Jing-Yi Li

Cardiovascular Dysfunction in Offspring of Ovarian-Hyperstimulated Women and Effects of Estradiol and Progesterone: A Retrospective Cohort Study and Proteomics Analysis

CONTEXT The cardiovascular dysfunction in children born with assisted reproductive technologies has been of great concern. However, the association of ovarian hyperstimulation syndrome (OHSS), a complication of assisted reproductive technologies, with worse cardiovascular functions and underlying mechanism remains unknown. OBJECTIVES The objective of the study was to assess the cardiovascular functions of children born to mothers with OHSS and investigate the underlying regulator(s). DESIGN AND SETTING This was a retrospective cohort recruited in a university hospital. PARTICIPANTS AND METHODS We assessed the cardiovascular functions by Doppler echography in 42 children born to OHSS women, 34 children of mothers with non-OHSS in vitro fertilization, and 48 spontaneously conceived (SC) children (mean age ∼ 4.5 y). Groups were matched for gestational age at delivery and birth weight. An isobaric tag for relative and absolute quantitation-labeled proteomics analysis was performed with another set of umbilical arteries from OHSS and SC pregnancies (n = 3 for both groups). RESULTS Children of OHSS mothers showed a significantly decreased mitral ratio of early to late mitral peak velocities, reduced systolic and diastolic diameters of common carotid arteries, and impaired flow-mediated dilation compared with non-OHSS in vitro fertilization and SC children. Intima-media thickness and arterial stiffness indices were similar in the three groups. In the proteomics study, 1640 proteins were identified from OHSS and SC umbilical arteries, and 40 differentially expressed proteins were selected for further analysis. Estradiol and progesterone were identified as activated upstream regulators. CONCLUSIONS Children born to ovarian-hyperstimulated women displayed cardiovascular dysfunctions. The underlying mechanisms may involve the effects of supraphysiological estradiol and progesterone levels.

Follicle-Stimulating Hormone Induces Postmenopausal Dyslipidemia Through Inhibiting Hepatic Cholesterol Metabolism

CONTEXT The elevated low-density-lipoprotein cholesterol (LDL-C) in menopausal women is associated with higher risks of cardiovascular diseases. OBJECTIVE The aim of this study is to investigate the influence and mechanism by which high postmenopausal FSH levels affect lipid profiles. METHODS The serum FSH and lipid levels were examined in 400 Chinese postmenopausal women. The FSH receptor (FSHR) expression was identified in liver and HepG2 cells by PCR and Western blotting. The effects of FSH on lipid metabolism were confirmed in an ovariectomized mouse model by using GnRH agonist with or without additional FSH to mimic different FSH status. LDL receptor (LDLR), a necessary factor for clearance of LDL-C through endocytosis, was examined by PCR and Western blotting. RESULTS The postmenopausal women with higher serum FSH (≥78.3 IU/L at baseline) had higher serum total cholesterol and LDL-C levels than those women with FSH levels of 40-78.3 IU/L (P < .01). The improvements of total cholesterol and LDL-C levels were more significant in higher FSH women group after treatment with hormone replacement therapy. It was only in the women whose FSH levels were reduced more than 30% after hormone replacement therapy who showed significant improvement of lipid levels. Ovariectomized mice had high serum FSH and lipids levels and reduced hepatic LDLR expression. In HepG2 cells, FSH inhibited the LDLR in a dose- and time-dependent manner, and the FSHR knockdown with specific siRNA reversed the lower LDLR induced by FSH. CONCLUSIONS FSH may interact with its receptors in hepatocytes and reduce LDLR levels, which subsequently attenuates the endocytosis of LDL-C, resulting in an elevated circulating LDL-C level.

In vitro direct organogenesis and regeneration of Medicago sativa.

A rapid and efficient plant regeneration protocol for a wide range of alfalfa genotypes was developed via direct organogenesis. Through a successive excision of the newly developed apical and axillary shoots, a lot of adventitious buds were directly induced from the cotyledonary nodes when hypocotyl of explants were vertically inserted into modified Murashige and Skoog (MS) medium supplemented with 0.025 mg dm−3 thidiazuron (TDZ) and 3 mg dm−3 AgNO3. When the lower part of shoots excised from explants were immersed into the liquid medium with 1.0 mg dm−3 α-naphthaleneacetic acid (NAA) for 2 min, and then transferred to hormone free half-strength MS medium, over 83.3 % of the shoots developed roots, and all plantlets could acclimatize and establish in soil. The protocol has been successfully applied to eight genotypes, with regeneration frequencies ranging from 63.8 to 82.5 %.

