Neuroendocrine Mechanisms By Which Leptin Regulates Reproduction
Funder
National Health and Medical Research Council
Funding Amount
$447,750.00
Summary
The reproductive system is sensitive to alterations in body weight. In particular, low body weight causes the reproductive system to cease functioning. This is because the brain 'senses' metabolic status and responds by ceasing to secrete the brain hormone that drives the reproductive process. This hormone is gonadotropin releasing hormone that acts on the pituitary gland to control the release of gonadotropins. These, in turn, act on the gonads. How the brain perceives metabolic status is not k ....The reproductive system is sensitive to alterations in body weight. In particular, low body weight causes the reproductive system to cease functioning. This is because the brain 'senses' metabolic status and responds by ceasing to secrete the brain hormone that drives the reproductive process. This hormone is gonadotropin releasing hormone that acts on the pituitary gland to control the release of gonadotropins. These, in turn, act on the gonads. How the brain perceives metabolic status is not known. Leptin is a hormone that is produced by fat and acts on the brain. This appears to be one of the means by which the reproductive system is regulated. Leptin also regulates food intake and other brain processes. Leptin acts on specific cell types in the brain. Some of these may have dual function to regulated appetite as well as reproduction. The present proposal is for work to determine mechanisms within the brain that are altered by leptin. We will also determine which specific mechanisms relate to the regulation of gonadotropin releasing hormone. The work will provide information on how putative appetite regulators might affect the reproductive axis. Such work will provide a platform for design of pharmaceutical means to manipulate the reproductive axis and will impact on the design of drugs that regulate obesity. It is possible that drugs that developed to control obesity may affect the reproductive axis and the project will identify these.Read moreRead less
Functional Genomic Analysis Of The Role Of P53 In Early Embryo Death After Assisted Reproductive Technologies (ART).
Funder
National Health and Medical Research Council
Funding Amount
$227,036.00
Summary
Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. ART are expensive therapies and much of this cost is related to the relative inefficiency of the technology. Much of this is due to the high mortality of the resulting embryos. Typically, 45-80% of embryos produced by ART do not survive the first week. Consequently the chance of any individual embryo resulting in a successful birth is not high. There has been only ....Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. ART are expensive therapies and much of this cost is related to the relative inefficiency of the technology. Much of this is due to the high mortality of the resulting embryos. Typically, 45-80% of embryos produced by ART do not survive the first week. Consequently the chance of any individual embryo resulting in a successful birth is not high. There has been only modest increments in embryo survival in recent years. The low cahnce of individual embryos resulting in a baby means that: (1) generally several treatment cycles are required; (2) superovulation is used to maximise the number of embryos produced giving an accumulation of unwanted cryopreserved embryos; (3) more than one embryo is generally transferred resulting in a significant incidence of multiple pregancies. The high mortality of the early embryo seems to be a general feature of IVF but its causes and effectors are not known. It has recently been established that it largely occurs due to a form of cell 'suicide' known as apoptosis. This form of cell death has important normal functions: its activation allows for cells that are no longer required to be removed, allowing the remodelling of tissues and it also serves to remove cells that are irreversibly damaged. p53 is a protein that has the ability to 'sense' cell stress and damage and to direct the cell to undergo apoptosis if the stress is severe. This project will examine if ART cause increased expression of p53 and whether this elevation of p53 causes embryonic cell death. We will examine the factirs that control p53 expression in the embryo. using mice with mutations that stop the function of p53 and several of its regulatory proteins. Experiments will determine the susceptibility of embryos possessing these mutations and will therefore allow us to define the proteins causing apoptosis after ART.Read moreRead less
Risk Of Birth Defects In Children Born Following Infertility Treatment
Funder
National Health and Medical Research Council
Funding Amount
$191,962.00
Summary
