Attachment of blastocysts to lens capsule: A model system for trophoblast-epithelial cell interaction on a natural basement membrane

Summary The bovine lens capsule has previously been shown to provide an optimal surface for the examination of epithelial cell interaction with a basement membrane. This native substrate has been used to investigate some initial aspects of attachment of mouse blastocysts and trophoblastic cellular outgrowth. Mouse blastocysts were presented to the cell-free humoral side of the anterior lens capsule, incubated for 72 h, and examined by scanning and transmission electron microscopy. Blastocysts hatch and attach from their zonae pellucidae by 30 h. Trophoblastic cells proliferate rapidly in a coronal direction, display extensive surface microvilli, and advance by the extension of numerous filipodia, many of which terminate with bulbous projections. These projections were shown by transmission electron microscopy to contain numerous vacuoles and polysomes. To simulate further the initial blastocyst-uterine interaction, a suspension of lens epithelial cells was introduced to the capsule and permitted to form a monolayer prior to the addition of the blastocysts. At 72 h the monolayer of lens cells remained intact. We observed that: a) lens cells appear to recede from the advancing trophoblastic cells, and b) trophoblastic cells extend beneath the monolayer of lens cells and thereby dislodge the cells from the lens capsule substrate. No infiltration of the capsule by the advancing trophoblastic cells was observed. The lens capsule appears to offer a promising system for the study of trophoblast-epithelial cell interaction on a natural basement membrane.     

Transforming growth factor-β1 in reproduction

Expression patterns of TGF-βs during embryogenesis and in adult reproductive organs, as well as the activities of these molecules in in vitro assays of biological processes relating to reproduction and development, have suggested that TGF-βs may play a role in both reproductive function and embryonic development. To investigate the function of TGF-β1 in vivo, the murine TGF-β1 gene was disrupted by gene targeting, and animals that lacked TGF-β1 activity were generated. Homozygous mutant animals were obtained which exhibited a multifocal inflammatory disease. However, the observed numbers of homozygous mutant offspring were less than expected, suggesting the occurrence of some type of prenatal lethality. This paper reviews the proposed role of the TGF-βs in reproductive and developmental processes and discusses observations obtained from the TGF-β1 gene-targeting experiments as they relate to these processes. © 1994 Wiley-Liss, Inc.     

Population-specific material properties of the implantation site for transcatheter aortic valve replacement finite element simulations

Patient-specific computational models are an established tool to support device development and test under clinically relevant boundary conditions. Potentially, such models could be used to aid the clinical decision-making process for percutaneous valve selection; however, their adoption in clinical practice is still limited to individual cases. To be fully informative, they should include patient-specific data on both anatomy and mechanics of the implantation site. In this work, fourteen patient-specific computational models for transcatheter aortic valve replacement (TAVR) with balloon-expandable Sapien XT devices were retrospectively developed to tune the material parameters of the implantation site mechanical model for the average TAVR population.Pre-procedural computed tomography (CT) images were post-processed to create the 3D patient-specific anatomy of the implantation site. Balloon valvuloplasty and device deployment were simulated with finite element (FE) analysis. Valve leaflets and aortic root were modelled as linear elastic materials, while calcification as elastoplastic. Material properties were initially selected from literature; then, a statistical analysis was designed to investigate the effect of each implantation site material parameter on the implanted stent diameter and thus identify the combination of material parameters for TAVR patients.These numerical models were validated against clinical data. The comparison between stent diameters measured from post-procedural fluoroscopy images and final computational results showed a mean difference of 2.5 ± 3.9%. Moreover, the numerical model detected the presence of paravalvular leakage (PVL) in 79% of cases, as assessed by post-TAVR echocardiographic examination.The final aim was to increase accuracy and reliability of such computational tools for prospective clinical applications.     

Exosomal ANXA2 derived from ovarian cancer cells regulates epithelial-mesenchymal plasticity of human peritoneal mesothelial cells

Ovarian cancer, one of the malignant gynaecological tumours with the highest mortality rate among female reproductive system, is prone to metastasis, recurrence and chemotherapy resistance, causing a poor prognosis. Exosomes can regulate the epithelial-mesenchymal plasticity of tumour cells, remodel surrounding tumour microenvironment, and affect tumour cell proliferation, invasion and metastasis. However, the function and mechanism of exosomes in the intraperitoneal implantation of ovarian cancer remain unclear. In this study, exosomal annexin A2 (ANXA2) derived from ovarian cancer cells was co-cultured with human peritoneal mesothelial (HMrSV5) cells; functional experiments were conducted to explore the effects of exosomal ANXA2 on the biological behaviour of HMrSV5 and the related mechanisms. This study showed that ANXA2 in ovarian cancer cells can be transferred to HMrSV5 cells through exosomes, exosomal ANXA2 can not only promote the migration, invasion and apoptosis of HMrSV5 cells, but also regulates morphological changes and fibrosis of HMrSV5 cells. Furthermore, ANXA2 promotes the mesothelial-mesenchymal transition (MMT) and degradation of the extracellular matrix of HMrSV5 cells through PI3K/AKT/mTOR pathway, finally affects pre-metastasis microenvironment of ovarian cancer, which provides a new theoretical basis for the mechanism of intraperitoneal implantation and metastasis of ovarian cancer.     

