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
Role Of IGF Binding Protein-3 (IGFBP-3) And IGFBP-5 As Modulators Of Nuclear Hormone Signalling
Funder
National Health and Medical Research Council
Funding Amount
$465,750.00
Summary
The insulin-like growth factors are small proteins involved in the growth of most tissues. Their actions are regulated by binding to larger proteins (known as IGFBPs) in the bloodstream and outside the cell. However, some IGFBPs are also found inside cells, where they seem to carry out other functions. We believe that two of these binding proteins, IGFBP-3 and IGFBP-5, change the way cells respond to vitamin A and vitamin D. These two vitamins are important in cell growth and in the way certain ....The insulin-like growth factors are small proteins involved in the growth of most tissues. Their actions are regulated by binding to larger proteins (known as IGFBPs) in the bloodstream and outside the cell. However, some IGFBPs are also found inside cells, where they seem to carry out other functions. We believe that two of these binding proteins, IGFBP-3 and IGFBP-5, change the way cells respond to vitamin A and vitamin D. These two vitamins are important in cell growth and in the way certain cells perform specialised functions. In test-tube experiments, IGFBP-3 and IGFBP-5 interact directly with the receptors that regulate the effects of these hormones. If the same thing happens inside the cell, IGFBP-3 and IGFBP-5 could change the way these receptors respond to signals from outside the cell. We will investigate what effect these IGFBPs have in living cells and in whole animals and how this may relate to human disease. If we are able to understand how IGFBP-3 and IGFBP-5 affect the way cells respond to vitamin A and D, then we may be able to develop new ways to treat certain human diseases.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
Molecular Regulation Of Metabolism And Body Composition By Ski Via Crosstalk With Nuclear Hormone Receptor Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$558,441.00
Summary
Obesity is a common and burdensome health problem in the community which leads to diabetes and heart disease. A number of factors, including hormones play important roles in determing risk of obesity. This study proposes to investigate whether the Ski gene which is a regulatory factor for many hormones affects metabolism in transgenic mouse models of altered Ski function. The proposed studies may identify Ski as a target for therapy for obesity and improvement in sketal muscle metabolism.
Signalling Networks As Targets For Antibody Therapy In Glioma.
Funder
National Health and Medical Research Council
Funding Amount
$526,683.00
Summary
Antibodies are a major component of the bodies immune system that bind (i.e. stick) to foreign substances such as viruses. Once bound, these antibodies can activate other parts of the immune system, which help destroy the foreign substance. Analogous to the situation above, a number of institutions are testing antibodies that bind to cancer cells, in order to determine if they are able to destroy these cells. It is also possible to generate antibodies that bind to receptors on the surface of can ....Antibodies are a major component of the bodies immune system that bind (i.e. stick) to foreign substances such as viruses. Once bound, these antibodies can activate other parts of the immune system, which help destroy the foreign substance. Analogous to the situation above, a number of institutions are testing antibodies that bind to cancer cells, in order to determine if they are able to destroy these cells. It is also possible to generate antibodies that bind to receptors on the surface of cancer cells and block their function. If you target a receptor critical to the growth or survival of a cancer cell in this way, then swtiching-off this signal may inhibit tumor growth. In this proposal we plan to test a panel antibodies that recognize receptors important to the growth of brain cancer. Two of these antibodies have been generated and the other two will be made as part of this proposal. A key aspect of this proposal will be testing these antibodies in combination to determine how many receptors need to be targeted in order to get complete tumor regressions in animal models. Overall this work will help us identify new therapeutic strategies for the treatment of brain cancer. Finally, we will also analyze the way different receptors interact together in brain cancer cells.Read moreRead less