA. Comparison of wild-type versus mutant BCL-2, BCL-X(L) indicates these antiapoptotics sequester BH3 domain-only molecules in stable mitochondrial complexes, preventing the activation of BAX, BAK. Thus, in mammals, BH3 domain-only molecules activate multidomain proapoptotic members to trigger a mitochondrial pathway, which both releases cytochrome c to activate caspases and initiates caspase-independent mitochondrial dysfunction.

Aven, a novel inhibitor of caspase activation, binds Bcl-xL and Apaf-1

Bcl-x(L), an antiapoptotic Bcl-2 family member, is postulated to function at multiple stages in the cell death pathway. The possibility that Bcl-x(L) inhibits cell death at a late (postmitochondrial) step in the death pathway is supported by this report of a novel apoptosis inhibitor, Aven, which binds to both Bcl-x(L) and the caspase regulator, Apaf-1. Identified in a yeast two-hybrid screen, Aven is broadly expressed and is conserved in other mammalian species. Only those mutants of Bcl-x(L)that retain their antiapoptotic activity are capable of binding Aven. Aven interferes with the ability of Apaf-1 to self-associate, suggesting that Aven impairs Apaf-1-mediated activation of caspases. Consistent with this idea, Aven inhibited the proteolytic activation of caspases in a cell-free extract and suppressed apoptosis induced by Apaf-1 plus caspase-9. Thus, Aven represents a new class of cell death regulator.

Modulation of cell death by Bcl-XL through caspase interaction

The caspases are cysteine proteases that have been implicated in the execution of programmed cell death in organisms ranging from nematodes to humans. Many members of the Bcl-2 family, including Bcl-XL, are potent inhibitors of programmed cell death and inhibit activation of caspases in cells. Here, we report a direct interaction between caspases and Bcl-XL. The loop domain of Bcl-XL is cleaved by caspases in vitro and in cells induced to undergo apoptotic death after Sindbis virus infection or interleukin 3 withdrawal. Mutation of the caspase cleavage site in Bcl-XL in conjunction with a mutation in the BH1 homology domain impairs the death-inhibitory activity of Bcl-XL, suggesting that interaction of Bcl-XL with caspases may be an important mechanism of inhibiting cell death. However, once Bcl-XL is cleaved, the C-terminal fragment of Bcl-XL potently induces apoptosis. Taken together, these findings indicate that the recognition/cleavage site of Bcl-XL may facilitate protection against cell death by acting at the level of caspase activation and that cleavage of Bcl-XL during the execution phase of cell death converts Bcl-XL from a protective to a lethal protein.

Conversion of Bcl-2 to a Bax-like death effector by caspases

Caspases are a family of cysteine proteases implicated in the biochemical and morphological changes that occur during apoptosis (programmed cell death). The loop domain of Bcl-2 is cleaved at Asp34 by caspase-3 (CPP32) in vitro, in cells overexpressing caspase-3, and after induction of apoptosis by Fas ligation and interleukin-3 withdrawal. The carboxyl-terminal Bcl-2 cleavage product triggered cell death and accelerated Sindbis virus-induced apoptosis, which was dependent on the BH3 homology and transmembrane domains of Bcl-2. Inhibitor studies indicated that cleavage of Bcl-2 may further activate downstream caspases and contribute to amplification of the caspase cascade. Cleavage-resistant mutants of Bcl-2 had increased protection from interleukin-3 withdrawal and Sindbis virus-induced apoptosis. Thus, cleavage of Bcl-2 by caspases may ensure the inevitability of cell death.

Herpesvirus saimiri encodes a functional homolog of the human bcl-2 oncogene

Here we demonstrate that open reading frame 16 (ORF16) of the oncogenic herpesvirus saimiri protects cells from heterologous virus-induced apoptosis. The BH1 and BH2 homology domains are highly conserved in ORF16, and ORF16 heterodimerizes with Bcl-2 family members Bax and Bak. However, ORF16 lacks the core sequence of the conserved BH3 homology domain, suggesting that this region is not essential for anti-apoptotic activity. Conservation of a functional bcl-2 homolog among gammaherpesviruses suggests that inhibition of programmed cell death is important in the biology of these viruses.

