Early Events In Arteriolar Remodeling: Adaptation To Prolonged Vasoconstriction
Funder
National Health and Medical Research Council
Funding Amount
$415,750.00
Summary
Small arteries, while acutely responding to their environment with changes in diameter to regulate local blood flow and pressure, also undergo structural adaptation or remodelling. These events occur over a range of time-frames and involve both non-genetically and genetically regulated events. Thus a contractile event, while initially decreasing vessel diameter, also activates longer time frame processes which can span from rearrangment of cellular junctions-contacts to overt structural changes ....Small arteries, while acutely responding to their environment with changes in diameter to regulate local blood flow and pressure, also undergo structural adaptation or remodelling. These events occur over a range of time-frames and involve both non-genetically and genetically regulated events. Thus a contractile event, while initially decreasing vessel diameter, also activates longer time frame processes which can span from rearrangment of cellular junctions-contacts to overt structural changes within the vessel wall (for example thickening of the muscle layer). These adaptive processes may enable the forces of contraction to be maintained without continued energy expenditure and damage to the vessel per se. However, they can also contribute to long-term alterations in the control of blood pressure and perhaps contribute to states of hypertension as well as other common vascular diseases. For these studies we will use arterioles, isolated by microsurgical techniques, together with sophisticated computer and video-based approaches. These techniques allow arterioles to be studied under controlled conditions and relevant biochemical measurements performed. We will also use a cell model where cultured cells will be studied after defined periods of mechanical stimulation (for example stretch). Cells will be probed using a novel microscopic technique (atomic force microscopy) which enables the cell membrane to be studied with respect to changes in composition as well as physical characteristics (for example stiffness). The studies are relevant to our understanding of the normal adaptive processes occurring within blood vessels to control blood flow and pressure. The studies are also of direct relevance to our understanding of common vascular disease states including hypertension, complications of diabetes and chronic inflammatory disorders.Read moreRead less
Pathogenesis Of Vascular Shock And Platelet Dysfunction In Sepsis: The Role Of Calcium Desensitization, Statins And Cortisol.
Funder
National Health and Medical Research Council
Funding Amount
$89,778.00
Summary
Severe infections are characterised by a profound drop in blood pressure, which starve vital organs of oxygen and nutrients, this �septic shock� can lead to organ failure and death. We aim to identify dysfunction of the molecular signals in blood vessels, which leads to the failure of these vessels to maintain adequate blood pressure. Understanding the mechanisms regulating blood pressure during septic shock will enable us to develop therapies to support the circulation and reduce the significan ....Severe infections are characterised by a profound drop in blood pressure, which starve vital organs of oxygen and nutrients, this �septic shock� can lead to organ failure and death. We aim to identify dysfunction of the molecular signals in blood vessels, which leads to the failure of these vessels to maintain adequate blood pressure. Understanding the mechanisms regulating blood pressure during septic shock will enable us to develop therapies to support the circulation and reduce the significant death toll from life threatening sepsis.Read moreRead less
Origin Of Cells In The 'artificial' Artery Grown In The Peritoneal Cavity
Funder
National Health and Medical Research Council
Funding Amount
$489,000.00
Summary
Implantation of a foreign object (such as a sterile, flexible plastic tube) into the abdominal cavity of animals induces cells floating in the peritoneal fluid to form a capsule around the object. Over the next 2-3 weeks, the cells differentiate into fibroblasts then myofibroblasts. When this capsule of living tissue (in the appropriate moulded shape) is subsequently grafted into smooth muscle-rich organs such as artery, bladder, uterus or vas deferens to replace excised segments, it gains the s ....Implantation of a foreign object (such as a sterile, flexible plastic tube) into the abdominal cavity of animals induces cells floating in the peritoneal fluid to form a capsule around the object. Over the next 2-3 weeks, the cells differentiate into fibroblasts then myofibroblasts. When this capsule of living tissue (in the appropriate moulded shape) is subsequently grafted into smooth muscle-rich organs such as artery, bladder, uterus or vas deferens to replace excised segments, it gains the structure of the surrounding tissue and the myofibroblasts differentiate further into functional smooth muscle. This raises the question: what is the origin of the cells of the capsule? Our previous studies suggested that monocyte-macrophages stimulated to enter the abdominal cavity in response to the sterile foreign body might be the source of the cells. In the current study we will use transgenic (c-fms EGFP and c-fms Cre Z-AP) mice in which cells of monocyte-macrophage lineage are genetically labelled. These cells can be clearly distinguished from all other cells of the body, and analysis of capsules formed around foreign bodies will give us a definitive answer. We will using micro-array analysis, determine which growth factors-cytokines are important in regulating differentiation of the cells, and the role of physical factors (eg pulsatile stretching). Finally, we will determine whether these cells stimulated to enter the abdominal cavity are capable of differentiating along alternative pathways, such as cardiac muscle or liver cells. Knowledge gained will further the use of the abdominal cavity as a bioreactor in which to engineer tissues for organ replacement therapies. Identification of the mechanisms regulating the (trans)differentiation and biology of the cells may also assist in wound repair strategies to prevent pathologies caused by excessive myofibroblast accumulation and fibrosis.Read moreRead less