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
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
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.
Perinatal Stress Leads To Neurosteroid Deficits And Adverse Behavioural Outcomes
Funder
National Health and Medical Research Council
Funding Amount
$1,198,042.00
Summary
This grant will examine the effect of psychosocial stress experienced after birth on the production and regulation of steroid hormones in the brain of newborn animals. The work will investigate how stress changes the levels these brain steroids and sensitivity to them and if these effects are remain into adulthood. The studies will then determine if these changes lead to adolescent behaviour disorders. The effectiveness of steroid therapies in treating these disorders will also be determined.
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
Genetic mechanisms of metabolic control and thermal sensing during thermoregulation. This research will significantly advance understanding of how animals can respond to climate change, and the results will benefit wildlife management processes. The proposed research will lead to collaboration with Prof. Ken Storey an ISI highly cited author and expert in microarray analysis. The cDNA microarray for Crocodylus porosus which I will construct in the proposed research will be a valuable resource ....Genetic mechanisms of metabolic control and thermal sensing during thermoregulation. This research will significantly advance understanding of how animals can respond to climate change, and the results will benefit wildlife management processes. The proposed research will lead to collaboration with Prof. Ken Storey an ISI highly cited author and expert in microarray analysis. The cDNA microarray for Crocodylus porosus which I will construct in the proposed research will be a valuable resource for Australia by increasing collaborations, and it will help find the cause of problems prevalent in the crocodile industry such as runt animals that significantly decrease production efficiency.Read moreRead less
The role of intracellular calcium in fibre-type specific gene expression in skeletal muscle. Muscles contain different fibre types whose composition can be changed by activity. The aim of this proposal is to identify the intracellular mechanisms which control fibre type. Our hypothesis is that different patterns of intracellular calcium determine the pattern of gene expression which determines fibre type. Understanding how gene expression is regulated is a central issue in biology.
The role of intracellular calcium stores in cardiac pacemaking. The spontaneous firing of pacemaker cells is central to regulation of the cardiovascular system particularly during exercise. The discovery that pacemaker cell function is modulated in part by calcium ions will change our understanding of the changes in heart rate during exercise and in diseases which affect the pacemaker cells. Better understanding of the way in which spontaneous activity of these cells is regulated is the key to ....The role of intracellular calcium stores in cardiac pacemaking. The spontaneous firing of pacemaker cells is central to regulation of the cardiovascular system particularly during exercise. The discovery that pacemaker cell function is modulated in part by calcium ions will change our understanding of the changes in heart rate during exercise and in diseases which affect the pacemaker cells. Better understanding of the way in which spontaneous activity of these cells is regulated is the key to controlling or modifying their function.Read moreRead less
Intracellular calcium in intact muscle during fatigue and stretch-induced damage. Confocal microscopes can investigate intact tissues during normal function. We will develop and apply this novel approach to muscle. We expect this new approach to become a fundamental new tool for exploring muscle function under near normal conditions. Muscle pain and weakness are common disabilities in humans and we expect this new approach to provide insights into the causes and treatment of these common cond ....Intracellular calcium in intact muscle during fatigue and stretch-induced damage. Confocal microscopes can investigate intact tissues during normal function. We will develop and apply this novel approach to muscle. We expect this new approach to become a fundamental new tool for exploring muscle function under near normal conditions. Muscle pain and weakness are common disabilities in humans and we expect this new approach to provide insights into the causes and treatment of these common conditions.Read moreRead less
The Immunoregulatory Role of the Endogenous Cannabinoid Anandamide. Anandamides are naturally occurring fatty acids that act at the cannabinoid receptor expressed in the brain and periphery. A new proposal by our research group challenges traditional models of the disease process by suggesting that the anandamide system is an important imunoregulatory system that can be targeted by invading pathogens. We propose that disruption to the anandamide system, by bacteria or viruses acting at the rece ....The Immunoregulatory Role of the Endogenous Cannabinoid Anandamide. Anandamides are naturally occurring fatty acids that act at the cannabinoid receptor expressed in the brain and periphery. A new proposal by our research group challenges traditional models of the disease process by suggesting that the anandamide system is an important imunoregulatory system that can be targeted by invading pathogens. We propose that disruption to the anandamide system, by bacteria or viruses acting at the receptor to block immunological responses, contributes to chronic illness states. At this point we have good evidence that anandamides are immunoregulators, however, we have very little knowledge of their precise physiological role. The aim of this research is to begin to characterise the immunoregulatory role of the anandamide system. This project will provide a comprehensive understanding of this endogenous control system, the immunological properties of which have not previously been described. The outcome of this research may lead to the identification of new avenues for the development of pharmaceutical interventions that can target this system.Read moreRead less