A Bcl-2 homolog encoded by Kaposi sarcoma-associated virus, human herpesvirus 8, inhibits apoptosis but does not heterodimerize with Bax or Bak

The Bcl-2 protein family is characterized by the ability to modulate cell death, and members of this family share two highly conserved domains called Bcl-2 homology 1 (BH1) and 2 (BH2) which have been shown to be critical for the death-repressor activity of Bcl-2 and Bcl-xL. Through sequence analysis we identified a novel viral Bcl-2 homolog, designated KSbcl-2, from human herpesvirus 8 (HHV8) or Kaposi sarcoma-associated herpesvirus. The overall amino acid sequence identity between KSbcl-2 and other Bcl-2 homologs is low (15-20%) but concentrated within the BH1 and BH2 regions. Overexpression of KSbcl-2 blocked apoptosis as efficiently as Bcl-2, Bcl-xL, or another viral Bcl-2 homolog encoded by Epstein-Barr virus, BHRF1. Interestingly, KS-bcl-2 neither homodimerizes nor heterodimerizes with other Bcl-2 family members, suggesting that KSbcl-2 may have evolved to escape any negative regulatory effects of the cellular Bax and Bak proteins. Furthermore, the herpesvirus Bcl-2 homologs including KSbcl-2, BHRF1, and ORF16 of herpesvirus saimiri contain poorly conserved Bcl-2 homology 3 (BH3) domains compared with other mammalian Bcl-2 homologs, implying that BH3 may not be essential for anti-apoptotic function. This is consistent with our observation that amino acid substitutions within the BH3 domain of Bcl-xL had no effect on its death-suppressor activity.

Bax-independent inhibition of apoptosis by Bcl-XL

The Bcl-2-related protein, Bcl-XL, has been shown to block apoptosis induced by a variety of stimuli and to be a stronger protector against apoptosis than Bcl-2 under certain circumstances. Using site-specific mutagenesis, we show here that the amino-acid residues critical for protection of cells by Bcl-XL against Sindbis virus-induced apoptosis are clustered within the Bcl-2-homology regions 1 and 2 (BH1 and BH2 regions). The residues necessary for Bcl-XL function are not identical to those required for Bcl-2 function. Although it has been suggested that heterodimerization between Bcl-XL and Bax is essential for the anti-death activity of Bcl-XL (refs 7,8), our results suggest that the interaction with Bax is not required for Bcl-XL to exert its death-repressing activity. Specific mutations that disrupt the ability of Bcl-XL to interact with Bax or Bak still preserve 70-80% of the anti-death activity of wild-type Bcl-XL.

Calmodulin-dependent protein kinases in rat glioblastoma

The mitogenic activity of several growth factors is mediated by calcium-dependent signal transduction. Calmodulin (CaM) binding proteins such as CaM-dependent protein kinases are important components of this pathway and may be altered in diseases characterized by abnormal cell growth. CaM kinase II is believed to regulate the phosphorylation of microtubular-associated proteins and control the initiation of DNA synthesis. Furthermore, drugs that inhibit CaM-mediated signal transduction also inhibit cellular proliferation and are cytotoxic to numerous malignant cell lines, including those established from malignant gliomas. Yet, little is known about CaM-dependent protein kinases in these tumors. Therefore, we have investigated the activity and distribution of CaM-dependent protein kinase II in normal and malignant glial tissues, a kinase believed to play a critical role in cell cycle regulation. C6 and 9L cells contained kinase activities that were activated by Ca2+/CaM and inhibited by trifluoperazine. Tissue extracts from these cell lines and from rat brain white matter phosphorylated exogenous synapsin I in a pattern consistent with the presence of CaM kinase II activity as determined by phosphopeptide mapping. CaM kinase II activity was confirmed using a specific peptide substrate and inhibitor. An unexpected finding was that glioma lines, but not rat brain white matter, also contained a CaM-dependent protein kinase detected by the phosphorylation of a M(r) 100,000 protein, subsequently identified as elongation factor 2, the only known substrate for CaM kinase III.(ABSTRACT TRUNCATED AT 250 WORDS)

Phosphorylation of elongation factor 2 in normal and malignant rat glial cells

Certain calmodulin (CaM)-dependent protein kinases phosphorylate substrates have been implicated in regulating cellular proliferation. In this study, CaM-dependent phosphorylation has been examined in normal and tumor tissue from rat brain to determine whether differences exist. Using in vitro phosphorylation reactions, we compared endogenous substrates for Ca2+/CaM-dependent protein kinases in rat brain white matter (RBWM), a tissue rich in normal glia, to those of C6 rat glioma cells. A major phosphoprotein having a M(r) of 100,000 was observed in proliferating C6 cells that was not present in RBWM or in nonproliferating cells. Phosphorylation was stimulated by Ca2+ and CaM and inhibited by trifluoperazine. An antibody to elongation factor 2 (EF-2) immunoprecipitated the M(r) 100,000 protein from C6 cells. EF-2 was present in RBWM but was not phosphorylated. Homogenates of RBWM did not phosphorylate exogenous EF-2, which suggested the absence of CaM kinase III activity in normal glial tissue. Furthermore, the addition of purified, exogenous CaM kinase III to homogenates of RBWM resulted in EF-2 phosphorylation. These data demonstrate that a basal level of EF-2 phosphorylation exists in proliferating glioma cells that is markedly diminished or absent in normal glial tissue and is due to the activity of CaM kinase III.

