Anti-Müllerian hormone beyond an ovarian reserve marker: the relationship with the physiology and pathology in the life-long follicle development

Anti-Müllerian hormone (AMH), an indirect indicator of the number of remaining follicles, is clinically used as a test for ovarian reserve. Typically, a decline suggests a decrease in the number of remaining follicles in relation to ovarian toxicity caused by interventions, which may implicate fertility. In contrast, serum AMH levels are elevated in patients with polycystic ovary syndrome. AMH is produced primarily in the granulosa cells of the preantral and small antral follicles. Thus it varies in association with folliculogenesis and the establishment and shrinking of the follicle cohort. Ovarian activity during the female half-life, from the embryonic period to menopause, is based on folliculogenesis and maintenance of the follicle cohort, which is influenced by developmental processes, life events, and interventions. AMH trends over a woman's lifetime are associated with in vivo follicular cohort transitions that cannot be observed directly.

Na+/H+ Exchangers (NHEs) in Mammalian Sperm: Essential Contributors to Male Fertility

Na+/H+ exchangers (NHEs) are known to be important regulators of pH in multiple intracellular compartments of eukaryotic cells. Sperm function is especially dependent on changes in pH and thus it has been postulated that NHEs play important roles in regulating the intracellular pH of these cells. For example, in order to achieve fertilization, mature sperm must maintain a basal pH in the male reproductive tract and then alkalize in response to specific signals in the female reproductive tract during the capacitation process. Eight NHE isoforms are expressed in mammalian testis/sperm: NHE1, NHE3, NHE5, NHE8, NHA1, NHA2, NHE10, and NHE11. These NHE isoforms are expressed at varying times during spermatogenesis and localize to different subcellular structures in developing and mature sperm where they contribute to multiple aspects of sperm physiology and male fertility including proper sperm development/morphogenesis, motility, capacitation, and the acrosome reaction. Previous work has provided evidence for NHE3, NHE8, NHA1, NHA2, and NHE10 being critical for male fertility in mice and NHE10 has recently been shown to be essential for male fertility in humans. In this article we review what is known about each NHE isoform expressed in mammalian sperm and discuss the physiological significance of each NHE isoform with respect to male fertility.

Chemotherapy-induced ovarian damage and protective strategies

More than 9.2 million women worldwide suffer from cancer, and about 5% of them are at reproductive age. Chemotherapy-induced impairment of fertility affects the quality of life of these women. Several chemotherapeutic agents have been proven to cause apoptosis and autophagy by inducing DNA damage and cellular stress. Injuries to the ovarian stroma and micro-vessel network are also considered as pivotal factors resulting in ovarian dysfunction induced by chemotherapeutic agents. Primordial follicle pool over-activation may also be the mechanism inducing damage to the ovarian reserve. Although many studies have explored the mechanisms involved in chemotherapy-induced reproductive toxicity, the exact molecular mechanisms have not been elucidated. It is essential to understand the mechanisms involved in ovarian damage, in order to develop potential protective treatments to preserve fertility. In this article, we reviewed the current knowledge on the mechanism of chemotherapy-induced ovarian damage and possible protective strategies that prevent the ovary from such damages.

Outcome of uterine functional structures protection by fertility preservative PUSH surgery in diffuse adenomyosis

This study reports the outcomes of an innovative fertility-preserving surgery for the treatment of diffuse adenomyosis that is known as a surgery for protection of uterine structure for healing (PUSH Surgery). Developed at Peking University Shenzhen Hospital, PUSH Surgery aims to achieve radical excision of adenomyotic lesions by reconstructing the uterus with overlapping muscle flaps to promote optimal healing of the uterine wall and reduce the risk of scar rupture in subsequent pregnancies. PUSH Surgery was performed on 146 patients with diffuse adenomyosis, with uteri measuring from 8 to 16 gestational weeks and an average volume of 230 ± 150cm³. Regular follow-up was conducted for up to 156 months, revealing a significant reduction in VAS pain scores from 9.4 ± 1.2 before the surgery to 0.3 ± 0.8 and 0.6 ± 1.0 at 1 and 2 years post-surgery, respectively, with a continuous alleviation rate of 96.4% after the operations. Notably, 100% of patients with severe menorrhagia reported normal menstruation volumes within 2 years. Additionally, 31 patients attempted to conceive, resulting in a 58% postoperative pregnancy rate and a 60.0% intrauterine live embryo rate. Operation-related complications occurred in 2.7% of patients, with a 3.6% recurrence rate after more than 2 years of follow-up. Importantly, no cases of uterine rupture or severe complications were observed in the pregnant patients. In conclusion, PUSH Surgery offers a promising approach for the radical excision of adenomyotic lesions, promoting improved tissue healing and significant symptom relief.