A new model for embryo implantation: coculture of blastocysts and Ishikawa cells

Objective: To explore and develop a new in vitro implantation model that reflects the main process of embryo attachment and invasion. Study design: One of the limitations in human embryo implantation research is lack of an available in vitro model that faithfully replicates human embryo–uterine interactions. In the present study, we examined the attachment and invasiveness of blastocysts from mice in Ishikawa cell (IK), a human endometrial cell, to clarify whether this new model is suitable to study implantation of embryos. We used IK and placed it in contact with blastocysts to initiate coculture experiments using a specifically designed medium. The culture medium was composed of Ham F-12/Dulbecco’s modified Eagle medium (1:1), 30% fetal calf serum, 63.5 nmol/L progesterone, 7.14 nmol/L estradiol-17β, 100 mg/ml of insulin, and 20 ng/ml epidermal growth factor. The culture for 24 h clearly demonstrated that embryos were capable of attachment to the IK and displayed partial invasion. Results: Our results showed that embryos attached to the IK and displayed partial invasion after coculture of blastocysts with IK for 48 h. Conclusions: The model is capable of demonstrating the procedure of attachment and invasion of embryo into the endometrial cells and has promises to be used in studies related to early embryo implantation in human endometrium.

Follicle-stimulating hormone promotes age-related endometrial atrophy through cross-talk with transforming growth factor beta signal transduction pathway

It is widely believed that endometrial atrophy in postmenopausal women is due to an age‐related reduction in estrogen level. But the role of high circulating follicle‐stimulating hormone (FSH) in postmenopausal syndrome is not clear. Here, we explored the role of high circulating FSH in physiological endometrial atrophy. We found that FSH exacerbated post‐OVX endometrial atrophy in mice, and this effect was ameliorated by lowering FSH with Gonadotrophin‐releasing hormone agonist (GnRHa). In vitro, FSH inhibited endometrial proliferation and promoted the apoptosis of primary cultured endometrial cells in a dose‐dependent manner. In addition, upregulation of caspase3, caspase8, caspase9, autophagy‐related proteins (ATG3, ATG5, ATG7, ATG12 and LC3) and downregulation of c‐Jun were also observed in endometrial adenocytes. Furthermore, smad2 and smad3 showed a time‐dependent activation in endometrial cells which can be partly inhibited by blocking the transforming growth factor beta receptor II (TβRII). In conclusion, FSH regulated endometrial atrophy by affecting the proliferation, autophagy and apoptosis of endometrial cells partly through activation of the transforming growth factor beta (TGFβ) pathway.

Maternal High Estradiol Exposure is Associated with Elevated Thyroxine and Pax8 in Mouse Offspring

Our previous studies have shown that maternal high estradiol (E2) environment increased the risk of thyroid dysfunction in offspring. However, the mechanism involved remains unexplored. To evaluate the thyroid function of offspring after high E2 exposure and to explore the underlying mechanism, we established a high E2 mouse model of early pregnancy, and detected thyroid hormones of their offspring. In thyroids of offspring, the expressions of Tg, Nis, Tpo, Pax8, and Titf1 and CpG island methylation status of Pax8 and genes involved in methylation were analyzed. We found that thyroxine (T4) and FT4 levels of offspring were obviously increased in the high-E2 group, especially in females. In both 3- and 8-week-old offspring of the high-E2 group, Pax8 was significantly up-regulated in thyroid glands, accompanied by the abnormal CpG island methylation status in the promoter region. Furthermore, Dnmt3a and Mbd1 were obviously down-regulated in thyroids of the high E2 group. Besides, the disturbance of thyroid function in females was more severe than that in males, implying that the effects were related to gender. In summary, our study indicated that maternal high E2 exposure disturbed the thyroid function of offspring through the dysregulation and abnormal DNA methylation of Pax8.

Mechanism underlying the retarded nuclear translocation of androgen receptor splice variants

As shown in our previous study, two alternatively spliced androgen receptor (AR) variants, which are exclusively expressed in the granulosa cells of patients with polycystic ovary syndrome, exhibit retarded nuclear translocation compared with wild-type AR. However, researchers have not yet determined whether these abnormalities correlate with heat shock protein 90 (HSP90) and importin α (the former is a generally accepted co-chaperone of AR, and the latter is a component of classical nuclear import complexes). Here, these two variants were mainly retained in cytoplasm with HSP90 and importin α in the presence of dihydrotestosterone (DHT), and their levels in nucleus were significantly reduced, according to the immunofluorescence staining. The binding affinity of two AR variants for importin α was consistently decreased, while it was increased in WT-AR following DHT stimulation, leading to reduced nuclear import, particularly for the insertion-AR (Ins-AR). However, the binding affinities of two AR variants for HSP90 were increased in the absence of DHT compared with WT-AR, which functioned to maintain spatial structural stability, particularly for the deletion-AR (Del-AR). Therefore, the retarded nuclear translocation of two AR variants is associated with HSP90 and importin α, and the abnormal binding affinities for them play critical roles in this process.