Persistence of intestinal antibody response to heterologous rotavirus infection in a murine model beyond 1 year

We used an ELISPOT (enzyme-linked immunosorbent spot) assay to quantitate the long-term rotavirus-specific intestinal antibody response in a murine model. The frequency of murine intestinal antibody-secreting cells (ASCs) was followed for a period of 1 year after a single dose of rhesus rotavirus (10(6) PFU) was administered at 10 days of age. Some animals were boosted at that time with a second dose. One year after infection, virus-specific ASCs declined from acute-phase levels, but they were still present at significant levels (1.32 x 10(4) virus-specific ASCs per 10(6) intestinal mononuclear cells; approximately 17% of the previously reported response at 1 month after infection). A booster dose 1 year after the primary infection produced a 100% increase in virus-specific ASCs but did not restore the response to that of the primary infection.

"Postgastrectomy" bezoar secondary to gastric cancer

Phytobezoars are frequently associated with partial gastrectomy and are generally considered benign. However, we report two patients who developed a gastric bezoar due to malignancy at the anastomotic site. Development of intragastric bezoar may be an indication of neoplastic growth sufficient to obstruct a small gastric outlet. Consequently, we conclude that endoscopic or surgical evaluation of the anastomotic site is necessary in patients who develop bezoars after gastric surgery.

Recombinant baculovirus-expressed rotavirus protein (VP4) in an ELISPOT assay of antibody secretion

Studies on the protein specificity of the intestinal antibody response to rotavirus infection have been hampered by lack of antigenically conserved isolated proteins to serve as antigens in immunochemical assays. In this report, the use of an antigenically conserved baculovirus-expressed rotavirus protein (VP4) as a capture antigen in the ELISPOT assay is described. Anti-VP4 antibody-secreting hybridoma cells are used as a test population to show that expressed VP4 as the capture antigen detects numbers of antibody secreting cells comparable to intact rotavirus particles. Hybridoma cells specific for other rotavirus proteins are used to ensure the specificity of the expressed VP4 in the assay. The flexibility and ease of use of a recombinant expressed protein product as a capture antigen in this assay dramatically enhances the ability to quantitate intestinal antibody responses to specific viral proteins.

Effects of bradykinin on intracellular calcium regulation in human ciliated airway epithelium

The Ca(2+)-mobilizing action of bradykinin (BK) was investigated in ciliated human nasal epithelial (HNE) cells utilizing fura-2 fluorescence and microspectrofluorimetry. In ciliated cells, basal intracellular Ca2+ concentration ([Ca2+]i) was 123 +/- 3 nM (n = 142). BK caused [Ca2+]i to increase (spike) rapidly (within 6 s) to greater than 550 nM by releasing Ca2+ from intracellular pools. The mean effective dose for the process was 1.5 x 10(-7) M BK. The spike was due to the activation of a beta 2-receptor. The spike was unaffected by inhibitors of either cyclooxygenase or voltagegated Ca2+ channels. After the spike, [Ca2+]i decreased to a plateau level (120-250 nM). This plateau persisted (up to 10 min) until the addition of La3+ (0.3 x 10(-3) M) or until the removal of either extracellular Ca2+ or the agonist. No changes in adenosine 3',5'-cyclic monophosphate (cAMP) levels were detected after BK exposure. Additional studies revealed that indomethacin (10(-6) M), isoproterenol (10(-5) M), forskolin (10(-5) M), and dibutyryl cAMP (1 mM) had no effect on [Ca2+]i in ciliated HNE cells. In summary, these data suggest that 1) BK mediates both Ca2+ release from internal pools and Ca2+ entry into the cytoplasm from the extracellular space, and 2) unlike the response to cultured dog airway epithelia, the release of [Ca2+]i in response to BK does not appear to be mediated by either cyclooxygenase pathway or adenylate cyclase-cAMP systems.

