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INTRODUCTION - Sickle cell disease (SCD) represents one of the most common monogenic blood disorders worldwide, with an incidence of over 300,000 newborns affected per year. Reproductive challenges for men and women with SCD have been previously reviewed; however, evidence-based strategies to prevent and manage infertility and increase fecundity are lacking in women with SCD, which is one of the most important factors for quality of life. Areas covered: This review article summarizes the known risk factors for infertility, low fecundity, and premature menopause related to SCD. Expert commentary: Women with SCD have unique risk factors that may impact their ability to conceive, including chronic inflammation, oxidative stress, transfusion-related hemochromatosis, and ovarian sickling, causing ischemia and reperfusion injury to the ovary. Contraception is strongly recommended while on hydroxyurea therapy during reproductive years and discontinuing hydroxyurea for family planning and during pregnancy based on teratogenicity in animal studies. Hematopoietic stem cell transplantation (HSCT), the only curative therapy, sometimes involves conditioning regimens containing alkylating agents and total body irradiation that contribute to infertility and premature ovarian failure. Prior to HSCT or gene therapy, we strongly recommend referral to a reproductive endocrinologist to discuss fertility preservation and surrogacy options for all women with SCD.
Fertility traits in humans are heritable, however, little is known about the genes that influence reproductive outcomes or the genetic variants that contribute to differences in these traits between individuals, particularly women. To address this gap in knowledge, we performed an unbiased genome-wide expression quantitative trait locus (eQTL) mapping study to identify common regulatory (expression) single nucleotide polymorphisms (eSNPs) in mid-secretory endometrium. We identified 423 cis-eQTLs for 132 genes that were significant at a false discovery rate (FDR) of 1%. After pruning for strong LD (r2 >0.95), we tested for associations between eSNPs and fecundability (the ability to get pregnant), measured as the length of the interval to pregnancy, in 117 women. Two eSNPs were associated with fecundability at a FDR of 5%; both were in the HLA region and were eQTLs for the TAP2 gene (P = 1.3x10-4) and the HLA-F gene (P = 4.0x10-4), respectively. The effects of these SNPs on fecundability were replicated in an independent sample. The two eSNPs reside within or near regulatory elements in decidualized human endometrial stromal cells. Our study integrating eQTL mapping in a primary tissue with association studies of a related phenotype revealed novel genes and associated alleles with independent effects on fecundability, and identified a central role for two HLA region genes in human implantation success.
Pituitary gonadotropins follicle-stimulating hormone and luteinizing hormone are heterodimeric glycoproteins expressed in gonadotropes. They act on gonads and promote their development and functions including steroidogenesis and gametogenesis. Although transcriptional regulation of gonadotropin subunits has been well studied, the post-transcriptional regulation of gonadotropin subunits is not well understood. To test if microRNAs regulate the hormone-specific gonadotropin β subunits in vivo, we deleted Dicer in gonadotropes by a Cre-lox genetic approach. We found that many of the DICER-dependent microRNAs, predicted in silico to bind gonadotropin β subunit mRNAs, were suppressed in purified gonadotropes of mutant mice. Loss of DICER-dependent microRNAs in gonadotropes resulted in profound suppression of gonadotropin-β subunit proteins and, consequently, the heterodimeric hormone secretion. In addition to suppression of basal levels, interestingly, the post-gonadectomy-induced rise in pituitary gonadotropin synthesis and secretion were both abolished in mutants, indicating a defective gonadal negative feedback control. Furthermore, mutants lacking Dicer in gonadotropes displayed severely reduced fertility and were rescued with exogenous hormones confirming that the fertility defects were secondary to suppressed gonadotropins. Our studies reveal that DICER-dependent microRNAs are essential for gonadotropin homeostasis and fertility in mice. Our studies also implicate microRNAs in gonadal feedback control of gonadotropin synthesis and secretion. Thus, DICER-dependent microRNAs confer a new layer of transcriptional and post-transcriptional regulation in gonadotropes to orchestrate the hypothalamus-pituitary-gonadal axis physiology.
© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
Hydroxyurea therapy, a chemotherapeutic agent, is the only US FDA approved therapy for the prevention of vaso-occlusive pain in sickle cell disease (SCD). The National Institutes of Health has sponsored two Phase III randomized, placebo-controlled trials, initially in adults, and subsequently in children with sickle cell anemia (SCA). Despite the overwhelming evidence that hydroxyurea therapy is beneficial to children and adults with SCA, individuals with SCA and their families express reservations about its use, in part because of the concerns about fertility, particularly in men. As adolescent boys with SCD are now expected to reach their reproductive years, a new concern is emerging about the role of hydroxyurea therapy as a barrier to their progeny. This review will systemically evaluate compromised fertility in men with SCD, and the evidence that hydroxyurea therapy is associated with further decreasing fertility in men with SCD.
TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly known as dioxin) is a ubiquitous environmental contaminant and known endocrine disruptor. Using a mouse model, we previously found that adult female mice exposed in utero to TCDD (F1 generation) as well as multiple subsequent generations (F2-F4) exhibited reduced fertility and an increased incidence of spontaneous preterm birth. Additional studies revealed that male F1 mice with a similar in utero/developmental TCDD exposure also exhibited diminished fertility and conferred an increased risk of preterm birth to their unexposed mating partners. Herein, we extend these previous observations, reporting that reduced fertility in male F1 mice is linked to testicular inflammation which coincides with apoptosis of developing spermatocytes, sub-fertility and an increased risk of preterm birth in their unexposed mating partners. Significantly, in the absence of additional toxicant exposure, testicular inflammation and reduced fertility persisted in F2 and F3 males and their control mating partners also frequently exhibited spontaneous preterm birth. Although a steady, global decline in male fertility has been noted over the last few decades, the reasons for these changes have not been firmly established. Likewise, the PTB rate in the U.S. and other countries has paralleled industrial development, suggesting a possible relationship between environmental toxicant exposure and adverse pregnancy outcomes. Most current clinical strategies to prevent preterm birth are focused solely on the mother and have yielded limited benefits. In contrast, our studies strongly suggest that the preconception testicular health of the father is a critical determinant of pregnancy outcomes in mice. Future clinical studies should examine the potential contribution of the male to gestation length in women and whether efforts to reduce the incidence of preterm birth should be initiated in both parents prior to pregnancy.
The NCCN Guidelines Insights on Adolescent and Young Adult (AYA) Oncology discuss the fertility and endocrine issues that are relevant to the management of AYA patients with cancer. Fertility preservation should be an essential part in the treatment of AYA patients with cancer. The NCCN Guidelines recommend discussion of fertility preservation and contraception before the start of treatment. Oophoropexy and embryo cryopreservation are the 2 established options for fertility preservation in women. Semen cryopreservation before the start of treatment is the most reliable and well-established method of preserving fertility in men. AYA women with cancer also have unique contraception needs, depending on the type of cancer, its treatment, and treatment-related complications. Management of cancer during pregnancy poses significant diagnostic and therapeutic challenges for both the patient and the physician. AYA women diagnosed with cancer during pregnancy require individualized treatment from a multidisciplinary team involving medical, surgical, radiation, and gynecologic oncologists; obstetricians; and perinatologists.
Preconception counseling provides an opportunity for health care providers to promote maternal and neonatal health, and to make recommendations regarding the optimization of natural fertility. While educating patients on the negative impact of maternal obesity on fertility and maternal and neonatal health; many health care providers recommend weight loss to reduce these negative outcomes. The recommendations start with lifestyle modifications, including diet and exercise. This article focuses on the available evidence regarding lifestyle modifications and fertility, and on the type of lifestyle modifications that health care providers should recommend to patients seeking to optimize their natural fertility.
Copyright © 2012. Published by Elsevier Inc.
A genetic bottleneck explains the marked changes in mitochondrial DNA (mtDNA) heteroplasmy that are observed during the transmission of pathogenic mutations, but the precise timing of these changes remains controversial, and it is not clear whether selection has a role. These issues are important for the genetic counseling of prospective mothers and for the development of treatments aimed at disease prevention. By studying mice transmitting a heteroplasmic single-base-pair deletion in the mitochondrial tRNA(Met) gene, we show that the extent of mammalian mtDNA heteroplasmy is principally determined prenatally within the developing female germline. Although we saw no evidence of mtDNA selection prenatally, skewed heteroplasmy levels were observed in the offspring of the next generation, consistent with purifying selection. High percentages of mtDNA genomes with the tRNA(Met) mutation were linked to a compensatory increase in overall mitochondrial RNA levels, ameliorating the biochemical phenotype and explaining why fecundity is not compromised.
Cancer is the leading cause of death among the adolescent and young adult (AYA) population, excluding homicide, suicide, or unintentional injury. AYA patients should be managed by a multidisciplinary team of health care professionals who are well-versed in the specific developmental issues relevant to this patient population. The recommendations for age-appropriate care outlined in these NCCN Guidelines include psychosocial assessment, a discussion of infertility risks associated with treatment and options for fertility preservation, genetic and familial risk assessment for all patients after diagnosis, screening and monitoring of late effects in AYA cancer survivors after successful completion of therapy, and palliative care and end-of-life considerations for patients for whom curative therapy fails.
BACKGROUND - Previous research suggests the removal of uterine leiomyomata may improve ability to conceive. Most of this previous research was conducted in infertility clinics. We investigated the association between leiomyoma characteristics on time to pregnancy among women enrolled from the general population.
METHODS - We enrolled a cohort study of women in early pregnancy. Participants retrospectively reported their time to conception. Leiomyomata characteristics were determined by first-trimester ultrasound. We used discrete time hazard models to estimate the effects of uterine leiomyomata on time to pregnancy.
RESULTS - In this population of 3000 women, 11% (324) with one or more leiomyomata, we found no association between leiomyomata presence, type, location, segment or size on time to pregnancy.
CONCLUSIONS - These results suggest that leiomyomata have little effect on time to pregnancy in this cohort of women. The study excluded women who had been treated for infertility, and this may have resulted in underestimation of the association. However, differences between our study and previous studies in specialty clinics may be, in part, attributable to differences between our community-recruited population of women and women receiving fertility care, as well as difference in leiomyomata size or type in women having myomectomies to treat infertility.