Basonuclin 1 deficiency is a cause of primary ovarian insufficiency

Abstract Primary ovarian insufficiency (POI) leads to infertility and premature menopause in young women. The genetic etiology of this disorder remains unknown in most patients. Using whole exome sequencing of a large Chinese POI pedigree, we identified a heterozygous 5 bp deletion inducing a frameshift in BNC1, which is predicted to result in a non‐sense‐mediated decay or a truncated BNC1 protein. Sanger sequencing identified another BNC1 missense mutation in 4 of 82 idiopathic patients with POI, and the mutation was absent in 332 healthy controls. Transfection of recombinant plasmids with the frameshift mutant and separately with the missense mutant in HEK293T cells led to abnormal nuclear localization. Knockdown of BNC1 was found to reduce BMP15 and p‐AKT levels and to inhibit meiosis in oocytes. A female mouse model of the human Bnc1 frameshift mutation exhibited infertility, significantly increased serum follicle‐stimulating hormone, decreased ovary size and reduced follicle numbers, consistent with POI. We report haploinsufficiency of BNC1 as an etiology of human autosomal dominant POI.

Ovarian stimulation perturbs methylation status of placental imprinting genes and reduces blood pressure in the second generation offspring

OBJECTIVE(S) Assisted reproductive technology (ART) is associated with DNA methylation dysfunction of offspring. However, it is unclear whether ovarian stimulation (OS) is responsible for DNA methylation dysfunction of offspring STUDY DESIGN: We built the first-generation (F1) and second-generation (F2) offspring mice model of ovarian stimulation. Bodyweight of F1 and F2 were measured. Expression levels of several imprinted genes (Impact, H19, Igf2, Plagl1, Mest, and Snrpn) in F1 placenta were tested. Methylation status of Plagl1 and H19 promoters was examined with bisulfite sequencing. Glucose tolerance, blood pressure, and heart rate were evaluated in F2 mice. RESULTS The OS F1 showed elevated bodyweights in the 2nd, 3rd and 4th weeks, but the difference disappeared in the 5th week. Plagl1 was down-regulated in OS F1. Promoters of Plagl1 and H19 were also hypermethylated in OS F1. F2 of OS mice had the similar bodyweight and glucose tolerance compared with the control F2. However, F2 of OS ♂F1+OS♀ F1 showed the decreased systolic pressure, diastolic pressure, and heart rate. CONCLUSIONS Ovarian stimulation perturbs expression levels and methylation status of imprinted genes in offspring. The effect of ovarian stimulation may be passed to F2.

Reduced Intellectual Ability in Offspring of Ovarian Hyperstimulation Syndrome: A Cohort Study

Background Ovarian hyperstimulation syndrome (OHSS), a complication of ovarian stimulation, has various adverse effects on both pregnant women and their offspring. However, whether OHSS will affect intellectual ability in offspring is still unknown. Methods We recruited 86 Chinese children born to OHSS women and 172 children conceived with non-OHSS In Vitro Fertilization (IVF) in this cohort study. Their intellectual ability was assessed according to the Revised Chinese Version of the Wechsler Intelligence Scale for Children (C-WISC). Verbal Intelligence Quotient (VIQ), Performance Intelligence Quotient (PIQ), and Full Intelligence Quotient (FIQ) were calculated. The investigation was registered in Chinese Clinical Trial Registry (ChiCTR-SOC-16009555). Findings OHSS offspring scored less on C-WISC (mean (standard deviation [SD]): (VIQ = 92.7 (14.7), PIQ = 108.9 (13.1), FIQ = 100.6 (13.4)) compared with non-OHSS IVF offspring (VIQ = 100.1 (13.2), PIQ = 113.7 (10.8), FIQ = 107.4 (11.5)). The prevalence of low IQ (< 80) children was 4.7 times higher in OHSS offspring compared with non-OHSS offspring. Maternal estradiol level on hCG administration day was negatively associated with FIQ in offspring. Interpretation OHSS offspring displayed reduced intellectual ability. Prenatal estradiol exposure might be involved in underlying mechanism.