Galectins, a family of β-galactoside-binding proteins, are critical in regulating feto-maternal interactions during pregnancy. Their evolutionary trajectory is reflected in their expression patterns and diverse functions in embryo implantation, trophoblast invasion, and maternal immune and vascular adaptation, contributing to healthy placentation and uncomplicated pregnancy. Galectin-1 (gal-1), one of the most ancient galectins, plays a pivotal role in feto-maternal immune regulation, acting predominantly from the maternal side to promote immune tolerance, a function integrated early in placental mammalian evolution. In contrast, anthropoid primates introduced a unique set of fetal (placental) galectins (gal-13, gal-14, and gal-16) through birth-and-death evolution, with these genes localized on human chromosome 19. Notably, these primate species have evolved varying degrees of deep placentation, with humans exhibiting the deepest, which facilitates enhanced nutrient delivery to the fetus, particularly for brain development. Placental galectins have been implicated in the evolution of immune tolerance mechanisms that support deep placentation. During pregnancy, reduced expression of maternal galectins (e.g., gal-1) and placental galectins (e.g., gal-13) has been associated with severe obstetric complications, signaling disruptions in feto-maternal tolerance. This review provides a comprehensive overview of gal-1, gal-13, gal-14, and gal-16, highlighting their shared and unique roles in maternal and placental immune regulation and placental development. Additionally, the review explores the potential of maternal versus placental galectins as biomarkers and therapeutic targets to improve diagnostic and treatment strategies for adverse pregnancy outcomes.

IntroductionLight exposure of embryos during assisted reproduction affects embryo quality and implantation capacity in a wavelength dependent manner. We investigated the molecular mechanism of these light-induced changes through the comparative analysis of gene expression and regulatory miRNA profile of murine embryos cultured in dark environment and those exposed to white- or red filtered light. miRNA sequencing was used to assess the role of embryo-derived extracellular vesicles in the endometrium-embryo dialogue.MethodsIn vitro cultured mouse embryos at 3.5 days post coitum (dpc) were exposed to white or red filtered light. After 24 hours mRNA and miRNA content of the embryos as well as the miRNA content of embryo-derived extracellular vesicles were isolated and RNA-sequencing was performed. Differential expression analysis and functional enrichment analysis were used for evaluating the transcriptome results.ResultsLight exposure caused transcriptomic changes in the embryos. White light upregulated apoptotic pathways, while red filtered light gave rise to the activation of regeneration pathways, including DNA repair mechanisms. Embryo-derived extracellular vesicles enclosed wavelength dependently unique miRNA cargos the target genes of which play a role in embryo implantation.DiscussionWhite light upregulates apoptotic pathways, at both the transcriptome and regulatory miRNAs levels. Red filtration partially counterbalances these negative effects by shifting the cellular processes towards regeneration, including DNA repair mechanisms. Extracellular vesicles of light exposed embryos play a role in blastocyst-decidua communication through the horizontal transfer of regulatory miRNAs. Our data prove that light exposure during in vitro fertilization modifies cell function that might affect the outcome of implantation.

OBJECTIVE:Early embryonic development is characterized by rapid cell division and gene activation, making the embryo extremely sensitive to environmental influences. Light exposure can affect embryonic development through a direct toxic effect on the embryo via the generation of reactive oxygen species. In a previous study, we demonstrated the positive effect of improved light-protected embryo culture conditions implemented in our laboratory. This study aimed to investigate the changes in human embryo development under light protection during the conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).MATERIALS AND METHODS:We tested the potential beneficial effect of light filters to reduce the risk of toxic effects of light. IVF outcomes were compared between two experimental conditions, light protection with red light filters versus no light protection as a control.RESULTS:Blastocyst development rate in IVF was significantly higher in the light-protected group than in the group treated under conventional conditions (46.6 vs. 26.7%). In the case of ICSI, we obtained a similar result (44.5 vs. 31.6%). The rate of cryopreservation with at least one embryo was higher in the light-protected phase (32.8%) than in the conventionally manipulated phase (26.8%). The abortion rate was also significantly lower during the light-protected period in IVF, resulting in a higher live birth rate.CONCLUSIONS:The implementation of light protection to reduce the embryotoxic wavelengths of light in IVF centers may improve the blastocyst development rate and embryo quality while maintaining embryo safety.

