Molecular Mechanisms Linking Proteinuria And Sodium Retention
Funder
National Health and Medical Research Council
Funding Amount
$211,527.00
Summary
The clinical association between protein loss in the urine and retention of salt, resulting in high blood pressure and progressive decline in kidney function, is well known. Under normal conditions, the kidneys filter 180 litres of water and reabsorb 1.7 kg of salt per day, a function which is principally performed by the kidney tubules in the kidney. Similarly the kidney tubule cells reabsorb and break down up to 3 grams of albumin per day. In the past, it has been considered that excessive pro ....The clinical association between protein loss in the urine and retention of salt, resulting in high blood pressure and progressive decline in kidney function, is well known. Under normal conditions, the kidneys filter 180 litres of water and reabsorb 1.7 kg of salt per day, a function which is principally performed by the kidney tubules in the kidney. Similarly the kidney tubule cells reabsorb and break down up to 3 grams of albumin per day. In the past, it has been considered that excessive protein loss in the urine is primarily due to problems in the filtering units of the kidneys, rather than due to abnormalities in the reabsorption of protein in the kidney tubules. However, we consider that common abnormalities in the processes within the kidney tubules that regulate both the reabsorption of salt and the excretion of acid may result in concomitant high blood pressure and increased protein loss in the kidney. Thus the overall aim of the project is to investigate the interrelationship between protein reabsorption and catabolism and Na+ reabsorption in the human kidney tubule. The project uses the combined methods of cultured human kidney tubules, biochemical and molecular biology techniques which are unavailable in other laboratories in Australia (and internationally). This project will comprehensively characterise the mechanisms of protein uptake and salt reabsorption in human kidney tubule cells when exposed to both normal and high concentrations of protein. The exact nature of the interaction of protein uptake with salt reabsorption and hence high blood pressure will be determined. As both hypertension and persistent proteinuria are the most important predictors of tubulointerstitial pathology and progressive decline in renal function in almost all renal disease, the understanding of the precise interaction between these two factors is essential in the design of renoprotective therapies.Read moreRead less
Two-photon Microscopy Of Albumin Handling By The Intact Kidney
Funder
National Health and Medical Research Council
Funding Amount
$346,602.00
Summary
The clinical association between protein loss in the urine and retention of salt, resulting in high blood pressure and progressive decline in kidney function, is well known. Under normal conditions, the kidneys filter 180 litres of water and reabsorb 1.7 kg of salt per day, a function which is principally performed by the kidney tubules in the kidney. Similarly the kidney tubule cells reabsorb and break down up to 3 grams of albumin per day. In the past, it has been considered that excessive pro ....The clinical association between protein loss in the urine and retention of salt, resulting in high blood pressure and progressive decline in kidney function, is well known. Under normal conditions, the kidneys filter 180 litres of water and reabsorb 1.7 kg of salt per day, a function which is principally performed by the kidney tubules in the kidney. Similarly the kidney tubule cells reabsorb and break down up to 3 grams of albumin per day. In the past, it has been considered that excessive protein loss in the urine is primarily due to problems in the filtering units of the kidneys, rather than due to abnormalities in the reabsorption of protein in the kidney tubules. However, we consider that common abnormalities in the processes within the kidney tubules that regulate both the reabsorption of salt and the excretion of acid may result in concomitant high blood pressure and increased protein loss in the kidney. Thus the overall aim of the project is to investigate the mechanisms by which the complex responsible for protein uptake determines the interrelationship between protein reabsorption and catabolism and the ion transporting proteins in the membrane of the proximal tubule. This project will use cutting-edge microscopic imaging technology to investigate the mechanisms of protein uptake in the intact kidney. This information will be integrated with data obtained from our molecular physiology experiments to define how the kidney handles protein. As persistent proteinuria is the most important predictor of tubulointerstitial pathology and progressive decline in renal function in almost all renal disease, the understanding of the precise mechanism by which this occurs is essential in the design of renoprotective therapies.Read moreRead less
Physiological Function Of Nedd4-2 In Regulating The Epithelial Sodium Channel And Cystic Fibrosis Transmembrane Conductance Regulator
Funder
National Health and Medical Research Council
Funding Amount
$949,572.00
Summary
Optimal transport of sodium and chloride ions is essential for the maintenance of electrolyte balance, blood volume, blood pressure and lung function. We are studying the control of a key sodium channel (the epithelial sodium channel) and a key chloride channel (cystic fibrosis transmembrane conductance regulator) by an enzyme called Nedd4-2. This project will enable us to understand how Nedd4-2 regulates these two ion channels and to study the pathological consequences of the loss of Nedd4-2.
