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Anna Lange-Consiglio, Emanuele Capra, Noemi Monferrini, Simone Canesi, Giampaolo Bosi, Marina Cretich, Roberto Frigerio, Valentina Galbiati, Federica Bertuzzo, Francesco Cobalchini, Fausto Cremonesi, and Bianca Gasparrini

Seminal plasma contains extracellular vesicles (EVs) that vehicle RNA, proteins, and other molecules able to influence the biological function of sperm. The aim of this study was to improve the fertilizing capacity of male gametes of low-fertility bulls using EVs isolated by ultracentrifugation from the seminal plasma of a bull of proven fertility. After dose-response curve, 10×106 sperm of low-fertility bulls were co-incubated for an hour with 400×106 EVs/ml. In addition, it has been verified that the incorporation of EVs, which takes place in the sperm midpiece, is maintained for 5 hours and even after cryopreservation. Subsequently, the spermatozoa of low-fertility bulls, with EVs incorporated, were used for the in vitro production of embryos. The rate of blastocyst at seventh day yield in vitro, with the use of sperm with EVs incorporated, increased by about twice the yield obtained with the same sperm in the absence of EVs: bulls having an average embryonic yield of 6.41±1.48%, 10.32±4.34% and 10.92±0.95% improved their yield to 21.21±1.99%, 22.17±6.09% and 19.99±5.78%, respectively (P<0.05). These encouraging results suggest that it might be possible to keep breeding bulls with poor fertility. Further studies will be needed to evaluate the in vivo fertility of sperm treated with EVs and understand how the content of EVs is involve in the sperm-vesicle interaction and in the improved sperm performance.

Jessica Roach, Juan Carlos Arango Sabogal, Ken Smith, Alastair Foote, Kristien Verheyen, and Amanda M de Mestre

Risk factors associated with equine reproductive efficiency have been identified along with those associated specifically with early pregnancy loss (EPL). In contrast, no studies have reported risk factors associated with abortion (loss between day 70 and 300 post-cover). Given the causes of abortion differ to those of EPL, likely too will the risk factors. A retrospective cohort study was carried out to identify risk factors associated with abortion in UK and Irish based Thoroughbreds, collecting data on 20 exposure variables over a five-year period. A generalized linear mixed model was utilized to evaluate the associations between exposure variables and abortion, with clustering of observations accounted for at the mare and farm level. Variables with a likelihood ratio test (LRT) p value <0.2 were entered into the model in a forward stepwise approach. Pregnancy outcome was available on 4,439 pregnancies from 2,510 mares. Having had two or more prior abortions (odds ratio (OR) 7.91, 95% confidence interval (CI) 2.86, 21.88), conceiving on the second or subsequent covered estrous cycle (OR 1.84, 95% CI 1.22, 2.78) and conceiving multiple conceptuses (OR 1.68, 95% CI 1.02, 2.76) were associated with an increased risk of abortion compared to null parous, first estrous cycle covers and singleton conceptions respectively. Increasing paternal age (OR 0.95, 95% CI 0.90, 0.99) was associated with a decreasing risk of abortion. Mare and farm variance were not significant in the final model, LRT p=0.43. These findings provide evidence-based data to inform Thoroughbred breeding management practices to help mitigate abortion risk.

Talita De Oliveira Farias, André Felipe Almeida Figueiredo, Natália Teixeira Wnuk, Sonia Aparecida Talamoni, and Guilherme Mattos Jardim Costa

Yellowish myotis present a seasonal reproduction, influenced by rainfall distribution, in which the testis mass, germ cell composition, and brown adipose tissue mass change along the reproductive stages. In the present study, tissue xenografts were performed in immunodeficient mice to investigate spermatogenesis development in a stable endocrine milieu and the possible androgenic role of brown adipose tissue. Forty-one adult male bats were captured in the Santuário do Caraça, Minas Gerais, Brazil. The gonads and brown adipose tissue were collected, weighed, and grafted under the mice's back skin. Mice biometric and hormonal data were evaluated after grafting, and the testis grafts and mice gonads were fixed for histological and immunohistochemical analyses. As a result, testis grafts from adult bats presented a continuous germ cell development in all reproductive phases, showing round spermatids in all testis tissues. Furthermore, testis fragments in the Rest stage presented elongating spermatids as the most advanced germ cell type in the seminiferous epithelium after seven months of grafting. These data indicated that yellowish myotis spermatogenesis could be continued (presenting a constant spermatogonial differentiation) in a stable endocrine milieu, as found in mice. In addition, the best spermatogenic development was achieved when testis fragments were transplanted at their lowest activity (Rest stage). Regarding the brown adipose tissue grafts, the adipose tissue consumption by mice increased seminal vesicle mass and testosterone serum levels. This data proved that the brown adipose tissue is related to testosterone synthesis, which may be critical in stimulating the differentiation of spermatogonia in yellowish myotis.