Recurrent pregnancy loss (RPL) is a multifactorial disorder, associated with immunologic abnormalities. During pregnancy, the maternal immune system uses different tolerance mechanisms to deal with a semi-allogenic fetus. The expression of immune checkpoints and their related miRNAs in immune cells can ensure pregnancy at the feto-maternal interface by modulating immune responses. This study aims to evaluate the expression of the immune checkpoint molecules PD -1 and Tim -3 on circulating T cells by flow cytometry, that of mir-138 and mir155 in PBMCs by Real-time PCR, and the concentrations of TGF-beta and IP-10 in the sera of women suffering from RPL as well as of gestational age -matched healthy pregnant women by ELISA. The percentage of PD -1 or Tim -3 expressing CD8+ T cells was significantly lower in RPL patients compared to the controls, while there was no significant difference in Tim -3 expression of CD4+ T cells between the two groups. The mRNA of both the PD -1 and Tim -3 genes were downregulated in PBMCs of RPL patients compared to controls, however, the difference was not statistically significant for Tim -3. The concentration of TGF-beta was significantly lower and that of IP-10 was significantly higher in the sera of RPL patients than in those of the controls. The relative expression of mir138 and miR-155 were significantly lower, in PBMCs of RPL patients than in those of healthy pregnant women. These data confirm that by affecting cytokine production, immune checkpoints, and microRNAs play a role in establishing the appropriate local immune environment for successful pregnancy. The wider analysis of immune checkpoints may also yield new biomarkers for the diagnosis and prevention of RPL.

With the increased utilization of assisted reproductive technology (ART), concerns about the potential health risks for ART-conceived babies have also been raised. Increased prevalences of allergic and metabolic diseases have been reported among ART offspring. This study aimed to evaluate the impact of IVF on the tendency to develop allergic responses following ovalbumin (OVA) sensitization in IVF-conceived mice. Mice were divided into four groups (non-OVA naturally conceived, OVA naturally conceived, non-OVA IVF-conceived, and OVA IVF-conceived). In the OVA groups, the mice were subjected to intraperitoneal and intranasal immunization with OVA. Two days after the final immunization, blood samples were taken, and the serum levels of IgE and IL-4 were detected by ELISA. The mice were sacrificed by cervical dislocation, their spleens and lungs were removed, and their weights were measured and recorded. Sensitization with OVA resulted in significantly increased concentrations of IL-4 and total IgE, as well as increased lung and spleen weights, among offspring from both natural and IVF conception. The concentrations of IgE and IL-4 and the lung and spleen weights in IVF-conceived mice were significantly higher compared to those in naturally conceived mice before and after sensitization with OVA. It is concluded that compared to naturally conceived mice, IVF-conceived mice exhibit a greater tendency to develop allergic responses against OVA.

Department of Medical Biology, Medical School, Pecs University, National Laboratory on Reproduction, Szentágothai János Research Center, MTA - PTE Human Reproduction Research Group Pecs University, Pecs, Hungary A complex communication network of finely tuned mechanisms is required for the survival and well-being of the foetus in the potentially hostile maternal immune environment. Via its downstream mediator, PIBF progesterone acts as a conductor in the orchestra of cytokine production, the generation and activity of regulatory T cells, NK cells and other players of the immune response. The role that progesterone and, PIBF play in regulating this mechanism, as well as the clinical consequences of progesterone deficiency will be discussed.

Earlier data suggest that extracellular vesicles (EVs) released by cultured embryos alter the cytokine production of peripheral lymphocytes. To further study the interaction of embryo-derived EVs and the maternal immune system, we tested the expression of immune checkpoint ligands on light-stressed and control embryos (Light exposed - and control cultured mouse embryos serve as a model for poorly implanting and competent human embryos). Eight to 12 weeks, super-ovulated CD1 female mice were mated with CD1 males. Two days later two-cell stage embryos were flushed from the Fallopian tubes, and cultured, until they reached the morula stage, when the embryos were exposed to white light of 1130 Lux intensity, for 50 minutes. After 24 h culture following the treatment, the culture media were collected, and the EVs were labelled with antibodies specific for immune checkpoint ligands. All antibodies (to CD86, CD80, CD252(OX-40L), CD70, PD-L1(CD274)., PD-L2(CD273) and Galectin-9) were purchased from Sony Biotechnology Inc. (1730 North First Street, San Jose). The expression of the immune checkpoint ligands on EVs released by light-stressed and non-stressed embryos was determined by flow cytometric analysis, using and Apogee flow cytometer. The two-tailed Student t-test was used for statistical analysis. EVs from control embryos expressed all molecules at a higher level, than those, from light stressed embryos. However only CD86 and CD70 expression were significantly decreased on EVs from light stressed embryos. Immune checkpoint ligands moderate the immune response through binding to immune checkpoint receptors, which are negative regulators of immune responses and promote self-tolerance. CD86 is the ligand of the inhibitory receptor CTLA-4, which is constitutively expressed in regulatory T cells, while CD 70 is the ligand of the CD27 molecule expressed on T cells and NK cells. Probably due to the low sample size - the different expression of these molecules on EVs from light stressed and control embryos did not in all cases reach the level of statistical significance. Nevertheless, these data suggest that competent embryos might communicate with the maternal immune system in the peri-implantation period, while in stressed embryos the communication is disturbed, which eventually results in poor implantation.