Pharmacological Preconditioning And Sodium/hydrogen Exchange Inhibition To Optimise Preservation Of The Donor Pig Heart
Funder
National Health and Medical Research Council
Funding Amount
$242,545.00
Summary
Heart transplantation has become established as an extremely beneficial treatment for patients with end-stage heart failure, however its success is limited by the restricted availability of donor hearts. Many hearts that could be considered for heart transplantation cannot be used because of damage that can occur to potential donor hearts after the death of the donor. This damage is caused in part by deterioration in heart function after death and in part by the process of removal and cold stora ....Heart transplantation has become established as an extremely beneficial treatment for patients with end-stage heart failure, however its success is limited by the restricted availability of donor hearts. Many hearts that could be considered for heart transplantation cannot be used because of damage that can occur to potential donor hearts after the death of the donor. This damage is caused in part by deterioration in heart function after death and in part by the process of removal and cold storage that occur prior to transplantation of the heart. This study will examine two new methods of optimising the quality and preservation of the donor heart for transplantation. The treatments to be investigated in this study are aimed at preventing damage to the donor heart after death and during the process of transplantation. The studies will be conducted in a pig model of heart transplantation that we have developed in our laboratory. The treatments will be administered to the donor pig after induction of brain death and also to the recipient during transplantation of the heart. As the model closely mimics all aspects of human heart transplantation, any positive findings that stem from these studies will be directly applicable to human transplantation. Improved preservation of the donor heart will make the operation safer and will potentially increase the number of hearts that can be used for transplantation. As many donors provide multiple organs for transplantation eg kidneys, liver, lungs and pancreas, the treatments that we are investigating have the potential to improve the recovery of all these organs after transplantation.Read moreRead less
Altered Intracellular Signalling In Response To Hyperglycaemia Reflects An Inherent Predisposition To Nephropathy
Funder
National Health and Medical Research Council
Funding Amount
$164,061.00
Summary
Diabetic nephropathy affects 30-50% of patients with diabetes mellitus. The reasons as to why only a proportion of patients develop this devastating complication is not clear. Poor control of blood sugar levels has been well characterised as being of aetiological importance in its genesis, but is clearly not the sole factor responsible. Genetic factors appear to predispose individuals to developing diabetic nephropathy, with a significantly higher number of affected patients having a family hist ....Diabetic nephropathy affects 30-50% of patients with diabetes mellitus. The reasons as to why only a proportion of patients develop this devastating complication is not clear. Poor control of blood sugar levels has been well characterised as being of aetiological importance in its genesis, but is clearly not the sole factor responsible. Genetic factors appear to predispose individuals to developing diabetic nephropathy, with a significantly higher number of affected patients having a family history of hypertension and vascular disease. Our own preliminary studies using cells from human kidneys have demonstrated that there are clearly 2 responses observed with respect to alterations in intracellular signalling after exposure to high glucose concentrations and hormones known to be of importance in the development of diabetic nephropathy (such as angiotensin II and insulin-like growth factor-1). These responses appear to be specific to the patient from which the kidney tissue is derived. Thus the aim of the present study is to determine prospectively, whether the groups differ with regards their intracellular signalling and subsequent development of tubulointerstitial pathology in an in vitro model of diabetes mellitus.Read moreRead less