Leukemia inhibitory factor and interleukin-11: Critical regulators in the establishment of pregnancy

Blastocyst implantation into a receptive endometrium is critical to the establishment of pregnancy and is tightly regulated by factors within the blastocyst–endometrial micro-environment. Leukemia inhibitory factor (LIF) and interleukin-11 (IL11) have key roles during implantation. Female mice with a null mutation in the LIF or IL11RA gene are infertile due to a complete failure of implantation or a defective differentiation/decidualization response to the implanting blastocyst, respectively. LIF and IL11 deficiency during pregnancy is associated with infertility and miscarriage in women. Numerous cell populations at the maternal–fetal interface are regulated by LIF/IL11 including the endometrial epithelium, decidualizing stroma, placental trophoblasts and leukocytes. This review focuses on the roles of LIF/IL11 during early pregnancy and highlights their potential as contraceptive targets and therapeutic agents for infertility.     

Effect of the “zero” Magnetic Field on Early Embryogenesis in Mice

It was shown that the 250-fold screening of the geomagnetic field (GMF) (“zero” magnetic field with an induction of 0.2?μT) affects early embryogenesis and the reproduction capacity of mice in vivo. Pregnant NMRI mice at the zygote stage placed in this “zero” magnetic field (MF) lost the ability to bear offspring babies although their embryos developed up to the blastocyst stage without any visible deviations from the norm. The abortion of development in the “zero” MF occurred after the exit of the blastocysts from the zona pellicida and invasion into the uterus during implantation. Histological analysis indicates that possible reasons of the abnormalities of postimplantation development are a decrease in the proliferative activity of embryonic cells and the impairment of the interaction between the trophoblast and endometrium, which finally results in the resorption of embryos in the uterus.     

Techniques for Processing Eyes Implanted With a Retinal Prosthesis for Localized Histopathological Analysis

With the recent development of retinal prostheses, it is important to develop reliable techniques for assessing the safety of these devices in preclinical studies. However, the standard fixation, preparation, and automated histology procedures are not ideal. Here we describe new procedures for evaluating the health of the retina directly adjacent to an implant. Retinal prostheses feature electrode arrays in contact with eye tissue. Previous methods have not been able to spatially localize the ocular tissue adjacent to individual electrodes within the array. In addition, standard histological processing often results in gross artifactual detachment of the retinal layers when assessing implanted eyes. Consequently, it has been difficult to assess localized damage, if present, caused by implantation and stimulation of an implanted electrode array. Therefore, we developed a method for identifying and localizing the ocular tissue adjacent to implanted electrodes using a (color-coded) dye marking scheme, and we modified an eye fixation technique to minimize artifactual retinal detachment. This method also rendered the sclera translucent, enabling localization of individual electrodes and specific parts of an implant. Finally, we used a matched control to increase the power of the histopathological assessments. In summary, this method enables reliable and efficient discrimination and assessment of the retinal cytoarchitecture in an implanted eye.     

The ADP-ribosylation factor 1 gene is indispensable for mouse embryonic development after implantation

ADP-ribosylation factor (Arf) 1 is thought to affect the morphologies of organelles, such as the Golgi apparatus, and regulate protein trafficking pathways. Mice have six Arf isoforms. In knockdown experiments with HeLa cells, no single Arf isoform among Arf1–5 is required for organelle morphologies or any membrane trafficking step. This suggests that the cooperation of two or more Arfs is a general feature. Although many cell biological and biochemical analyses have proven the importance of Arf1, the physiological roles of Arf1 in mice remain unknown. To investigate the activity of Arf1 in vivo, we established Arf1-deficient mice. Arf^−/− blastocysts were identified at the expected Mendelian ratio. The appearance of these blastocysts was indistinguishable from that of wild-type and Arf^+/− blastocysts, and they grew normally in an in vitro culture system. However, Arf^−/− embryos were degenerated at E5.5, and none survived to E12.5, suggesting that they died soon after implantation. These data establish for the first time that the Arf1 gene is indispensable for mouse embryonic development after implantation.