Facilitation of Ovarian Response by Mechanical Force-Latest Insight on Fertility Improvement in Women with Poor Ovarian Response or Primary Ovarian Insufficiency

The decline in fertility in aging women, especially those with poor ovarian response (POR) or primary ovarian insufficiency (POI), is a major concern for modern IVF centers. Fertility treatments have traditionally relied on gonadotropin- and steroid-hormone-based IVF practices, but these methods have limitations, especially for women with aging ovaries. Researchers have been motivated to explore alternative approaches. Ovarian aging is a complicated process, and the deterioration of oocytes, follicular cells, the extracellular matrix (ECM), and the stromal compartment can all contribute to declining fertility. Adjunct interventions that involve the use of hormones, steroids, and cofactors and gamete engineering are two major research areas aimed to improve fertility in aging women. Additionally, mechanical procedures including the In Vitro Activation (IVA) procedure, which combines pharmacological activators and fragmentation of ovarian strips, and the Whole Ovary Laparoscopic Incision (WOLI) procedure that solely relies on mechanical manipulation in vivo have shown promising results in improving follicle growth and fertility in women with POR and POI. Advances in the use of mechanical procedures have brought exciting opportunities to improve fertility outcomes in aging women with POR or POI. While the lack of a comprehensive understanding of the molecular mechanisms that lead to fertility decline in aging women remains a major challenge for further improvement of mechanical-manipulation-based approaches, recent progress has provided a better view of how these procedures promote folliculogenesis in the fibrotic and avascular aging ovaries. In this review, we first provide a brief overview of the potential mechanisms that contribute to ovarian aging in POI and POR patients, followed by a discussion of measures that aim to improve ovarian folliculogenesis in aging women. At last, we discuss the likely mechanisms that contribute to the outcomes of IVA and WOLI procedures and potential future directions.

Impact of paternal age on assisted reproductive technology outcomes and offspring health: a systematic review

BACKGROUND

The increase in paternal age and the percentage of births after assisted reproductive technologies (ART) may have consequences on offspring and society's position regarding access to ART must be questioned. Most countries recommend limiting ART to men under 60 years. What is the rationale for this threshold?

OBJECTIVE

This systematic review assesses scientific arguments to establish links between paternal age, male fertility, and offspring health.

MATERIAL AND METHODS

Using the PRISMA guidelines, this systematic review of the literature analyzed 111 articles selected after screening PubMed, ScienceDirect, and Web of Science for articles published between January 1, 1995 and December 31, 2021.

RESULTS

A strong correlation was highlighted between advanced paternal age and a decrease of some sperm parameters (semen volume and sperm motility) and infant morbidity (exponentially increased incidence of achondroplasia and Apert syndrome, and more moderately increased incidence of autism and schizophrenia). The impact of paternal age on pregnancy and fetal aneuploidy rates is more controversial. No association was found with spontaneous abortion rates.

DISCUSSION AND CONCLUSION

The scientific parameters should be explained to older parents undergoing ART. And for countries that discuss a limit on paternal age for access to ART, the debate requires consideration of social and ethical arguments.

Boar fertility is controlled through systematic changes of mitochondrial protein expression during sperm capacitation

Vigorous activation of mitochondria in spermatozoa during capacitation induces the biological and morphological changes of spermatozoa to acquire fertilizing ability. To in-depth understand the dynamic roles of mitochondrial and male fertility, this study was to identify how the mitochondrial proteins are changed during sperm capacitation and regulate male fertility using boar spermatozoa. The mitochondrial proteins were differentially changed during sperm capacitation according to fertility status, i.e., superior litter size (SL) and normal litter size (NL). Following sperm capacitation, ubiquitin-cytochrome c reductase core protein (UQCRC1) and ATP synthase F1 (ATP5F1) increased in NL, while cytochrome c oxidase subunit 5B (COX5B), and cytochrome c1 (CYC1) proteins decreased. In contrast, only and ubiquinone oxidoreductase core subunit 8 (NDUFS8) protein was increased in SL following capacitation. The protein expression difference value of CYC1, COX5B, and NDUFS8 following sperm capacitation was lower in NL than SL boars. Based on these complicated changes during sperm capacitation, the accuracy for predicting male fertility of NDUFS8 was increased to 87 %. Overall, considering the systematic orchestration of mitochondrial protein expression according to sperm capacitation status, it will be possible to better understand male fertility.