The development of assisted reproductive technology (ART) for infertility treatment has advanced at a tremendous pace since late 1970's. The use of ART is becoming increasingly frequent, with Australia having one of the highest rates of use internationally. Over 4,000 births result from ART annually in Australia. At the same time, minimally invasive infertility treatment-ovulation induction and insemination, remains a main option for some infertile couples and also generates several thousand bir ....The development of assisted reproductive technology (ART) for infertility treatment has advanced at a tremendous pace since late 1970's. The use of ART is becoming increasingly frequent, with Australia having one of the highest rates of use internationally. Over 4,000 births result from ART annually in Australia. At the same time, minimally invasive infertility treatment-ovulation induction and insemination, remains a main option for some infertile couples and also generates several thousand births annually. A fundamental concern for those involved in infertility treatment is the health of the children born following the treatment. Evidence from many studies indicates that compared to the general population, ART babies are more likely to be a twin or triplet, have a low birth weight, be born premature, and suffer higher rates of perinatal death and cerebral palsy. These issues are gradually being addressed by transferring a single embryo in a cycle. Of greater concern is the recent reporting by a Western Australian team that the risk of major birth defects is doubled in ART children. This is a highly significant finding that has raised concern in patients and clinicians. It is imperative to verify the findings through replication in a larger study. It is equally important to identify whether the increased risk is due to potentially modifiable treatment factors or patient factors related to their infertility. This innovative study will therefore also separate patient characteristics and type of treatment, and partition the risk attributable to various factors. The health of children from infertility treatments is of fundamental concern and has become an important public health issue. This study will direct future basic research in embryology and clinical services where there is a continual need to balance technical innovation and efficacy with treatment safety. The long-term benefit will be improvement of the health status of Australian families.Read moreRead less
Molecular Characterization Of Unique Recognition Sites On The Surface Of Human Spermatozoa
Funder
National Health and Medical Research Council
Funding Amount
$212,036.00
Summary
Developing an understanding of the molecular mechanisms that regulate human sperm function is central to the clinical management of male infertility, attempts to develop novel forms of male contraception and strategies for the introduction of transgenes into the male germ line. Defective sperm function is the largest single defined cause of human infertility. Despite the prevalence of this condition we have no idea how most cases of male infertility arise nor, in a vast majority of patients, do ....Developing an understanding of the molecular mechanisms that regulate human sperm function is central to the clinical management of male infertility, attempts to develop novel forms of male contraception and strategies for the introduction of transgenes into the male germ line. Defective sperm function is the largest single defined cause of human infertility. Despite the prevalence of this condition we have no idea how most cases of male infertility arise nor, in a vast majority of patients, do we understand which particular aspect of sperm biochemistry is defective. As a consequence we have not been able to develop sensitive biochemical diagnostic tests for the infertile male nor do we have any rational methods of treatment that address the cause of this condition. Similarly no new methods of male fertility regulation have been introduced since vasectomy despite the major advances that have been made in the field of female contraception over the same period of time. Clearly if we are to develop sensitive methods for the diagnosis of defective sperm function, introduce protocols for the treatment and prevention of male infertility and discover novel approaches to male contraception, we must first understand the cellular mechanisms that enable these highly specialized cells to perform their unique function. In this study we shall focus on one of the most important attributes of sperm function the capacity of these cells to recognize the egg. Once the biochemical basis of this fundamental recognition process is understood, it should pave the way for the development of clinical applications that target this signaling system with implications for a range of disciplines including reproductive toxicology, occupational medicine, family planning, infertility and biotechnology.Read moreRead less
The Role Of Growth Differentiation Factor 9 (GDF9) In Human Fertility
Funder
National Health and Medical Research Council
Funding Amount
$568,811.00
Summary
IVF comes at a substantial financial burden to the Australia health system through Medicare. There is mounting evidence to suggest that egg quality is the key limiting factor in female fertility. The aim of this proposal is to produce a key egg-secreted protein which is critical for the ability of the egg to be fertilized and to develop a diagnostic assay to measure egg quality to improve the treatment of infertility.
Isolation And Function Of Human Oogenesis Genes Regulating Meiosis, Recruitment, Growth And Maturation Of The Oocyte.
