Neurosteroid Mediated Protection After Birth: Approaches For Maximising Protective Steroid Levels In The Neonatal Brain
Funder
National Health and Medical Research Council
Funding Amount
$450,703.00
Summary
Complications during pregnancy, birth asphyxia or premature birth can lead to neurological impairment in the newborn. Despite excellent neonatal care many of these babies go on to have serious handicaps. Neurosteroids are a group of steroids that regulate brain activity. These steroids protect brain cells from damage caused by an inadequate supply of oxygen by suppressing toxicity caused by excessive activity. We have shown that the levels of these protective steroids are remarkably high in the ....Complications during pregnancy, birth asphyxia or premature birth can lead to neurological impairment in the newborn. Despite excellent neonatal care many of these babies go on to have serious handicaps. Neurosteroids are a group of steroids that regulate brain activity. These steroids protect brain cells from damage caused by an inadequate supply of oxygen by suppressing toxicity caused by excessive activity. We have shown that the levels of these protective steroids are remarkably high in the fetal brain and levels rise further in response to fetal stress. The placenta contributes steroid precursors that help maintain these high neurosteroid levels. This placenta-fetal brain interaction comprises an internal mechanism that protects the fetal brain from adverse events during pregnancy. At birth, however, there is a dramatic decline in neurosteroid concentrations in the brain after the loss of the placental precursor supply. The fall in concentrations is even greater in animals that are born growth restricted. This suggests that newborns, particularly those from compromised pregnancies, are at increased risk of brain damage due to low neurosteroid levels. We believe that certain commonly used steroid therapies may also lower steroid levels in the brain and result in increased vulnerability to brain damage during birth or in the early neonatal period. Alternatively, we propose that replacement of neurosteroid precursors in the newborn may raise brain neurosteroid levels and protect against brain damage. In the proposed studies we will evaluate treatments that can raise the concentration of steroids and determine the best strategy for reducing brain injury following complications during pregnancy, at birth and during the early newborn period. This work will determine the best therapeutic approaches for maximising neurosteroid-induced brain protection and for reducing the risk of brain damage.Read moreRead less
Neuroactive Steroids In The Developing Brain: Potential For Preventing Perinatal Brain Damage
Funder
National Health and Medical Research Council
Funding Amount
$481,500.00
Summary
Complications during pregnancy, birth asphyxia or premature birth can lead to serious neurological impairment in the newborn. Despite excellent neonatal care many of these babies go on to have serious handicaps. Neuroactive steroids are a group of neuromodulators that are derived from the hormone progesterone. These steroids fall into two groups, those that appear to protect brain cells from damage caused by an inadequate supply of oxygen and those that may increase cell death. We have shown tha ....Complications during pregnancy, birth asphyxia or premature birth can lead to serious neurological impairment in the newborn. Despite excellent neonatal care many of these babies go on to have serious handicaps. Neuroactive steroids are a group of neuromodulators that are derived from the hormone progesterone. These steroids fall into two groups, those that appear to protect brain cells from damage caused by an inadequate supply of oxygen and those that may increase cell death. We have shown that protective neuroactive steroids are present in very large amounts in the fetal brain. Steroids produced by the placenta are converted to these neuroactive products by enzymes in the brain leading to the high levels that are seen during fetal life. Certain adverse conditions during pregnancy as well as preterm birth may cause marked changes in the balance of steroids that could increase susceptibility to brain injury. We have found that areas of the brain, where damage most often occurs, normally contain the highest amount of protective steroids, but only in late pregnancy. This suggests that disturbances that lower steroid production in these areas could contribute to the death of cells, particularly in mid-pregnancy and after premature birth. In the proposed studies, we will examine whether a toxic balance of steroids develops following adverse events in pregnancy as well as the areas of the brain where this is most pronounced. We will examine the changes in the expression of enzymes that can potentially cause the accumulation of protective steroids in the brain. We will then examine treatments that can raise the concentration of steroids and determine which combination of steroids best reduces cell death and brain injury following complications during pregnancy. The findings of this work will indicate the best therapeutic approach that may be adopted to modify the concentration of certain steroids so as to reduce the risk of brain damage in the fetus and neonate.Read moreRead less
Can Skin Infection With Group A Streptococcus Cause Acute Rheumatic Fever?