Effect of reproductive management programs that prioritized artificial insemination at detected estrus or timed artificial insemination on the reproductive performance of primiparous Holstein cows of different genetic merit for fertility

Our objective was to compare reproductive outcomes of primiparous lactating Holstein cows of different genetic merit for fertility submitted for insemination with management programs that prioritized artificial insemination (AI) at detected estrus (AIE) or timed AI (TAI). Moreover, we aimed to determine whether subgroups of cows with different fertility potential would present a distinct response to the reproductive management strategies compared. Lactating primiparous Holstein cows (n = 6 commercial farms) were stratified into high (Hi-Fert), medium (Med-Fert), and low (Lo-Fert) genetic fertility groups (FG) based on a Reproduction Index value calculated from multiple genomic-enhanced predicted transmitting abilities. Within herd and FG, cows were randomly assigned either to a program that prioritized TAI and had an extended voluntary waiting period (P-TAI; n = 1,338) or another that prioritized AIE (P-AIE; n = 1,416) and used TAI for cows, not AIE. Cows in P-TAI received first service by TAI at 84 ± 3 d in milk (DIM) after a Double-Ovsynch protocol, were AIE if detected in estrus after a previous AI, and received TAI after an Ovsynch-56 protocol at 35 ± 3 d after a previous AI if a corpus luteum (CL) was visualized at nonpregnancy diagnosis (NPD) 32 ± 3 d after AI. Cows with no CL visualized at NPD received TAI at 42 ± 3 d after AI after an Ovsynch-56 protocol with progesterone supplementation (P4-Ovsynch). Cows in P-AIE were eligible for AIE after a PGF2α treatment at 53 ± 3 DIM and after a previous AI. Cows not AIE by 74 ± 3 DIM or by NPD 32 ± 3 d after AI received P4-Ovsynch for TAI at 74 ± 3 DIM or 42 ± 3 d after AI. Binary data were analyzed with logistic regression, count data with Poisson regression, continuous data by ANOVA, and time to event data by Cox's proportional hazard regression. Pregnancy per AI (P/AI) to first service was greater for cows in the Hi-Fert (59.8%) than the Med-Fert (53.6%) and Lo-Fert (47.7%) groups, and for the P-TAI (58.7%) than the P-AIE (48.7%) treatment. Overall, P/AI for all second and subsequent AI combined did not differ by treatment (P-TAI = 45.2%; P-AIE = 44.5%) or FG (Hi-Fert = 46.1%; Med-Fert = 46.0%; Lo-Fert = 42.4%). The hazard of pregnancy after calving was greater for the P-AIE than the P-TAI treatment [hazard ratio (HR) = 1.27, 95% CI: 1.17 to 1.37)], and for the Hi-Fert than the Med-Fert (HR = 1.16, 95% CI: 1.05 to 1.28) and Lo-Fert (HR = 1.34, 95% CI: 1.20 to 1.49) groups. More cows in the Hi-Fert (91.2%) than the Med-Fert (88.4%) and Lo-Fert (85.8%) groups were pregnant at 200 DIM. Within FG, the hazard of pregnancy was greater for the P-AIE than the P-TAI treatment for the Hi-Fert (HR = 1.41, 95% CI: 1.22 to 1.64) and Med-Fert (HR = 1.28, 95% CI: 1.12 to 1.46) groups but not for the Lo-Fert group (HR = 1.13, 95% CI: 0.98 to 1.31). We conclude that primiparous Holstein cows of superior genetic merit for fertility had better reproductive performance than cows of inferior genetic merit for fertility, regardless of the type of reproductive management used. In addition, the effect of programs that prioritized AIE or TAI on reproductive performance for cows of superior or inferior genetic merit for fertility depended on the outcomes evaluated. Thus, programs that prioritize AIE or TAI could be used to affect certain outcomes of reproductive performance or management.

Ovarian aging in humans: potential strategies for extending reproductive lifespan

Ovarian reserve is a term used to estimate the total number of immature follicles present in the ovaries. Between birth and menopause, there is a progressive decrease in the number of ovarian follicles. Ovarian aging is a continuous physiological phenomenon, with menopause being the clinical mark of the end of ovarian function. Genetics, measured as family history for age at the onset of menopause, is the main determinant. However, physical activity, diet, and lifestyle are important factors that can influence the age of menopause. The low estrogen levels after natural or premature menopause increased the risk for several diseases, resulting in increased mortality risk. Besides that, the decreasing ovarian reserve is associated to reduced fertility. In women with infertility undergoing in vitro fertilization, reduced markers of ovarian reserve, including antral follicular count and anti-Mullerian hormone, are the main indicators of reduced chances of becoming pregnant. Therefore, it becomes clear that the ovarian reserve has a central role in women's life, affecting fertility early in life and overall health later in life. Based on this, the ideal strategy for delaying ovarian aging should have the following characteristics: (1) be initiated in the presence of good ovarian reserve; (2) maintained for a long period; (3) have an action on the dynamics of primordial follicles, controlling the rate of activation and atresia; and (4) safe use in pre-conception, pregnancy, and lactation. In this review, we therefore discuss some of these strategies and its feasibility for preventing a decline in the ovarian reserve.