Murine intestinal antibody response to heterologous rotavirus infection

Rotavirus is the most important worldwide cause of severe gastroenteritis. Extensive efforts have been devoted to the design of a vaccine that will prevent disease, but development of a more effective vaccine strategy may require progress in the understanding of the mucosal immune response to replicating viral antigens. In this article, we report the characterization of the intestinal antibody response of a murine model to heterologous infection with the rhesus rotavirus vaccine strain. We have adapted the enzyme-linked immunospot assay to measure this response without the difficulties associated with measurement of antibodies in intestinal contents or the artifacts associated with culturing of lymphocytes. The predominant response in terms of antibody-secreting cells (ASC) is seen in the small intestine lamina propria, which can be measured within 4 days of infection, peaks 3 weeks after infection, and remains near that level for longer than 8 weeks. The magnitude of the immunoglobulin A (IgA) cell response is approximately 10 times greater than the intestinal IgG cell response, and IgM cells are rare. Virus-specific ASC constitute approximately 50% of all ASC in the gut at the peak of the virus-specific response. This response is considerably greater than responses to nonreplicating mucosal antigens measured by similar techniques. Enteral infection engenders minimal virus-specific ASC response in the spleen. Rhesus rotavirus-specific enzyme-linked immunosorbent assay and neutralization assays of serum and intestinal contents did not correlate with virus-specific ASC response.

VP4-specific intestinal antibody response to rotavirus in a murine model of heterotypic infection

We have adapted a murine model of heterotypic rotavirus infection for the purpose of evaluating the intestinal antibody response to an infection that mimics human vaccination. Neonatal mice were infected with the rhesus rotavirus (RRV). The enzyme-linked immunospot assay was used in order to avoid common artifacts in the quantitation of intestinal immune responses inherent in measurements of luminal or serum immunoglobulins and to obtain easily quantifiable data in a flexible and convenient format. Functionally active lymphocytes were harvested from the spleen, small intestinal lamina propria, Peyer's patches, and mesenteric lymph nodes and processed into single-cell suspensions. Antibody-secreting cells (ASC) were quantitated from 5 to 50 days after infection for total, RRV-specific, baculovirus-expressed VP4-specific, and single-shell RRV-specific ASC secreting either immunoglobulin G (IgG), IgM, or IgA. The response to VP4 constituted less than 1.5% of the total virus-specific response, which was located almost exclusively in the gut and was 90% IgA. Intestinal ASC were directed overwhelmingly toward proteins incorporated in the single-shell particle, predominantly VP2 and VP6. We conclude that the antibody response to VP4, thought to be the site of the important neutralization sites conserved among several rotavirus serotypes, is an extremely small portion of the overall antibody response in the intestinal tract.

Multiple gastrointestinal tract diverticula

Simultaneous occurrence of gastrointestinal diverticula at multiple sites in a single patient is unusual. We report a patient with a Zenker's, a mid-esophageal, a gastric, and multiple colonic diverticula. The presence of multifocal gastrointestinal diverticula suggests as one possible etiology congenital weaknesses in the bowel wall, since esophageal manometry and histology of a resected diverticulum did not reveal any abnormalities other than gastroesophageal reflux.

Chloride secretory response of cystic fibrosis human airway epithelia. Preservation of calcium but not protein kinase C- and A-dependent mechanisms

Because the defect in Cl- secretion exhibited by cystic fibrosis (CF) epithelia reflects regulatory rather than conductive abnormalities of an apical membrane Cl- channel, we investigated the role of different regulatory pathways in the activation of Cl- secretion in freshly excised normal and CF nasal epithelia mounted in Ussing chambers. A beta agonist (isoproterenol [ISO]), a Ca2+ ionophore (A23187), and a phorbol ester (PMA) were all effective Cl- secretagogues in normal human nasal epithelia. Agonist addition studies indicated that ISO and PMA but not A23187 may share a common regulatory pathway. In contrast, only A23187 induced Cl- secretion in CF epithelia. Bradykinin raised cytosolic Ca2+ and induced Cl- secretion in both normal and CF tissues, indicating that receptor gated Ca2+ dependent Cl- secretory mechanisms were preserved in CF. The defective Cl- secretory response in CF epithelia to ISO and PMA did not reflect abnormalities in cAMP-dependent (A) and phospholipid Ca2+-dependent (C) kinase activities. We conclude that (a) a Ca2+-sensitive mechanism for regulating Cl- secretion is maintained in CF airway epithelia, and (b) a regulatory pathway shared by two distinct protein kinases is defective in CF, indicating that the CF genetic lesion is not tightly coupled to a single (e.g., cAMP dependent) regulatory mechanism.