Hospital Admission, Cerebral Palsy, Intellectual Disability And Birth Defects In Assisted Conception Infants.
Funder
National Health and Medical Research Council
Funding Amount
$115,110.00
Summary
We have recently completed a study examining the prevalence of birth defects in assisted conception infants born in Western Australia from 1993-1997. Contrary to reassuring claims by other researchers in this area, we found that assisted conception infants have a two-fold increased risk of being diagnosed with a major birth defect by one year of age. We now propose to examine other long-term health outcomes in these children. This study involves record linkage between the WA Reproductive Technol ....We have recently completed a study examining the prevalence of birth defects in assisted conception infants born in Western Australia from 1993-1997. Contrary to reassuring claims by other researchers in this area, we found that assisted conception infants have a two-fold increased risk of being diagnosed with a major birth defect by one year of age. We now propose to examine other long-term health outcomes in these children. This study involves record linkage between the WA Reproductive Technology Register and four other population-based databases. The prevalence of cerebral palsy, intellectual disability, hospital admission and birth defects in assisted conception children born in WA between 1993 and 2001 will be compared to that seen in all other Western Australian children born over the same time period. The collection of information on risks associated with assisted conception treatment is vital to allow adequate counselling of couples considering fertility treatment. Cerebral palsy, intellectual disability, birth defects and hospital admission are all serious adverse health outcomes and, despite the introduction of IVF to most Western countries twenty years ago, there are limited data in the literature concerning the occurrence of these conditions in assisted conception infants. Quantifying the contribution of assisted conception treatment to neonatal, infant and childhood morbidity and mortality is also important for the planning of health service provision. Although assisted conception births represent only a small proportion of total births in Australia, these infants may require a disproportionate level of health care services, such as neonatal intensive care treatment due to complications associated with preterm or multiple birth. The wide application of assisted conception treatment in Australia and the increased number of pregnancies achieved by these means reinforce the urgent need for valid data on the health of children born after these procedures.Read moreRead less
The Role Of Transcription Factors In Regulating The First Round Of Gene Expression In The Early Embryo.
Funder
National Health and Medical Research Council
Funding Amount
$348,931.00
Summary
Assisted reproductive technologies result in a high incidence of multiple births. This is and adverse outcome that requires correction. It stems from the common transfer of several embryos due to the low chance of an individual embryo made by IVF resulting in a baby. This project will determine the normal pattern of gene expression in the embryo and define: (1) how it is adversely changed as a consequence of IVF; and (2) the extent that these changes are a cause of the low embryo viability.
Mechanisms Of P53 Induced Embryopathy After In Vitro Fertilisation.
Funder
National Health and Medical Research Council
Funding Amount
$483,737.00
Summary
Assisted reproductive technologies (ART) cause many embryos not to survive to birth. We have shown that IVF causes increased expression of protein normally involved in stopping cells from dividing. This is a major cause of embryo death after IVF. This project will determine how this protein acts to cause embryonic death and assess strategies to prevent it.
The normal processes of development of the embryo require that the information encoded in chromosomes be reprogrammed soon after fertilization. This process is rather fragile and disturbance of the early embryo can upset it. Recent studies for the chief investigator's provide new understanding of the normal processes of reprogramming. The project will explore and validate the implications of these new discoveries and provide a basis for future alleviation of abnormalities to development.
We propose to determine if a recently discovered biological mechanism plays crucial roles in the development of eggs and sperm. To achieve this, we will remove or mutate this pathway specifically in developing eggs and sperm , then examine the effect. Preliminary results indicate that the mechanism does play important roles mutated eggs fail to complete maturation. These studies will tell us more about what makes a healthy egg and sperm, and are relevant to female and male fertility.
Male Infertility And Defective Sperm-oocyte Interaction
Funder
National Health and Medical Research Council
Funding Amount
$244,614.00
Summary
Infertility affects 15% of people and although not usually ill, they are extremely distressed by the condition. In vitro fertilisation (IVF) with normal sperm and intracytoplasmic sperm injection for sperm defects, can assist such patients have a family, but these treatments are expensive and not always successful. The causes of male infertility are largely unknown, diagnostic methods are crude and there is usually no treatment to promote natural conception. Conventional semen analysis provides ....Infertility affects 15% of people and although not usually ill, they are extremely distressed by the condition. In vitro fertilisation (IVF) with normal sperm and intracytoplasmic sperm injection for sperm defects, can assist such patients have a family, but these treatments are expensive and not always successful. The causes of male infertility are largely unknown, diagnostic methods are crude and there is usually no treatment to promote natural conception. Conventional semen analysis provides limited information on fertilising ability. Our work over 15 years has shown that many patients go undiagnosed, particularly those with defects impairing fertilisation. During human fertilisation, sperm bind to the zona pellucida, a coat around the egg, via the membrane over a cap like structure on the sperm head called the acrosome. Binding of a sperm triggers the acrosome reaction, the process by which the membranes covering the acrosome fuse and the acrosomal contents are released. The sperm then penetrates the zona pellucida, binds to the membrane of the egg and is taken into the cytoplasm. We have developed tests to assess sperm binding to the zona pellucida and the acrosome reaction using eggs that failed to fertilise during clinical IVF. These tests show defects of sperm binding to the zona pellucida and the zona pellucida induced acrosome reaction are present in over 25% of patients without other obvious causes for their infertility. The men are severely infertile but have normal sperm by conventional tests. In this project we will determine if there are changes in membrane proteins in sperm which do not bind to the zona pellucida or undergo the acrosome reaction. We will categorise patients on the responses of their sperm to activation of key enzymes and other regulatory molecules involved in the fertilisation process. This will allow us to select subjects for further examination of protein abnormalities and genetic causes of the conditions.Read moreRead less
Comparison Of Pregnancy Outcomes Following Transferring One Or Two Embryos In A Selected Group Of Infertility Patients.