Evolution Under Dietary Restriction Increases Reproduction at the Cost of Decreased Somatic Growth

Dietary restriction (DR) is cited as the most reliable means of extending life span in a wide range of taxa, yet the evolutionary basis of the DR effect on life span remains unclear. The resource reallocation hypothesis proposes that the longevity-extending response of DR is adaptive and stems from the reallocation of resources from reproduction to somatic maintenance under food-limited conditions. However, if DR continues for multiple generations, such a response becomes maladaptive, and genotypes with higher fecundity should be selectively favored over genotypes with longer longevity. To test this prediction, we exposed replicate populations of the rotifer Brachionus dorcas, a model organism for aging and experimental evolution studies, to DR and ad-libitum (AL) diets for 100 days. During the selection experiment, AL-selected populations showed higher growth rates and mictic ratios than DR-selected populations. After approximately 27 asexual generations of selection, populations with a DR selection history had a higher net reproductive rate but lower body volume and ingestion rate in the absence of survival costs than populations with an AL selection history when they were assayed on an AL diet. Our results are inconsistent with the prediction that evolution on sustained DR increases reproduction and reduces life span, and show for the first time that sustained DR selects for clones with higher energy investment in reproduction but lower investment in somatic growth.

Twenty years of experience with less radical fertility-sparing surgery in early-stage cervical cancer: Pregnancy outcomes

INTRODUCTION

The standard procedure in cervical cancer is radical hysterectomy and pelvic lymphadenectomy (PLND). Because of the increasing age of women bearing children, fertility has become a major challenge. We present pregnancy results after less radical fertility-sparing surgery in women with IA1, LVSI positive, IA2 and IB1 (<2 cm, infiltration less than half of the cervical stroma).

MATERIALS AND METHOD

All women (n = 91) underwent laparoscopic sentinel lymph node mapping with frozen section followed by PLND and "selective parametrectomy" (removal of afferent lymphatic channels from the paracervix) if sentinel nodes (SLN) are negative. If lymph nodes were verified negative by definitive histopathology, patients were treated by simple trachelectomy (IB1) or large cone (IA1/IA2) biopsy 1 week after primary surgery.

RESULTS

From 1999 to 2018, 91 women were enrolled in the study (median age 29.1 years, range 21-40). Fertility was spared in 76 (83.5%) women; 13 (17.1%) women did not plan future pregnancy and 63 (82.9%) had pregnancy desires. Fifty-four of 63 women conceived (pregnancy rate 85.7%) and 48 of 63 delivered 58 babies (delivery rate 76.2%). Thirty-nine women delivered in term (67.2%): 13 women between 32 and 36 + 6 weeks of pregnancy, 3 between 28 and 31 + 6 weeks and 3 between 24 and 27 + 6 weeks. Only one woman still plans pregnancy. One woman is currently pregnant.

CONCLUSION

The goal of fertility-sparing surgery is to produce good oncological results and promising pregnancy outcomes. Pregnancy results after less radical fertility-sparing procedures show promise (pregnancy rate 82.9% and delivery rate 76.2%).

Sperm capacitation as a predictor of boar fertility

Prediction of a boar's fertility level has great economic importance for sow herds. After standard sperm morphology and motility metrics are met, approximately 25% of boars have less than 80% conception rates. Due in part to the many factors involved in the fertilization process, a multifactorial model incorporating multiple relevant sperm physiology factors will likely lead to increased understanding of boar fertility. Here we review the current literature on boar sperm capacitation as a predictor of boar fertility. While limited, several studies have provided correlations between the percentage of sperm in an ejaculate that are capable of undergoing sperm capacitation in a chemically defined media and artificial insemination field fertility as well as proteome and other methods. Work summarized here underscores the need for further understanding of boar fertility.

Screening for diminished ovarian reserve in Portugal: a cost-saving answer to shorten the fertility journey

Aim: Assess the budget impact of nationwide screening for diminished ovarian reserve (OR), via anti-Müllerian hormone (AMH) levels, to the Portugal National Health System (NHS). Patients & methods: The clinical journey was determined using literature and the family planning decision-making process/response using survey results. A panel of four local clinicians validated all assumptions/inputs. Results: Screening for OR led to an expected savings of € 9.4 million for the NHS, driven by a 24% reduction in medically assisted reproduction (MAR) use. When needed, referral for MAR was earlier and more women used first-line versus second-line techniques. The model estimated a 12% decrease in failure. Conclusion: This model shows AMH screening may allow more informed decisions, leading to a shorter fertility journey, more efficient use of treatments, and substantial cost-savings for the NHS.

Transcriptional programs are activated and microRNAs are repressed within minutes after mating in the Drosophila melanogaster female reproductive tract

BACKGROUND

The female reproductive tract is exposed directly to the male's ejaculate, making it a hotspot for mating-induced responses. In Drosophila melanogaster, changes in the reproductive tract are essential to optimize fertility. Many changes occur within minutes after mating, but such early timepoints are absent from published RNA-seq studies. We measured transcript abundances using RNA-seq and microRNA-seq of reproductive tracts of unmated and mated females collected at 10-15 min post-mating. We further investigated whether early transcriptome changes in the female reproductive tract are influenced by inhibiting BMPs in secondary cells, a condition that depletes exosomes from the male's ejaculate.