E Scott Sills and Samuel H. Wood

Ovarian platelet-rich plasma (PRP) is claimed to restore fertility potential by improving reserve, an effect perhaps mediated epigenetically by platelet-discharged regulatory elements rather than gonadotropin activated G-protein coupled receptors, as with stimulated in vitro fertilization (IVF). The finding that fresh activated platelet releaseate includes factors able to promote developmental signaling networks necessary to enable cell pluripotency tends to support this theory. The mechanistic uncertainty of intraovarian PRP notwithstanding, at least two other major challenges confront this controversial intervention. First is to clarify how perimenopausal ovarian function is reset to levels consistent with ovulation. Perhaps a less obvious secondary problem is to confine this renewal such that any induced recalibration of cellular plasticity is kept within acceptable physiologic bounds. Thus, any ‘drive’ to ovarian rejuvenation must incorporate both accelerator and brake. Ovarian aging may be best viewed as a safeguard against pathologic overgrowth, where senescence operates as an evolved tumor-suppression response. While most ovary cells reach the close of their metabolic lifespan with low risk for hypertrophy, enhanced lysosomal activity and the pro-inflammatory ‘Senescence Associated Secretory Phenotype’ usually offsets this advantage over time. But is recovery of ovarian fitness possible, even if only briefly prior to IVF? Alterations in gap junctions, bio-conductive features, and modulation of gene regulatory networks after PRP use in other tissues are discussed here alongside early data reported from reproductive medicine.

Menghe Liu, Katja Hummitzsch, Nicole A Bastian, Monica D Hartanti, Helen F Irving-Rodgers, Richard A Anderson, and Raymond J Rodgers

Polycystic ovary syndrome (PCOS) is an endocrine metabolic disorder that appears to have a genetic predisposition and a fetal origin. The fetal ovary has two major somatic cell types shown previously to be of different cellular origins and different morphologies and to differentially express 15 genes. In this study, we isolated the somatic gonadal ridge epithelial-like (GREL) cells (n  = 7) and ovarian fetal fibroblasts (n  = 6) by clonal expansion. Using qRT-PCR, we compared the gene expression levels of PCOS candidate genes with previous data on the expression levels in whole fetal ovaries across gestation. We also compared these levels with those in bovine adult ovarian cells including fibroblasts (n  = 4), granulosa cells (n  = 5) and surface epithelial cells (n  = 5). Adult cell types exhibited clear differences in the expression of most genes. In fetal ovarian cells, DENND1A and ERBB3 had significantly higher expression in GREL cells. HMGA2 and TGFB1I1 tended to have higher expression in fetal fibroblasts than GREL cells. The other 19 genes did not exhibit differences between GREL cells and fetal fibroblasts and FBN3, FSHB, LHCGR, FSHR and ZBTB16 were very lowly expressed in GREL cells and fibroblasts. The culture of fetal fibroblasts in EGF-containing medium resulted in lower expression of NEIL2 but higher expression of MAPRE1 compared to culture in the absence of EGF. Thus, the two fetal ovarian somatic cell types mostly lacked differential expression of PCOS candidate genes.

Lay summary

Polycystic ovary syndrome (PCOS) is one of the most common reproductive problems. The cause is not known so there are no specific treatments or prevention strategies. We know it can be linked to issues that occur in the womb and that some people may be more likely to get PCOS due to their genetic makeup. Our recent studies showed that many of the genes linked to PCOS were found to be switched on in the fetal ovary and are likely to be involved in the development of the fetal ovary. In order to improve our understanding of PCOS, we need to identify the type of cells in the fetal ovary where these genes are switched on. In this study, we examined the PCOS genes in two types of cells that mature as the fetal ovary develops and found very little difference between them but bigger differences to their mature adult counterparts.