Funder
National Health and Medical Research Council
Funding Amount
$459,450.00
Summary
It is traditionally taught that the cause of acute rheumatic fever (ARF) is always infection of the throat with the bacterium group A streptococcus (GAS). However, in Aboriginal communities of the Top End of the Northern Territory the incidence of ARF is the highest reported in the world, yet GAS is uncommonly isolated from the throat. There is further information to suggest that GAS skin sores may underlie many cases of ARF. If this were proven, it would completely alter the traditional view of ....It is traditionally taught that the cause of acute rheumatic fever (ARF) is always infection of the throat with the bacterium group A streptococcus (GAS). However, in Aboriginal communities of the Top End of the Northern Territory the incidence of ARF is the highest reported in the world, yet GAS is uncommonly isolated from the throat. There is further information to suggest that GAS skin sores may underlie many cases of ARF. If this were proven, it would completely alter the traditional view of the cause of ARF, and have important implications for prevention of ARF around the world. Presently, these approaches focus on diagnosing and treating sore throat, but no country has proven that such a program can be successful in substantially reducing new cases of ARF. If it was known that skin infection could lead to ARF, then countries (including Australia) could emphasise the importance of skin health programs. A further benefit of this knowledge would be to influence GAS vaccine development, which presently is largely focused on the prevention of sore throat. A different possibility has recently been raised - that the cause of ARF may not always be GAS, but instead that the related bacteria GCS and GGS may have the potential to cause this disease. Proof of this hypothesis would even more dramatically alter our understanding of disease causation, prevention, and vaccine development. We propose to determine the cause of ARF in Aboriginal communities by regularly swabbing families of people with a history of ARF, and using genetic fingerprinting of the bacteria from the skin and throat swabs. When cases of ARF occur, we will be able to determine the site and type of infection that precipitated the attack. We will conduct a related study in more communities, in which we will swab family members of people with ARF and of control families (without ARF) to determine the bacteria most commonly isolated from ARF families.Read moreRead less
Does Caffeine Affect The Development Of The Very Immature Brain: Dose Response Relationship?
Funder
National Health and Medical Research Council
Funding Amount
$668,386.00
Summary
Premature birth is a major health problem worldwide. Preterm babies often develop apnoea of prematurity (AOP), which is commonly treated with caffeine. Trials indicate that preterm babies treated with low dose caffeine have less neurodevelopmental disabilities at 18 months. Higher doses of caffeine are often needed to reduce AOP but the risk of this is unknown. We will study the short and long-term effects of increasing doses of caffeine on the developing brain in a long-gestation species.
Contribution Of Disturbed Blood Flow And Cerebral Metabolism To White Matter Damage In The Perinatal Brain
Funder
National Health and Medical Research Council
Funding Amount
$369,375.00
Summary
It has been known for some time that the white matter regions of the developing brain are particularly vulnerable to damage. These regions are deep in the brain near the ventricles, and are rich in myelin sheaths wrapped around the nerve fibres running from cell-rich areas in the outer layers of the brain to other regions, and down into the spinal cord. Damage to white matter usually leads to behavioural, learning and motor problems in the newborn infant - in its severest form, seen as cerebral ....It has been known for some time that the white matter regions of the developing brain are particularly vulnerable to damage. These regions are deep in the brain near the ventricles, and are rich in myelin sheaths wrapped around the nerve fibres running from cell-rich areas in the outer layers of the brain to other regions, and down into the spinal cord. Damage to white matter usually leads to behavioural, learning and motor problems in the newborn infant - in its severest form, seen as cerebral palsy. Such outcomes are often associated with the presence of asphyxia and infection during pregnancy, leading to the belief that the damage first arises while the baby is still in utero. In this application we suggest that asphyxia and-or infection during pregnancy cause prolonged disturbances in the regulation of blood flow and integrity of the blood-brain barrier in the developing brain, together with changes in metabolism that result in accumulation of prostaglandins and the toxic hydroxyl radical, leading irreversibly to cell death. If this series of events proves to be true, we have suggested and will test several protocols for protecting the fetal brain, which should be readily translatable to clinical practice.Read moreRead less
Functional Contribution Of Fetal Microchimeric Cells In Transgenic Models Of Maternal Tissue Repair In And After Pregnancy
Funder
National Health and Medical Research Council
Funding Amount
$542,462.00
Summary
Fetal stem cells cross into the mother during pregnancy and persist lifelong in her tissues. To determine whether helpful or harmful, we will study how these cells contribute to healing both after acute injury and in chronic genetic models like brittle-bone disease and muscular dystrophy. This research will inform long-term consequences of pregnancy, important for women's health and longevity, and help develop a promising form of stem cell therapy.