RESULTS

We identified 327 differentially expressed genes. These were mostly upregulated post-mating and have roles in tissue morphogenesis, wound healing, and metabolism. Differentially abundant microRNAs were mostly downregulated post-mating. We identified 130 predicted targets of these microRNAs among the differentially expressed genes. We saw no detectable effect of BMP inhibition in secondary cells on transcript levels in the female reproductive tract.

CONCLUSIONS

Our results indicate that mating induces early changes in the female reproductive tract primarily through upregulation of target genes, rather than repression. The upregulation of certain target genes might be mediated by the mating-induced downregulation of microRNAs. Male-derived exosomes and other BMP-dependent products were not uniquely essential for this process. Differentially expressed genes and microRNAs provide candidates that can be further examined for their participation in the earliest alterations of the reproductive tract microenvironment.

Review: Manipulation of follicle development to improve fertility of cattle in timed-artificial insemination programs

The development of an ovulatory follicle is a fundamental premise for any reproductive management program that aims to optimize fertility in cattle. Controlling follicular development comprises the synchronized emergence of a new follicular wave, selection and growth of the dominant follicle, and synchronized ovulation of a high-quality oocyte. All these follicular events, primarily driven by gonadotropin secretion, occur under a very dynamic hormonal environment. In this sense, controlling follicular development demands essentially a precise manipulation of the hormonal environment to modulate gonadotropin secretion. Furthermore, the effectiveness of hormonal manipulation strategies in the management of follicular development depends on specific particularities of each situation, which can vary widely according to genetic groups (Bos taurus vs Bos indicus), nutritional, metabolic, and reproductive status. In this regard, the constant search for the refined synchrony between the hormonal treatments and reproductive events, considering these distinctions and particularities, have provided valuable information that contributed to the development of efficient reproductive programs. This manuscript discusses the physiological bases behind the development of fine-tuned timed-artificial insemination protocols for beef and dairy cattle that resulted in great improvements in reproductive efficiency of beef and dairy herds.

Review: Reproductive consequences of whole-body adaptations of dairy cattle to heat stress

Heat stress has far-reaching ramifications for agricultural production and the severity of its impact has increased alongside the growing threats of global warming. Climate change is exacerbating the already-severe consequences of seasonal heat stress and is predicted to cause additional losses in reproductive performance, milk production and overall productivity. Estimated and predicted losses are staggering, and without advancement in production practices during heat stress, these projected losses will threaten the human food supply. This is particularly concerning as the worldwide population and, thus, demand for animal products grows. As such, there is an urgent need for the development of technologies and management strategies capable of improving animal production capacity and efficiency during periods of heat stress. Reproduction is a major component of animal productivity, and subfertility during thermal stress is ultimately the result of both reproductive and whole-body physiological responses to heat stress. Improving reproductive performance during seasonal heat stress requires a thorough understanding of its effects on the reproductive system as well as other physiological systems involved in the whole-body response to elevated ambient temperature. To that end, this review will explore the reproductive repercussions of whole-body consequences of heat stress, including elevated body temperature, altered metabolism and circulating lipopolysaccharide. A comprehensive understanding of the physiological responses to heat stress is a prerequisite for improving fertility, and thus, the overall productivity of dairy cattle experiencing heat stress.

hnRNPH1 establishes Sertoli-germ cell crosstalk through cooperation with PTBP1 and AR, and is essential for male fertility in mice

Spermatogenesis depends on the crosstalk of Sertoli cells (SCs) and germ cells. However, the gene regulatory network establishing the communications between SCs and germ cells remains unclear. Here, we report that heterogeneous nuclear ribonucleoprotein H1 (hnRNPH1) in SCs is essential for the establishment of crosstalk between SCs and germ cells. Conditional knockout of hnRNPH1 in mouse SCs leads to compromised blood-testis barrier function, delayed meiotic progression, increased germ cell apoptosis, sloughing of germ cells and, eventually, infertility of mice. Mechanistically, we discovered that hnRNPH1 could interact with the splicing regulator PTBP1 in SCs to regulate the pre-mRNA alternative splicing of the target genes functionally related to cell adhesion. Interestingly, we also found hnRNPH1 could cooperate with the androgen receptor, one of the SC-specific transcription factors, to modulate the transcription level of a group of genes associated with the cell-cell junction and EGFR pathway by directly binding to the gene promoters. Collectively, our findings reveal a crucial role for hnRNPH1 in SCs during spermatogenesis and uncover a potential molecular regulatory network involving hnRNPH1 in establishing Sertoli-germ cell crosstalk.