The evidence concerning the role of vitamin D (VD) in reproduction is still inconclusive. Calcitriol was given to superovulated female mice at the time of FSH injection (Group A), or at day 0.5 of pregnancy (Group B). The retrieved and cultured embryos were transferred to the uteri of pseudopregnant females. Ten animals from each group conceived naturally, and at day 7.5 of pregnancy, the implantation sites were counted. Serum hormone concentrations were determined by ELISA. The expression of CD70, PD-L1, OX-40L, and PIBF on extracellular vesicles (EVs) was tested by flow cytometry. Calcitriol treatment did not alter serum oestradiol concentrations, while 25(OH) D levels significantly decreased in both treated groups. Progesterone concentrations were significantly higher in group A and lower in group B than in the controls. On EVs produced by group B embryos PIBF, CD70, and OX-40L expression were significantly lower, while that of PD-L1 was significantly higher than that of controls. Calcitriol treatment decreased the fertilization rate in group A, and the blastulation rate of cultured embryos in group B, while the implantation capacity of the embryos was not affected, suggesting that depending on the time of administration, VD has an adverse effect on oocyte maturation and embryo development, but not on the implantation rates.

The endometrial microbiota refers to the collection of microorganisms, mainly bacteria, that reside in the endometrial lining of the uterus. This microbiota is a relatively new area of research, and its composition is not yet fully understood. Disruptions in the endometrial microbiota have been associated with various reproductive disorders, including endometriosis, infertility, and pregnancy complications. Our study aimed to determine endometrial microbiota composition and its possible role in IVF success. Forty women with unexplained female infertility were included in the investigation. DNA was isolated from the rinse solution of the tips of embryo transfer catheters used during the IVF procedure. Possible cervical and vaginal contamination was avoided. Shotgun metagenomic sequencing was carried out to identify bacterial and viral members of endometrial microbiota. With the help of bioinformatic analysis, the presence of certain bacteria and viruses in the uterus could be demonstrated reliably.

In the human placenta, the syncytiotrophoblast forms the interface between fetus and mother. It permanently releases extracellular vesicles (EVs) such as exosomes and microvesicles into the maternal circulation. These EVs contain fetal proteins, DNA and RNA for communication with neighboring and distant maternal cells. The number, size and content of particles may reflect or predict placental disorders and can be assessed in maternal serum samples. EVs may be taken up by a variety of cells, including different types of immune cells. They can react upon the simple interaction with EVs, but also upon the release of specific EV-delivered factors. These interactions can be mimicked ex vivo or in vitro. By applying adapted centrifugation protocols, different subtypes of EVs can be isolated and enriched from blood, ex vivo placenta perfusates or cell line supernatants. Transfection of trophoblastic cell lines can be used to modify the content of their EVs, for example that of specific microRNAs. Coincubation of such EVs with potential target cells, such as immune cells, and potentially, cells in almost all organ systems, leads to increase of trophoblast-derived miRNAs in these cells where they may exert their functions. This messaging may contribute to the preparation and adaptation of the maternal immune system and the entire organism in healthy pregnancy and its pathologies.

The embryo that carries paternal antigens is at risk of being attacked by the maternal immune system. Immunological recognition of pregnancy initiates interactions between the conceptus and the mother, which results in a series of changes, and eventually in a tolerant immunological attitude toward the foetus. Immunomodulatory molecules and miRNAs carried by embryo-derived extracellular vesicles as well as the expression pattern of immune checkpoint ligands on the extracellular vesicles, modify the function of maternal immune cells. Embryo-maternal communication is orchestrated by the hormonal environment. During the implantation window, the receptive endometrium screens the embryos for quality, and only those with a good developmental potential will implant. Antigens expressed by the embryo/foetus activate the maternal immune system and induce progesterone receptors in the lymphocytes, enabling progesterone-dependent immunomodulation. Similarly to other steroid hormones, progesterone acts via mediators. Progesterone binding to its receptor in the lymphocytes induces gene activation and the synthesis of PIBF, - a protein with immunomodulatory properties. Via PIBF progesterone controls the fine tuning of cytokine production, and affects the generation and function of regulatory T cells, NK cells and other players of the immune response. In the absence of progesterone-dependent immunomodulation, implantation rates in mice are poor, and pregnancies that are established nevertheless, end up in resorptions due to a Th1 dominant cytokine production, and high decidual NK activity. In conclusion; a complex communication network of finely tuned mechanisms is required for establishing a milieu that enables the foetus to survive in a potentially hostile immunological environment.

