Investigating the Optimal Time for Intrauterine Human Chorionic Gonadotropin Infusion in Order to Improve IVF Outcome: A Systematic Review and Meta-Analysis

An Overview of the Microbiota of the Human Urinary Tract in Health and Disease: Current Issues and Perspectives

This article is intended to deepen our knowledge to date regarding the functions of the resident microbiota/microbiome in the urinary system for human health and disease. First, we sought to report the general characteristics (composition and stability) of the normal urinary system microbiota in the different anatomical sites in relation to some factors such as the effect of age, gender and diet, analyzing in detail the functions and the composition of the microbiota in the light of current knowledge. Several pieces of evidence suggest the importance of preserving the micro-ecosystem of the urinary system, and in some cases their relationship with diseases is important for maintaining human health is well understood. The female and male reproductive microbiota have mainly been studied over the past decade. In the past, the arrest was thought to have taken place in a sterile environment. Microorganisms of the microbiota form biofilms, three-dimensional structures, that differ in the reproductive organs and interact with both gametes and the embryo as well as with maternal tissues. These biofilms from the reproductive system also interact with others, such as that of the gastrointestinal tract. Reduction in its diversity intestinal microbiota can disrupt estrogen metabolism and affect the reproductive microbiota. It is therefore understood that its quantitative and qualitative identification is important for microbiota, but also the study of the structures formed by the microorganisms. A dysbiosis with local or systemic causes can lead to serious diseases. The role of probiotics in maintaining microbial population harmony (eubiosis) and preventing certain pathologies of the urinary and reproductive system was also investigated. A negative variation in the qualitative and quantitative composition of certain strains of microorganisms (dysbiosis) due to local or systemic causes can even lead to serious diseases. The role of probiotics in maintaining the healthy balance of microorganism populations (eubiosis), and thus in the prevention of certain pathologies of the urinary and reproductive system, has also been studied.

Omics insights into extracellular vesicles in embryo implantation and their therapeutic utility

Implantation success relies on intricate interplay between the developing embryo and the maternal endometrium. Extracellular vesicles (EVs) represent an important player of this intercellular signalling through delivery of functional cargo (proteins and RNAs) that reprogram the target cells protein and RNA landscape. Functionally, the signalling reciprocity of endometrial and embryo EVs regulates the site of implantation, preimplantation embryo development and hatching, antioxidative activity, embryo attachment, trophoblast invasion, arterial remodelling, and immune tolerance. Omics technologies including mass spectrometry have been instrumental in dissecting EV cargo that regulate these processes as well as molecular changes in embryo and endometrium to facilitate implantation. This has also led to discovery of potential cargo in EVs in human uterine fluid (UF) and embryo spent media (ESM) of diagnostic and therapeutic value in implantation success, fertility, and pregnancy outcome. This review discusses the contribution of EVs in functional hallmarks of embryo implantation, and how the integration of various omics technologies is enabling design of EV-based diagnostic and therapeutic platforms in reproductive medicine.

Intrauterine Instillation of Human Chorionic Gonadotropin with Intrauterine Insemination Catheter Around the Golden Time of Embryo Transfer Does Not Improve In Vitro Fertilization /Intracytoplasmic Sperm Injection Outcomes in Infertile Women: A Randomized Controlled Trial

BACKGROUND

We set out to explore the effect of intrauterine human chorionic gonadotropin (hCG) instillation by intrauterine insemination (IUI) catheter before embryo transfer (ET) on assisted reproductive technologies (ART) outcomes of infertile women.

METHODS

One hundred women with infertility who were scheduled for in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles were included in the study. They were randomly devoted to two groups: experimental (n= 50) and control (n= 50). In the experimental group, 500 IU hCG passed into the internal cervical orifice via IUI catheter within 15 minutes before the transfer of fresh or vitrified cleavage-stage embryos. The control group underwent the same ET procedure without prior injection of hCG.

RESULTS

None of the outcomes showed a statistically significant difference between the two groups. In the intervention and control groups, respectively, biochemical pregnancies rates were 26% and 18%, implantation rates were 13.5% and 8.6%, clinical pregnancies rates were 22% and 14%, ongoing pregnancies rates were 18% and 14%, and live birth rates were 14% and 12%.

CONCLUSION

Intrauterine injection of hCG via IUI catheter is not recommended in a clinical routine setting at this stage. Future efforts are warranted to further refine the applicability of this modality.

A human chorionic gonadotropin (hCG) delivery platform using engineered uterine exosomes to improve endometrial receptivity

AIM

Endometrial exosomes carry bioactive agents to uterine epithelial cells and trophectoderm to promote implantation. On the other hand, intrauterine administration of human chorionic gonadotropin (hCG) could improve endometrial receptivity. Therefore, we investigated the delivery of hCG to the endometrial cells by uterine exosomes to increase endometrial receptivity.

MAIN METHODS

Exosomes were isolated from uterine fluid and characterized by dynamic light scattering, transmission electron microscopy, and western blotting. The freeze-thaw cycle and sonication methods were used to load hCG into the exosomes. The drug release pattern and uptake of exosomes into the endometrial cells were evaluated. Finally, the influence of hCG loaded-exosomes on the expression of several endometrial receptivity markers was evaluated.

KEY FINDINGS

The isolated uterine fluid exosomes had a cup-shaped or spherical morphology with a mean size of 91.8 nm and zeta potential of -9.75 mV. The average loading capacity of exosomes for hCG was 710.05 ± 73.74 and 245.06 ± 95.66 IU/mg using the sonication and freeze-thaw cycle methods, respectively. The effect of hCG loaded-exosomes on the endometrial receptivity was greater than the hCG or exosomes alone. We found that hCG upregulated LIF and Trophinin and downregulated Muc-16 and IGFBP1 genes. Interestingly, the effect of hCG on the expression of LIF and Muc-16 was significantly intensified when used in the form of hCG loaded-exosomes.

SIGNIFICANCE

These findings strengthen our hope in using uterine fluid-derived exosome as an effective carrier for proteins or other therapeutic agents to effective delivery into endometrial cells.

Human Chorionic Gonadotropin-Mediated Immune Responses That Facilitate Embryo Implantation and Placentation

Human chorionic gonadotropin (hCG) serves as one of the first signals provided by the embryo to the mother. Exactly at the time when the first step of the implantation process is initiated and the blastocyst adheres to the maternal endometrium, the embryonic tissue starts to actively secrete hCG. Shortly thereafter, the hormone can be detected in the maternal circulation where its concentration steadily increases throughout early pregnancy as it is continuously released by the forming placenta. Accumulating evidence underlines the critical function of hCG for embryo implantation and placentation. hCG not only regulates biological aspects of these early pregnancy events but also supports maternal immune cells in their function as helpers in the establishment of an adequate embryo-endometrial relationship. In view of its early presence in the maternal circulation, hCG has the potential to influence both local uterine immune cell populations as well as peripheral ones. The current review aims to summarize recent literature on the participation of innate and adaptive immune cells in embryo implantation and placentation with a specific focus on their regulation by hCG.