Kevin Marron and Conor Harrity

The purpose of this study was to determine if a comprehensive flow cytometry panel could be used to assess immunophenotype profiles in menstrual blood of patients experiencing reproductive failure and age-matched controls of proven fertility. Menstrual blood samples of 58 recurrent pregnancy loss and repeated implantation failure patients, along with 15 age-matched controls of proven fertility, were obtained within the first 24 h of the onset of menstruation to non-invasively assess the local immunophenotype. Using a comprehensive multi-parameter flow panel, the lymphocyte sub-populations were described and compared. In relation to well-established peripheral blood immunophenotyping values, distinct lymphocyte population differences were noted between the subgroups. The ratios of CD4+ and CD8+ T-cells were inverted in relation to peripheral blood, and uterine natural killler (NK) cells represented by CD56bright were distinctly visualised, emphasising the distinction between menstrual and peripheral blood. In relation to controls, there were marked increases in CD3+ve T-cells (P = 0.009), CD4:CD8 ratio (P = 0.004), CD19 B-cells (P = 0.026) and CD56dim NK cells (P = 0.002) in the reproductive failure cases. The study shows that flow cytometric evaluation could provide a rapid and objective analysis of lymphocyte subpopulations in many forms of tissue and fluid. The findings show significant variations in cellular composition of immune cells indicating a distinct compartment, with differences between cases and controls. Immunological assessment of the menstrual blood immunophenotype, in clinically appropriate patients, may provide insight into the aetiology of adverse reproductive outcome, without the risks and inconveniences associated with a more invasive endometrial biopsy.

Lay summary

Unexplained infertility is a difficult issue for patients and physicians, but despite diagnostic strides and innovative methods, there are no clear solutions. The involvement of an overactive or underactive immune system in selected cases is undeniable, and the endometrial lining is the most relevant area for investigation because this is where the embryo implants. Endometrial investigations, however, are highly invasive, involve medication and have to be done at the right time. The method described and evaluated here is an alternative assessment which avoids these difficulties and can be used in a clinical setting.

Lysia Demetriou, Christian M Becker, Beatriz Martínez-Burgo, Adriana L Invitti, Marina Kvaskoff, Razneen Shah, Emma Evans, Claire E Lunde, Emma Cox, Kurtis Garbutt, Krina T Zondervan, Elaine Fox, and Katy Vincent

Endometriosis is a chronic condition that affects ~10% of women globally. Its symptoms include chronic pelvic pain, heavy periods and tiredness/fatigue, which have been associated with poorer quality of life and mental health. We aim to explore the impact of the COVID-19 pandemic on pain and fatigue symptoms and their interactions with the impact on mental health in people with endometriosis. This global cross-sectional online survey study collected data from 4717 adults with self-reported surgical/radiological diagnosis of endometriosis between May and June 2020. The survey included questions on the current status and changes of endometriosis symptoms (pelvic pain, tiredness/fatigue, and bleeding patterns), mental health, pain catastrophising, and the impact of the COVID-19 pandemic on the respondents’ lives. Compared to 6 months earlier, Respondents reported a marked worsening of their endometriosis symptoms (endometriosis-associated pain (39.3%; 95% CI: 37.7, 40.5), tiredness/fatigue (49.9%; 95% CI: 48.4, 51.2) and bleeding patterns (39.6%; 95% CI: 38.2, 41)) and mental health (38.6%; 95% CI: 37.2, 39.9). Those with a pre-existing mental health diagnosis (38.8%) were more likely to report their symptoms worsening. Worsening of pain and tiredness/fatigue was significantly correlated with worsening of mental health (P < 0.001). The relationship between changes in mental health and (a) change in pain and (b) change in fatigue was found to be weakly mediated by pain catastrophising scores (pain: B = 0.071, lower limit of confidence interval (LLCI) = 0.060, upper limit of confidence interval (ULCI) = 0.082, tiredness/fatigue: B = 0.050, LLCI = 0.040, ULCI = 0.060). This study demonstrates that stressful experiences impact the physical and mental health of people with endometriosis. The findings highlight the need to consider psychological approaches in the holistic management of people with endometriosis.

Lay summary

Endometriosis is a chronic condition in which tissue similar to that of the lining of the womb grows outside it. It affects around 10% of women globally, and the symptoms often include persistent pelvic pain, heavy periods and tiredness/fatigue. These symptoms are associated with impaired mental health and life quality. This study used an online questionnaire to assess the experiences of people with endometriosis during the first months of the pandemic. Results from 4717 adults revealed that pelvic pain, tiredness/fatigue and bleeding worsened in more than 39% of the participants. Poor mental health was also exacerbated and associated with worsening in tiredness/fatigue. Further analysis revealed that this relationship could be partially explained by ‘pain catastrophising’, which measures how participants think about their pain. Our results suggest that stressful experiences like the pandemic negatively impact the already burdened mental health of people with endometriosis, who could benefit from psychological interventions.

Fabiana B Kohlrausch, Fang Wang, Danxia Luo, Rebecca Mahn, and David L Keefe

Lay summary

The placenta plays an essential role at the beginning of life, nourishing and supporting the fetus, but its life span is limited. In late pregnancy, the placenta develops signs of aging, including inflammation and impaired function, which may complicate pregnancy. Placentas also show another sign of aging – cells with extra or missing chromosomes. Chromosomally abnormal cells could gather in the placenta if they get stranded there and/or if the cells do not separate normally. Chromosome separation goes wrong in aging cells when the DNA sequences, which protect the ends of the chromosomes, erode. When chromosomes lose their protective caps, they fuse which leads to abnormal numbers of chromosomes. In this pilot study, for the first time, we found fusions between the caps in a human placenta when it reaches full term. More studies are needed to decide whether this has an influence on how the placenta works and outcomes of pregnancy.