Assisted reproductive technologies (ART) significantly increase the chance of successful pregnancy and live birth in infertile couples. The different procedures for ART, including in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), intrauterine insemination (IUI), and gamete intrafallopian tube transfer (GIFT), are widely used to overcome infertility-related problems. In spite of its inarguable usefulness, concerns about the health consequences of ART-conceived babies have been raised. There are reports about the association of ART with birth defects and health complications, e.g., malignancies, high blood pressure, generalized vascular functional disorders, asthma and metabolic disorders in later life. It has been suggested that hormonal treatment of the mother, and the artificial environment during the manipulation of gametes and embryos may cause genomic and epigenetic alterations and subsequent complications in the health status of ART-conceived babies. In the current study, we aimed to review the possible long-term consequences of different ART procedures on the subsequent health status of ART-conceived offspring, considering the confounding factors that might account for/contribute to the long-term consequences.

Vitamin D has a well-established role in calcium homeostasis, but little is known about its effects on the immune system and reproduction. We examined the effects of vitamin D treatment on oocyte and embryo development and evaluated the expression of immune checkpoint ligands on extracellular vesicles produced by embryos from control and vitamin D exposed mice. Eight weeks old CD1 females were injected with 100 ng of Calcitriol at different phases of the superovulation treatment. Group A; Mice were treated with Calcitriol at the time of the FSH injection. Two days later, mice were treated with HCG and mated (some mice were sacrificed 2.5 days after Calcitriol treatment, for blood collection). On day 1.5 of pregnancy, embryos were isolated and cultured. Animals in Group B were HCG treated two days after the FSH injection, and placed with males. The next day plugged mice (on day 0.5 of pregnancy) received a Calcitriol injection. On day 1.5 of pregnancy the mice were sacrificed, blood was collected, embryos were isolated and cultured. Mice in the control group underwent the same protocol, without Calcitriol injection. Serum progesterone, estradiol and total 25-hydroxyvitamin D levels were measured by competitive chemiluminescent immunoassays. The number of oocytes and embryo development were checked by light microscopy. Immune checkpoint ligands and PIBF on the surface embryo-derived extracellular vesicles were determined by flow cytometry. Compared to the controls, serum progesterone levels were significantly higher in mice that received the Calcitriol at the time of the FSH injection, while those treated with Calcitriol on day 0.5 of pregnancy had significantly lower progesterone levels than the controls. Serum estradiol concentrations were not affected in either groups. Probably due to negative feedback, 25(OH)D serum concentrations were significantly lower in both groups, compared to the controls. Group A mice produced a lower number of embryos, and the % of unfertilized oocytes was significantly higher than in the controls. In Group B animals, these parameters did not significantly differ from the controls. On the other hand, the percentage of embryos that developed to blastocysts during in vitro culture, was significantly lower in both Calcitriol- treated groups than in the controls, though only in Group B were the differences statistically significant. On EVs produced by the embryos from mice treated with Calcitriol on day 0.5 of pregnancy, the expression of most immune checkpoint ligands as well as of PIBF was lower than on EVs from control embryos. The effect of vitamin D on embryo development is not necessarily beneficial, and depends on the time of administration. If Calcitriol is given before proestrus, it affects oocyte development and the fertilization rate, whereas treatment at day 0.5 of pregnancy has a negative effect on embryo development. The decreased expression of immune checkpoint ligands on EVs produced by embryos from vitamin D – treated mice might render the embryos vulnerable to the maternal immune response.