Fecundity and Longevity of Spodoptera frugiperda (Lepidoptera: Noctuidae) at Constant Temperatures and Development of an Oviposition Model

Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a notorious invasive pest native to subtropical and tropical regions in the Western Hemisphere. It has recently invaded and established in south Asian countries and in South Korea only seasonally. Longevity, survival, and fecundity of fall armyworm were examined at different temperatures (16, 20, 24, 28, and 32°C) and an oviposition model was developed. The maximum observed fecundity was 1,485 eggs per female at 22.0°C, which decreased to ca. 815 eggs at 32.0°C. Female longevity decreased as the temperature increased up to 24°C, and then was constant around 13-14 d until temperature reached 32°C, ranging from 33.1 d at 16.0°C to 13.1 d at 32.0°C. Temperature-dependent total fecundity (TDF) was well described by the extreme value function. Age-specific cumulative oviposition rate (AOR) and age-specific survival rate (ASR) curves were fitted to logistic and sigmoid functions, respectively. The model of female adults' aging rate (1/mean longevity) as a function of temperature was used to calculate the physiological age of fall armyworm females in AOR and ASR models. Three temperature-dependent components of TDF, AOR, and ASR were incorporated to construct the oviposition model, and it was simulated to project corn damage with tentative parameters. When 10 fall armyworm females were assumed, a total of 68-74 corn ears with kernel damage were predicted. Such loss was estimated to be US$75-83 currently in the Korean market.

Lower Plasmatic Levels of Saturated Fatty Acids and a Characteristic Fatty Acid Composition in the Ovary Could Contribute to the High-Fertility Phenotype in Dummerstorf Superfertile Mice

In recent decades, fertility traits in humans as well as in farm animals have decreased worldwide. As such, it is imperative to know more about the genetics and physiology of increased or high fertility. However, most of the current animal models with reproductive phenotypes describe lower fertility or even infertility (around 99%). The “Dummerstorf high-fertility lines” (FL1 and FL2) are two unique mouse lines selected for higher reproductive performances, more specifically for higher number of pups per litter. We recently described how those superfertile mice managed to increase their reproductive phenotype by doubling the ovulation rate and consequently the litter size compared to the unselected mice of the same founder population. FLs show an unusual estrous cycle length and atypical levels of hormones that link reproduction and metabolism, such as insulin in FL1 and leptin in FL2. Moreover, we described that their higher ovulation rate is mostly due to a higher quality of their oocytes rather than their sheer quantity, as they are characterized by a higher quantity of high-quality oocytes in antral follicles, but the quantity of follicles per ovary is not dissimilar compared to the control. In the present study, we aimed to analyze the lipid composition of the fertility lines from plasma to the gonads, as they can connect the higher reproductive performances with their metabolic atypicalities. As such, we analyzed the fat content of FLs and fatty acid composition in plasma, liver, fat, oocytes of different quality, and granulosa cells. We demonstrated that those mice show higher body weight and increased body fat content, but at the same time, they manage to decrease the lipid content in the ovarian fat compared to the abdominal fat, which could contribute to explaining their ovarian quality. In addition, we illustrate the differences in fatty acid composition in those tissues, especially a lower level of saturated fatty acids in plasma and a different lipid microenvironment of the ovary. Our ongoing and future research may be informative for farm animal biology as well as human reproductive medicine, mostly with cases that present characteristics of lower fertility that could be reversed following the way-of-managing of Dummerstorf high-fertility lines.

Tracking of menstrual cycles and prediction of the fertile window via measurements of basal body temperature and heart rate as well as machine-learning algorithms

BACKGROUND

Fertility awareness and menses prediction are important for improving fecundability and health management. Previous studies have used physiological parameters, such as basal body temperature (BBT) and heart rate (HR), to predict the fertile window and menses. However, their accuracy is far from satisfactory. Additionally, few researchers have examined irregular menstruators. Thus, we aimed to develop fertile window and menstruation prediction algorithms for both regular and irregular menstruators.

METHODS

This was a prospective observational cohort study conducted at the International Peace Maternity and Child Health Hospital in Shanghai, China. Participants were recruited from August 2020 to November 2020 and followed up for at least four menstrual cycles. Participants used an ear thermometer to assess BBT and wore the Huawei Band 5 to record HR. Ovarian ultrasound and serum hormone levels were used to determine the ovulation day. Menstruation was self-reported by women. We used linear mixed models to assess changes in physiological parameters and developed probability function estimation models to predict the fertile window and menses with machine learning.