Jennifer E Pearson-Farr, Gabrielle Wheway, Maaike S A Jongen, Patricia Goggin, Rohan M Lewis, Ying Cheong, and Jane K Cleal

Endometrial glands are essential for fertility, consisting of ciliated and secretory cells that facilitate a suitable uterine environment for embryo implantation. This study sought to determine whether an endometrial gland-specific transcriptome and splicing profile are altered in women with recurrent pregnancy loss. Our data provide a comprehensive catalogue of cilia and progestagen-associated endometrial protein (PAEP) gene isoforms and relative exon usage in endometrial glands. We report a previously unannotated endometrial gland cilia transcript GALNT11 and its susceptibility to exon skipping. Key endometrial receptivity gene transcripts are also reported to change in endometrial glands of women with recurrent pregnancy loss. The endometrial gland cilia and PAEP targets identified in this study could be used to identify a perturbed endometrium, isolate causes of recurrent pregnancy loss and develop targeted therapies in personalised medicine.

Lay summary

Successful embryo implantation is a trade-off between the lining of the womb which receives an implanting embryo, termed the endometrium, and a good quality embryo. For days 21–24 of the menstrual cycle, the endometrium undergoes changes into a receptive state in which it can receive an implanting embryo. Inappropriate endometrial receptivity is thought to underlie recurrent pregnancy loss. Improving pregnancy success in women with recurrent pregnancy loss requires an increased understanding of the endometrium at the molecular level. Genes contain the instructions for the cell and which genes are turned on or off determine how well it can do its role. We sought to determine a gene expression pattern of human endometrial glands in women with recurrent pregnancy loss (n = 5) vs a control group (n = 5). We identify target genes altered in women with recurrent pregnancy loss. Endometrial gland markers could be used to identify inappropriate endometrial receptivity.

Madara S B Ralapanawe, Sugandika Lakmali Gajaweera, Nishendra Karunaratne, Malcolm James Price, Pedro Melo, Arri Coomarasamy, and Ioannis Gallos

The use of intracytoplasmic sperm injection (ICSI) has recently increased worldwide. The live birth rate per ICSI cycle is low, and over half of infertile couples remain childless. Chromosomal polymorphisms are up to five times more common in couples with infertility compared to the general population. We aimed to investigate the association between chromosomal polymorphisms and reproductive outcomes in couples undergoing ICSI treatment. We analysed 942 ICSI fresh and frozen embryo transfer cycles in 697 women who underwent karyotyping analysis using Giemsa-Trypsin-Leishman banding prior to assisted conception at the Fertility Centre of Lanka Hospitals, Sri Lanka, between 2016 and 2018. The primary outcomes were pregnancy, miscarriage, and live birth rates. We compared outcomes according to the presence or absence of chromosomal polymorphism in females, males and couples. There were 294 pregnancies (31.2%) recorded in the study; 130 suffered a miscarriage (13.8%), 13 were ectopic pregnancies (1.3%) and 151 resulted in a live birth (16.0%). The evidence from univariable and multivariable analyses (adjusted for age, BMI, ovarian reserve and treatment type) did not confidently identify a difference in pregnancy, miscarriage or live birth rates between couples with no chromosomal polymorphisms compared to couples where the female, male or both partners were carriers of a chromosomal polymorphism. Further, we did not identify a clear association between the presence of chromosomal polymorphisms and reproductive outcomes compared to participants without chromosomal polymorphisms. Wide CIs precluded the identification of clinically meaningful associations.

Lay summary

Infertility affects approximately one in eight couples worldwide. The use of intracytoplasmic sperm injection (ICSI), where the sperm is directly injected into an egg using a micromanipulator outside the body, has become particularly popular in recent years. However, the success rate remains low. In human cells, the genetic material is arranged in structures called chromosomes. Chromosomal polymorphism is a normal variation where the genetic material is arranged differently to the average individual and is more common in infertile couples compared to the general population. We analysed data from 942 ICSI cycles in 697 couples who underwent karyotyping analysis to assess the changes in chromosomes between 2016 and 2018. The pregnancy rate was 31.2%, with 16.0% of participants experiencing a live birth, while 13.8% of pregnancies resulted in a miscarriage and 1.3% were outside the womb cavity (ectopic). The evidence did not identify a clear association between the chromosomal polymorphism and the outcome of treatment.