Our mission is to establish a new and innovative approach to the prevention and treatment of heart disease and stroke,
The Thrombosis Group is internationally renowned for its innovative research into blood clot formation and factors, which can exacerbate development of pathological clots, leading to heart attacks and stroke. Our findings go a long way to explaining why the drugs we currently administer to patients with cardiovascular disease – which target the blood-borne chemicals – don’t always work.
What impact will this research have?
Atherothrombosis is a major healthcare problem in Australia, affecting more than 50 per cent of the adult population. We’re hoping to develop innovative approaches to reduce the risk of blood clot in patients and ultimately save lives.
Current projects and goals
Research undertaken in our laboratory is focussed on determining the mechanisms underlying clot formation in healthy individuals; using this knowledge to better understand the mechanisms leading to platelet hyperactivity and pathological blood clot formation;and ultimately development of safer and more effective therapies to treat cardiovasuclar diseases including heart attack, stroke, diabetes and the metabolic syndrome.
“Bad Blood”: Unravelling the link between gut ischemia and remote organ injury
Ischaemic injury to vital organs is common in critically ill patients, producing deleterious effects on other organ systems. This is particularly common in the gut, with intestinal hypoperfusion inducing systemic inflammation and multiorgan organ dysfunction syndrome. In addition to promoting inflammation, prolonged ischemic injury to the intestines can also lead to the development of a systemic thrombotic response (pathological formation of blood clots), which is particularly common in the lung, and leads to a very poor prognosis (>90% mortality). We have identified a new mechanism of pathological blood clotting (thrombosis) and vascular occlusion that is triggered by dying platelets in the intestinal microvasculature. Our ultimate aim is to identify new therapeutic targets to improve microvascular perfusion and reduce inflammation and organ injury, which may represent an innovative approach to reduce remote organ injury in critically ill patients. This project will involve the use of animal models of ischaemia reperfusion, confocal microscopy, gut and lung histology, and other in vitro cell biology and biochemical approaches.
Solving a sticky clotting problem in diabetes
The leading cause of death in diabetes is cardiovascular disease, with up to 70% of deaths relating to the development of blood clots supplying the heart (heart attack) or brain (ischemic stroke). Diabetic individuals are more prone to develop blood clots, and these clots are more resistant to standard anticlotting therapies. Our laboratory has discovered a new biomechanical clotting mechanism severely affected by diabetes that is resistant to the beneficial effects of commonly used antithrombotic agents. Studies ongoing in our laboratory aim to identify how high blood sugar levels (hyperglycaemia) can enhance this new clotting mechanism. To achieve this, we are using Biomembrane force probe (‘BFP’) technology, which allows us to study how a single platelet senses mechanical cues at the molecular scale. We will also examine the role chronic oxidative stress plays in amplifying blood clotting in diabetes, and the mechanisms by which oxidative stress may modify platelet receptors to enhance adhesion. These studies may identify novel targets with which to treat thrombosis associated with diabetes. This project will involve the use of in vivo animal models, Biomembrane force probe (‘BFP’) technology, biochemistry and mass spectoscopy.
New approaches to the treatment of ischaemic stroke
The development of a blood clot in the cerebral circulation (ischaemic stroke) is the third most common cause of death and the most common cause of adult disability globally. The central goal of stroke therapy is the prompt reperfusion of occluded blood vessels to minimise tissue death. The delivery of fibrinolytic agents modelled on tissue-type plasminogen activator (t-PA) is the only clinically approved means available to stroke patients. Despite this, the use of t-PA is associated with significant side effects, limiting its widespread use. We are working on a novel approach to improve upon existing stroke therapies, making them safer and more effective. Ongoing studies using a novel mouse model of thrombolysis (iCAT) developed in our lab will determine whether cerebral damage and cognitive impairment associated with stroke are reduced using this approach. This project will involve the use of animal models of stroke, behavioural analysis, laser speckle contrast and Laser Doppler Flow imaging, histology, and cell biology approaches.
Investigating blood flow reductions in the brain after stroke
Acute ischemic stroke is a leading cause of death and disability worldwide. It is caused by the blockage of a major artery that supplies the brain. Injury occurs as a consequence of the reductions in blood flow and the longer the brain stays hypoperfused, the greater the damage inflicted. It has long been known that quickly restoring blood flow to the brain will limit the progression of cell death and improve patient outcome after stroke. However, there is evolving evidence that reopening the blocked artery does not always restore blood flow in the small vessels of the brain and correlates with worse prognosis for stroke patients. The causes of the continued hypoperfusion is poorly understood. Identifying the causes of these blood flow reductions despite large vessel reopening will provide targets for potential new stroke therapies. This project will involve the use of animal models of stroke, behavioural analysis, laser speckle contrast and Laser Doppler Flow imaging, histology, and cell biology approaches.
Platelet death as an important regulator of blood clot formation
The generation of a fibrin blood clot is driven by coagulation factors present in the plasma. These factors assemble on negatively charged endothelial surfaces, such as phosphatidylserine (PS), to facilitate thrombin generation and promote blood clot formation. Platelets are also capable of exposing PS on their outer membrane and promoting localised thrombin generation – a process referred to as platelet ‘procoagulant’ function. All currently employed anticoagulant agents indiscriminately inhibit blood clotting reactions at the injured vessel wall and throughout the body of a developing blood clot, resulting in increased bleeding risk for patients receiving these medications.
Our laboratory has demonstrated that procoagulant platelets are dying cells, undergoing a cell death process akin to necrosis, leading to PS exposure and thrombin generation. We have also found that the adaptor protein 14-3-3z plays an important role in regulating platelet death necessary for blood clot growth and stability. We aim to determine whether therapeutic targeting of this pathway, either alone, or in combination with necrotic cell death pathways, represents a safe and effective way of reducing thrombin generation in vivo without increasing bleeding risk.
This project will involve an array of in vitro biochemistry and platelet biology assays, along with in vivo models of thrombosis and confocal imaging techniques.