RESULTS

We included data from 305 and 77 qualified cycles with confirmed ovulations from 89 regular menstruators and 25 irregular menstruators, respectively. For regular menstruators, BBT and HR were significantly higher during fertile phase than follicular phase and peaked in the luteal phase (all P < 0.001). The physiological parameters of irregular menstruators followed a similar trend. Based on BBT and HR, we developed algorithms that predicted the fertile window with an accuracy of 87.46%, sensitivity of 69.30%, specificity of 92.00%, and AUC of 0.8993 and menses with an accuracy of 89.60%, sensitivity of 70.70%, and specificity of 94.30%, and AUC of 0.7849 among regular menstruators. For irregular menstruators, the accuracy, sensitivity, specificity and AUC were 72.51%, 21.00%, 82.90%, and 0.5808 respectively, for fertile window prediction and 75.90%, 36.30%, 84.40%, and 0.6759 for menses prediction.

CONCLUSIONS

By combining BBT and HR recorded by the Huawei Band 5, our algorithms achieved relatively ideal performance for predicting the fertile window and menses among regular menstruators. For irregular menstruators, the algorithms showed potential feasibility but still need further investigation.

TRIAL REGISTRATION

ChiCTR2000036556. Registered 24 August 2020.

Mitigation of low pregnancy rate in excitable Nellore cows by administration of GnRH or P4

This research aimed to determine the effect of temperament on reproductive parameters including cortisol and progesterone (P4) in Nellore cows. Additionally, two methods for increasing plasma progesterone (P4) levels in excitable animals to enhance pregnancy rate (P/AI) and reduce pregnancy loss were investigated. In total, 939 cows were subjected to timed artificial insemination (TAI) and divided into three groups: (P4LA; n = 305) 150 mg of injectable long-acting progestogen 7 days after TAI; (GnRH; n = 306), 10 μg of buserelin acetate on day 7 after TAI; control group (CG; n = 328) without hormonal treatment. In 213 cows, randomly chosen from each group, ultrasound evaluations of the preovulatory follicle (Mode B) were performed on the day of insemination and of the corpus luteum (Color Doppler) 7 and 16 days after TAI. Blood samples were obtained from 20% of the 939 animals, randomly chosen from each group, on the day of insemination and after 7 and 16 days to measure cortisol and progesterone, respectively. At the time of insemination, subjective temperament evaluations were performed with the animals being classified as excitable (EXC) or adequate (ADQ). The SAS GLIMMIX procedure was used to compare the pregnancy rate (P/AI) and gestational loss within each temperament for the three experimental groups. Continuous variables were analyzed utilizing SAS PROC MIXED procedure. Cortisol concentration was higher and POF (preovulatory follicle) and CL (corpus luteum) volumes at the time of insemination and 7 days after AI, respectively, were lower in EXC animals than in ADQ. No significant difference was observed between the number of pixels, CL intensity, and plasma concentration of P4, 7 days after TAI. However, 16 days post-insemination, among the animals classified as EXC, higher concentrations of P4 were observed in the GnRH and P4LA groups than in the control. Regarding P4 concentrations, there was a tendency to be lower in animals classified as EXC than in ADQ within the control group (P = 0.06), while rate of blood flow from the CL was lower in EXC animals than in ADQ animals (P = 0.04). Among the ADQ animals, the GnRH and P4LA groups showed a lower CL flow rate than that observed in the control (P = 0.04), 16 days after the TAI. Among EXC animals, a higher pregnancy rate was observed in the GnRH and P4LA groups than in the control group (P = 0.01). In the control group, the pregnancy rate (P/AI) of the ADQ animals was higher than that of the EXC animals (P = 0.05). No statistically significant differences were observed between gestational losses when the treatments or temperaments were compared. In conclusion, the use of GnRH or P4LA, 7 days after insemination, improves pregnancy rates in excitable animals and is a viable alternative to minimize the negative impact of stress and improve reproductive efficiency in beef cattle.

How to manage weight loss in women with obesity and PCOS seeking fertility?

Obesity exacerbates the phenotype of polycystic ovarian syndrome (PCOS) including infertility as well as reducing the efficacy and access to fertility treatments. Weight management is, therefore, a key component of treatment for women with PCOS and coexistent obesity. Many women with PCOS describe significant difficulty losing weight and treatment options are limited. The first-line treatment is lifestyle interventions though the weight loss and any impact on fertility are limited. No one dietary strategy can be preferentially recommended based on current evidence. While very low energy diets can result in significant weight loss the evidence for impact on fertility is limited. Pharmacotherapy, including a range of treatments can result in marked weight loss and there is some evidence of improved rates of conception including spontaneous and in response to assisted reproduction treatment. As with pharmacotherapy, data regarding bariatric surgery is largely from nonrandomized studies and though the significant weight loss is anticipated to improve fertility the available data prevents firm conclusions. Clinicians and patients must consider the magnitude of weight loss to be targeted as well as the anticipated fertility treatment required and the timeline of treatment when deciding upon the personalized weight loss strategy. Clinicians and patients should be confident in targeting the most appropriate treatment early in the patient's management to avoid unnecessary delays.