Infectious And Lifestyle Determinants Of Non-melanoma Skin Cancer.
Funder
National Health and Medical Research Council
Funding Amount
$983,711.00
Summary
Basal and squamous cell skin cancers are the leading cancers in Australia, with about 2% of the population developing them each year. As well as sun exposure, a number of other factors have been thought to effect these cancers. This study will examine if factors such as smoking, alcohol consumption and infection with certain skin related human papillomaviruses also increase their risk. Even a small effect may make a big difference when it comes to preventing these common cancers.
Role Of Brm In Skin Tumour Progression From Benign To Malignant
Funder
National Health and Medical Research Council
Funding Amount
$457,267.00
Summary
Australia has the highest incidence of skin cancer in the world. Skin cancer is 3 times as common as all other cancers combined and continues to increase in incidence, particularly in the aging population. Skin cancer is caused by exposure to the ultraviolet radiation found in sunlight. Ultraviolet radiation causes the appearance of solar keratosis, or sunspots, benign lesions that are not particularly dangerous to human health. Some of these develop into malignant squamous cell carcinomas that ....Australia has the highest incidence of skin cancer in the world. Skin cancer is 3 times as common as all other cancers combined and continues to increase in incidence, particularly in the aging population. Skin cancer is caused by exposure to the ultraviolet radiation found in sunlight. Ultraviolet radiation causes the appearance of solar keratosis, or sunspots, benign lesions that are not particularly dangerous to human health. Some of these develop into malignant squamous cell carcinomas that can spread to other tissues and are potentially fatal. Little is known about the biological mechanisms involved in solar keratosis development into squamous cell carcinomas. We have identified the gene brm as being involved in this process. It has not previously been recognised that this gene is important for skin cancer development and therefore our preliminary studies have identified a potential new target. We will study the role of this gene in ultraviolet radiation induced skin carcinogenesis, determine whether it is mutated by ultraviolet radiation in human skin cancer, and what role in plays in some key biological processes in skin cancer development. This study will expand our understanding of malignant conversion during human skin carcinogenesis, the most prevalent human cancer in Australia.Read moreRead less
Cell Type Specific Biologic Responses To HIV Infection
Funder
National Health and Medical Research Council
Funding Amount
$636,242.00
Summary
The way in which HIV alters the internal environment of its target cells to facilitate its growth will be examined. These changes enhance its ability to gain a toehold in the human body after entering the genital tract and its persistence for life in the brain and elsewhere in the body.
Insulin resistance (the inability of ordinarily insulin-sensitive tissues such as muscle and adipose tissue to respond to insulin) contributes to a number of diseases including diabetes and obesity. A key metabolic step in these tissues is the uptake of glucose from the blood stream. This step is accelerated by insulin thus allowing efficient clearance of glucose from the bloodstream after a meal. Our laboratory has played a major role in showing that insulin regulates glucose uptake into muscle ....Insulin resistance (the inability of ordinarily insulin-sensitive tissues such as muscle and adipose tissue to respond to insulin) contributes to a number of diseases including diabetes and obesity. A key metabolic step in these tissues is the uptake of glucose from the blood stream. This step is accelerated by insulin thus allowing efficient clearance of glucose from the bloodstream after a meal. Our laboratory has played a major role in showing that insulin regulates glucose uptake into muscle and adipose tissue by stimulating the movement of a glucose transport protein from inside the cell to the cell surface (see http:--www.imb.uq.edu.au-groups-james-glut4 for an animated description of this process). The purpose of this proposal is to dissect the molecular mechanisms by which this glucose transporter can be held inside the cell in the absence of insulin and then allowed to be released from this site moving to the surface in the presence of insulin. Our studies over the past 5 years have brought us much closer to understanding this process in detail. The identification of the molecules responsible for this regulatory step will not only aid our understanding of this process but it will also provide a valuable target for development of therapeutic agents that can be used to combat insulin resistance.Read moreRead less