Funder
National Health and Medical Research Council
Funding Amount
$120,302.00
Summary
Assisted reproductive technology (ART) deals with issues of fundamental importance to individuals involved, and society as a whole. Despite major advances, ART continues to be very costly in many regards. A major reason for this is the relatively low rate of pregnancy, which averages 25% per procedure. The common response to the problem of low pregnancy rates is to return several embryos to uterus. A dilemma associated with this strategy is the high risk of multiple pregnancy, which is associate ....Assisted reproductive technology (ART) deals with issues of fundamental importance to individuals involved, and society as a whole. Despite major advances, ART continues to be very costly in many regards. A major reason for this is the relatively low rate of pregnancy, which averages 25% per procedure. The common response to the problem of low pregnancy rates is to return several embryos to uterus. A dilemma associated with this strategy is the high risk of multiple pregnancy, which is associated with adverse consequences for mother and fetus(es). Compared to singleton births; fetal, neonatal, and perinatal mortality rates are 3-6 times higher in twins, and 5-15 times higher in multiple births of a higher order. Cerebral palsy rates among survivors are six times higher in twins and twenty times higher in triplets. The increase in the incidence of adverse outcomes related to multiple pregnancy has been well documented in ART. We propose a randomised controlled study to assess single embryo transfer (SET) compared to double embryo transfer (DET). Infertility women with a high risk of multiple pregnancy will be randomly allocated to receive one or two embryos, which is the usual treatment at present. We shall then examine the rates of single and multiple pregnancies, and the success of those pregnancies in this group of patients. Potential benefits to the community from this project are very substantial, as it has the capacity to substantially reduce the number of multiple births. Patients will also benefit by having more accurate information with which to make an informed choice during treatment.Read moreRead less
Characterisation Of A Signal Transduction Pathway In The Early Embryo
Funder
National Health and Medical Research Council
Funding Amount
$208,500.00
Summary
The creation of embryos in the lab is important in assisted reproductive technology (ART) and potentially in cell therapies using embryonic stem cells. Yet, the development of the early embryo is not well understood. Creation of embryos in the lab is expensive and much of this cost is related to the relative inefficiency of the technology due to the high mortality of the resulting embryos. Typically, 45 - 80% of embryos produced by ART do not survive the first week. Hormones are essential chemic ....The creation of embryos in the lab is important in assisted reproductive technology (ART) and potentially in cell therapies using embryonic stem cells. Yet, the development of the early embryo is not well understood. Creation of embryos in the lab is expensive and much of this cost is related to the relative inefficiency of the technology due to the high mortality of the resulting embryos. Typically, 45 - 80% of embryos produced by ART do not survive the first week. Hormones are essential chemical messengers that regulate the normal functions of the body. Early embryo development is dependent on the action of special hormones that are produced by the embryonic cells themselves. The actions of these hormones are necessary for their normal survival. ART compromises the production and action of several of these hormones. Currently, there is not a detailed picture of how these embryonic hormones act on the embryo to promote their survival. Cells respond to outside hormones by changing the activity of a number intracellular proteins that act as on-off switches. The combinatorial pattern of 'switch' settings is modified by hormones, which in turn can act to change the pattern of gene expression. This project will extend our extensive studies on the nature of action of the well-described embryonic hormone known as PAF. The mechanism by which this hormone acts to signal changes in the pattern of the embryo's gene expression will be investigated. An understanding of how these embryonic hormones work will in the future allow for significant improvements in embryo viability.Read moreRead less
Role Of Tumour Suppressor Genes In Early Embryopathy
Funder
National Health and Medical Research Council
Funding Amount
$408,000.00
Summary
Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. 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. The high mortality of the early embryo seems to be a general feature of ART but its causes and effectors are incompletely defined. It has been established that this high mortality is largely due to a marked retardation in ....Assisted reproductive technologies (ART, such as IVF and related techniques) are successful treatments for most forms of infertility. 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. The high mortality of the early embryo seems to be a general feature of ART but its causes and effectors are incompletely defined. It has been established that this high mortality is largely due to a marked retardation in the rate of cell cycle progression by embryo cells, and commonly is associated with a form of cell 'suicide', known as apoptosis. In non-embryonic cells a group of genes known as the tumour suppressor genes (TSGs) are responsible for slowing cell-cycle progression and are commonly involved in inducing apoptosis following cell stress. The role of TSGs in the early embryo is not well studied. We have recently shown that the most important of the TSGs, P53, is normally kept at very low levels in the early embryo but that ART causes up-regulation of its expression. This upregulation is a major cause of the embryopathy associated with ART in an animal model but that genetic mutations that prevent P53 expression favours increased embryo development and viability. This project will examine whether ART also causes up-regulation other important TSGs and whether this occurs in human embryos. We will examine the hypothesis that ART increases the survival of embryos with mutations to the P53 gene (creating a postive genetic selection pressure in favour of these mutations); and which aspects of ART cause this positive selection. The project will demonstarte whether changes in the ART procedures have the potential to mitigate against selection of embryos bearing deletrious mutations.Read moreRead less
MECHANISMS OF ABNORMAL EXPRESSION OF THE IGF2 GENE IN DISORDERS AFFECTING FOETAL GROWTH
Funder
National Health and Medical Research Council
Funding Amount
$560,434.00
Summary
The IGF2 gene is crucial for foetal growth. Only the copy inherited from the father is active, a phenomenon named parental imprinting. In some children with foetal overgrowth or growth retardation, the deregulation of imprinting of the IGF2 gene during the first days of foetal development will influence subsequent growth and will also have major implications in post-natal and adult life. We will investigate the mechanisms resulting in abnormal imprinting of the IGF2 early in development.