Actions Of The Polyphenol Epigallocatechin 3-gallate On Insulin Sensitivity
Funder
National Health and Medical Research Council
Funding Amount
$409,746.00
Summary
This project will determine whether the bioactive compound in green tea (called EGCG) can reduce insulin resistance by enhancing the ability of insulin to open very small blood vessels (called capillaries) in muscle. Opening more capillaries will help glucose to be stored in muscle, thus alleviating insulin resistance. Findings from these studies may have important impact on the management of insulin resistance and type 2 diabetes.
Mechanisms Linking Insulin-mediated Muscle Capillary Recruitment And Glucose Uptake
Funder
National Health and Medical Research Council
Funding Amount
$315,990.00
Summary
A number of studies over recent years including our own have suggested that insulin acts in normal humans and animals to improve blood supply to muscle and that a contributing factor to Type 2 diabetes is an impaired ability of insulin to achieve this effect. Our key contribution to this field is the finding that insulin acts to alter blood flow in muscle to improve access for itself and nutrients such as glucose. This discovery of blood flow redistribution in muscle was made possible by newly d ....A number of studies over recent years including our own have suggested that insulin acts in normal humans and animals to improve blood supply to muscle and that a contributing factor to Type 2 diabetes is an impaired ability of insulin to achieve this effect. Our key contribution to this field is the finding that insulin acts to alter blood flow in muscle to improve access for itself and nutrients such as glucose. This discovery of blood flow redistribution in muscle was made possible by newly developed in-house methods. Using these methods we now wish to explore (a) the mechanism by which insulin mediates this effect and (b) when this effect of insulin to improve muscle blood flow is impaired in diabetes, how it might be recovered. We expect to find that insulin-mediated capillary recruitment in muscle results from a signal substance released from muscle that permeates nearby tissue reacting with the blood vessels to improve blood flow. It is also expected that new therapeutic approaches for enhancing insulin action in muscle and targeted at the blood vessels will be identified.Read moreRead less
Cyclic GMP Phosphodiesterase Inhibitors And Facilitation Of Insulin-mediated Capillary Recruitment In Muscle
Funder
National Health and Medical Research Council
Funding Amount
$220,500.00
Summary
It would now seem clear that insulin has a major stimulatory effect on blood flow within muscle to improve access for itself as well as nutrients such as glucose. When this haemodynamic effect of insulin is impaired insulin resistance in terms of glucose uptake by muscle results and there is the potential for type 2 diabetes to develop. Our key contribution has been the development of new techniques to make this observation possible and it would be fair to say that we are the world leaders in th ....It would now seem clear that insulin has a major stimulatory effect on blood flow within muscle to improve access for itself as well as nutrients such as glucose. When this haemodynamic effect of insulin is impaired insulin resistance in terms of glucose uptake by muscle results and there is the potential for type 2 diabetes to develop. Our key contribution has been the development of new techniques to make this observation possible and it would be fair to say that we are the world leaders in this field because of these techniques. Using these methods we now wish to develop new drugs for treating type 2 diabetes based on improving muscle capillary blood flow. The approach we will use is similar to that used previously by others for the treatment of erectile dysfunction with drugs targeted at a particular enzyme controlling the metabolism of a substance (cyclic GMP) which in turn regulates blood flow to the corpus cavernosum. In our case, the drugs will be targeted at another specific isoform of the same enzyme, cyclic GMP phosphodiesterase, located at control points in the skeletal muscle microvasculature. We expect to find that insulin-mediated capillary recruitment in muscle will be enhanced by such drugs. As a consequence, insulin resistance in muscle will be lessened.Read moreRead less
Sympathetic Control Of Cutaneous Blood Flow And Blood Pressure In Human Spinal Cord Injury
Funder
National Health and Medical Research Council
Funding Amount
$242,002.00
Summary
While spinal cord injury can cause devastating changes in the nervous system paralysis and loss of sensation relatively little is known about changes to the sympathetic nervous system. The sympathetic nervous system is intimately involved in the ongoing control of blood pressure, blood flow and temperature control. Loss of sympathetic control can occur following spinal cord injury. Interruption of descending pathways can result in partial or complete loss of sympathetic outflow from the thoracol ....While spinal cord injury can cause devastating changes in the nervous system paralysis and loss of sensation relatively little is known about changes to the sympathetic nervous system. The sympathetic nervous system is intimately involved in the ongoing control of blood pressure, blood flow and temperature control. Loss of sympathetic control can occur following spinal cord injury. Interruption of descending pathways can result in partial or complete loss of sympathetic outflow from the thoracolumbar segments. Complete decentralization can result in autonomic dysreflexia (autonomic hyperreflexia), in which sensory stimuli originating below the lesion evoke a reflex increase in sympathetic drive to the blood vessels, causing them to constrict. Because of this, blood pressure may rise suddenly and remain at such high levels that stroke and (occassionally) cardiac arrest may occur. This phenomenon, autonomic dysreflexia, is considered a medical emergency. The typical subjective signs of autonomic dysreflexia include a throbbing headache, tingling in the head or nasal congestion; sweating and flushing above the lesion are clinical signs that prompt medical staff to measure blood pressure and to locate the source of sensory irritation (usually a distended bladder or impacted colon, sometimes a pressure sore or ingrown toenail). Commonly, however, subclinical episodes go undetected, and this phenomenon of silent dysreflexia is of increasing concern. This project will develop means of assessing the integrity and state of the sympathetic nervous system below a lesion in patients with spinal cord injury and characterize the firing properties of reflexly activated sympathetic neurones.Read moreRead less