New insights into sperm rheotaxis, agglutination and bundle formation in Sharkasi chickens based on an in vitro study

Fertility in birds is dependent on their ability to store adequate populations of viable sperm for extended durations in sperm storage tubules (SSTs). The exact mechanisms by which sperm enter, reside, and egress from the SSTs are still controversial. Sharkasi chicken sperm showed a high tendency to agglutinate, forming motile thread-like bundles comprising many cells. Since it is difficult to observe sperm motility and behavior inside the opaque oviduct, we employed a microfluidic device with a microchannel cross-section resembling close to that of sperm glands allowing for the study of sperm agglutination and motility behavior. This study discusses how sperm bundles are formed, how they move, and what role they may have in extending sperm residency inside the SSTs. We investigated sperm velocity and rheotaxis behavior when a fluid flow was generated inside a microfluidic channel by hydrostatic pressure (flow velocity = 33 µm/s). Spermatozoa tended to swim against the flow (positive rheotaxis) and sperm bundles had significantly lower velocity compared to lonesome sperm. Sperm bundles were observed to swim in a spiral-like motion and to grow in length and thickness as more lonesome sperm are recruited. Sperm bundles were observed approaching and adhering to the sidewalls of the microfluidic channels to avoid being swept with fluid flow velocity > 33 µm/s. Scanning and transmission electron microscopy revealed that sperm bundles were supported by a copious dense substance. The findings show the distinct motility of Sharkasi chicken sperm, as well as sperm's capacity to agglutinate and form motile bundles, which provides a better understanding of long-term sperm storage in the SSTs.

A Comparison of App-Defined Fertile Days from Two Fertility Tracking Apps using Identical Cycle Data

OBJECTIVE

The Natural Cycles app employs daily basal body temperature to define the fertile window via a proprietary algorithm and is clinically established effective in preventing pregnancy. We sought to i) compare the app-defined fertile window of Natural Cycles to that of CycleProGo™, an app that uses BBT and cervical mucus to define the fertile window and ii) compare the app-defined fertile windows to the estimated physiologic fertile window.

STUDY DESIGN

Daily BBT were entered into Natural Cycles from 20 randomly selected regularly cycling women with at least 12 complete cycles from the CycleProGo database. The proportion of cycles with equivalent (+/-1 cycle day) fertile-window starts and fertile-window ends was determined. The app -defined fertile windows were then compared to the estimated physiologic fertile window using Peak mucus to estimate ovulation.

RESULTS

Fifty seven percent of cycles (136/238) had equivalent fertile-window starts and 36% (72/181) had equivalent fertile-window end days. The mean overall fertile-window length from Natural Cycles was 12.8 days compared to 15.1 days for CycleProGo (p<0.001). The Natural Cycles algorithm declared 12%-30% of cycles with a fertile-window start and 13%-38% of cycles with a fertile-window end within the estimated physiologic fertile window. The CycleProGo algorithm declared 4%-14% of cycles with a fertile-window start and no cycles with a fertile-window end within the estimated physiologic fertile window.

CONCLUSIONS

Natural Cycles designated a higher proportion of cycles days as infertile within the estimated physiologic fertile window than CycleProGo.

IMPLICATIONS

Use of cervical mucus in addition to BBT may improve the accuracy of identifying the fertile window. Additional studies with other markers of ovulation and the fertile window would give additional insight into the clinical implications of app-defined fertile window differences.

Human fertility and sleep disturbances: A narrative review

INTRODUCTION

Many factors may be hidden behind the global fertility decline observed in Western countries. Alongside the progressively increased age of infertile couples, environmental and behavioural factors, including non-optimal lifestyle habits, should be considered. Among these, sleep disorders have been suggested to be linked to human fertility.

METHODS

This is a narrative review, describing first sleep physiology, its disturbances, and the tools able to quantify sleep dysfunction. Then, we consider all available studies aimed at investigating the connection between sleep disorders and human fertility, providing a comprehensive view on this topic.

RESULTS

Forty-two studies investigating the relationship between sleep habits and human reproduction were included. All the published evidence was grouped according to the aspect of human fertility considered, i.e. i) female reproductive functions, ii) male reproductive functions, iii) natural conception and iv) assisted reproduction. For each of the sub-groups considered, the connection between sleep dysregulation and human fertility was classified according to specific sleep characteristics, such as sleep duration, quality, and habits. In addition, possible physio-pathological mechanisms proposed to support the link between sleep and fertility were summarized.

CONCLUSION

This review summarizes the most relevant findings about the intricate and still largely unknown network of molecular pathways involved in the regulation of circadian homeostasis, to which sleep contributes, essential for reproductive physiology. Thus, many mechanisms seem correlate sleep disorders to reproductive health, such as adrenal activation, circadian dysregulation, and genetic influences. This review highlights the need to properly designed trials on the topic.