During normal pregnancy, blood volume increases by nearly two liters. Distinctively, the absence and also the extreme extent regarding the volume expansion are likely accompanied with serious conditions. Undoubtedly, preeclampsia, defined as the appearance of hypertension and proteinuria during the second half of pregnancy, is not a homogenous disease. The early onset which begins prior to the 34th week, is characteristically a hypovolemia-associated form and depicts the placental origination, in which endothelial damage leads to hypertension and organ damage due to vasoconstriction and microthrombosis. Fetal blood supply progressively worsens due to placental insufficiency. The outcome of this condition often leads to fetal death, eclampsia, or placental abruption. Management is confined to a diligent prolongation of pregnancy to accomplish improved neonatal pulmonary function. The late onset form, associated with high cardiac output, is a maternal disease, in which obesity is a risk factor since it predisposes individuals to enhanced water retention, hypertension, and a weakened endothelial dysfunction. Initially, low extremity edema often times progresses to a generalized form and frequently results in hypertension. In several cases proteinuria appears. This condition entirely meets the preedampsia criteria. Fetal weight is normal or frequently over the average. It is very likely, the increasing parenchymal stasis will lead to ascites, eclampsia, or placental abruption. During the management of this hypervolemia-associated preedampsia, the administration of diuretic furosemide treatment seemingly offers promise.

Összefoglaló. Egészséges terhességben mintegy két literrel nő a vér mennyisége. A vérvolumen növekedésének elmaradása, de extrém mértékű növekedése is súlyos következményekkel szövődhet. Ma már nem kétséges, hogy a praeeclampsia, mely a várandósság második felében magas vérnyomás és proteinuria együttes megjelenése, nem egységes kórkép. A korai kezdetű (34. hét előtt jelentkező), hypovolaemiával járó praeeclampsia placentaris eredetű, melyben az endothelium sérülése vezet a magas vérnyomásért és szervkárosodásokért felelős vasoconstrictióhoz és microthrombosisok megjelenéséhez. Magzati sorvadás, oligohydramnion alakul ki a lepényi elégtelenség miatt. A kórkép végső stádiumában magzati elhalás, eclampsia, lepényleválás várható. Az állapot kezelésében rendkívül korlátozottak a lehetőségek; a cél, körültekintő monitorizálás és az állapot stabilizálása mellett, várakozás a magzati tüdő érettségének fokozódása érdekében. A késői kezdetű, nagy perctérfogattal járó praeeclampsia anyai betegség: ebben az obesitasnak kockázati szerepe van, mivel önmagában is hajlamosít fokozott folyadék-visszatartásra, magas vérnyomásra és mérsékelt endothelkárosodásra. A kezdeti lábszár-, majd generalizálódó oedema mellett nemritkán jelentkezik magas vérnyomás és az esetek egy részében proteinuria is, mely ekkor már megfelel a praeeclampsia kritériumának. A magzat súlya normális vagy átlag feletti. Az extrém fokú folyadékretenció, valószínűleg a parenchymalis pangás miatt, asciteshez, eclampsiához, lepényleváláshoz vezethet. A hypervolaemiával járó praeeclampsia kezelésében a diuretikus furoszemidkezelés ígéretesnek tűnik. Orv Hetil. 2022; 163(17): 663–669. Summary. During normal pregnancy, blood volume increases by nearly two liters. Distinctively, the absence and also the extreme extent regarding the volume expansion are likely accompanied with serious conditions. Undoubtedly, preeclampsia, defined as the appearance of hypertension and proteinuria during the second half of pregnancy, is not a homogenous disease. The early onset which begins prior to the 34th week, is characteristically a hypovolemia-associated form and depicts the placental origination, in which endothelial damage leads to hypertension and organ damage due to vasoconstriction and microthrombosis. Fetal blood supply progressively worsens due to placental insufficiency. The outcome of this condition often leads to fetal death, eclampsia, or placental abruption. Management is confined to a diligent prolongation of pregnancy to accomplish improved neonatal pulmonary function. The late onset form, associated with high cardiac output, is a maternal disease, in which obesity is a risk factor since it predisposes individuals to enhanced water retention, hypertension, and a weakened endothelial dysfunction. Initially, low extremity edema oftentimes progresses to a generalized form and frequently results in hypertension. In several cases proteinuria appears. This condition entirely meets the preeclampsia criteria. Fetal weight is normal or frequently over the average. It is very likely, the increasing parenchymal stasis will lead to ascites, eclampsia, or placental abruption. During the management of this hypervolemia-associated preeclampsia, the administration of diuretic furosemide treatment seemingly offers promise. Orv Hetil. 2022; 163(17): 663–669.

Paternal antigens expressed by the foetus are recognized as foreign. Therefore,-according to the rules of transplantation immunity-the foetus ought to be "rejected". However, during normal gestation, maternal immune functions are re-adjusted, in order to create a favourable environment for the developing foetus. Some of the mechanisms that contribute to the altered immunological environment, for example, the cytokine balance and NK cell function, with special emphasis on the role of progesterone and the progesterone-induced blocking factor (PIBF) will be reviewed.

This opinion paper briefly presents arguments that support the unlikelihood of an impact on female fertility from current covid-19 vaccines.