Funder
National Health and Medical Research Council
Funding Amount
$211,527.00
Summary
Reproductive medicine has progressed very rapidly with the development of in vitro fertilization (IVF) and has delivered the opportunity for a broad group of infertile couples to form their own families. As a consequence, treatment of infertility by major surgery and artificial insemination with donor sperm have declined and there is an increasing interest in the use of IVF to diagnose severe genetic disease in embryos of families at risk. However, little is known about the underlying processes ....Reproductive medicine has progressed very rapidly with the development of in vitro fertilization (IVF) and has delivered the opportunity for a broad group of infertile couples to form their own families. As a consequence, treatment of infertility by major surgery and artificial insemination with donor sperm have declined and there is an increasing interest in the use of IVF to diagnose severe genetic disease in embryos of families at risk. However, little is known about the underlying processes that form the follicles containing the developing germ cells and the matured oocytes needed for IVF. The cohort of oocytes that can be harvested from any patient depends on unknown recruitment processes initiating development of a subset of the quiescent germ cells and happens in an unregulated and spontaneous manner. The present project will identify the known and unknown genes involved in recruitment of oocytes from the basal primordial population. These genes will become candidates for aiding infertile women, improving their response to fertility drugs, the development of novel contraceptive methods and potentially increasing the reproductive life span of women. Knowledge of the genes expressed in oocytes matured in vivo and in vitro will have an important bearing on the long-term opportunity to use fertility drugs in vitro instead of administration to patients for IVF. This would dramatically reduce the cost of IVF and the side-effects of hyperstimulation of ovaries of patients and the associated sequelae. The research project is a discovery program leading to the identification of the genes that govern oogenesis in the human. It is only recently that techniques have been developed to sufficient sensitivity to detect the small quantities of RNA proceeded by active genes in the individual germ cells and oocytes.Read moreRead less
Molecular Mechanisms Regulating Spontaneous Onset Of Human Labour
Funder
National Health and Medical Research Council
Funding Amount
$481,156.00
Summary
The single most important complication contributing to poor pregnancy and neonatal outcome is premature birth. If we are to provide the best possible start to life, improve perinatal health and reduce the risk of developing adult disease . A better understanding of labour is requisite to improving health care delivery during pregnancy and outcomes for both mother and baby. This reserach project will investigate the how labour-associated events are reguluated by nuclear proteins.
The Mechanisms That Regulate The Onset Of Human Labour And Delivery
Funder
National Health and Medical Research Council
Funding Amount
$528,170.00
Summary
Reproductive biologists still cannot explain the molecular mechanisms that govern human birth. This lack of knowledge prevents the development of better moitoring and treament of complications of labour and delivery. If we are to provide the best possible start to life and improve newborn health care delivery then we must: (1) better understand what triggers labour; (2) determine whether there are biomarkers that we can use to identify women at risk of early birth; and (3) identify new ways to d ....Reproductive biologists still cannot explain the molecular mechanisms that govern human birth. This lack of knowledge prevents the development of better moitoring and treament of complications of labour and delivery. If we are to provide the best possible start to life and improve newborn health care delivery then we must: (1) better understand what triggers labour; (2) determine whether there are biomarkers that we can use to identify women at risk of early birth; and (3) identify new ways to delay birth. This is the overall objective of this research project. In particular, this project focuses on how the multiple events needed to achieve a successful outcome to pregnancy are coordinated at the time of birth.Read moreRead less
Immunobiology Of Early Pregnancy - A Model Of Virus-induced Abortion
Funder
National Health and Medical Research Council
Funding Amount
$454,500.00
Summary
The lack of 'self' molecule expression on the trophoblast cells of the placenta which interface directly with the mother's circulation, as well as the local suppression of the mother's immune response at this interface, may be important factors in the successful implantation of the embryo. This immunological 'silence' allows the embryo, whose paternal genetic contribution makes it immunologically foreign to the mother, to escape the rejection reaction normally associated with foreign graft trans ....The lack of 'self' molecule expression on the trophoblast cells of the placenta which interface directly with the mother's circulation, as well as the local suppression of the mother's immune response at this interface, may be important factors in the successful implantation of the embryo. This immunological 'silence' allows the embryo, whose paternal genetic contribution makes it immunologically foreign to the mother, to escape the rejection reaction normally associated with foreign graft transplantation. Infection with flaviviruses increases the concentrations of cell surface self and adhesion molecules in vertebrate cells, including the trophoblast cells of the placenta. As a result, these molecules can then be recognised by the maternal immune system and the embryo targeted for destruction. We hypothesise that the induction of these molecules by this and other viruses may break the immunological silence of the early embryo and reverse the local suppression of the maternal immune response. This would result in maternal immune rejection of the embryo and abortion. This initial sensitisation of the mother by the virus might be one of the reasons that some women suffer recurrent abortions. We will use a novel viral mouse model where we implant virus-infected embryos into receptive animals to enable us to dissect out the unusual requirements for induction of maternal anti-viral immunity during pregnancy. This model was developed in our laboratory to directly test our hypotheses. It does not cause systemic illness in the mother which itself can lead to non-specific abortion. This model therefore can for the first time elucidate the specific mechanisms associated with the delicate balance between eradicating virus and maintaining pregnancy. Results from this project will inform rational design of treatment of recurrent abortions in the community.Read moreRead less