Professor Rob Walker
University of Otago researchers are pooling their expertise under the umbrella of the Kidney in Health and Disease Research Theme, led by Professors Rob Walker and Zoltan Endre, to investigate innovative ways to prevent and treat kidney disease (www.otago.ac.nz/kidney).
Patients with chronic kidney disease (CKD) have a six-fold increase in cardiovascular death, while diabetics with CKD have a 20-fold increase in cardiovascular death.
It is estimated that up to one in 11 New Zealanders may have renal disease, based on Australian studies of a similar population, which in many cases is undiagnosed.
The group involves about 20 researchers from Christchurch and Dunedin Schools of Medicine and departments in the wider University. This brings together expertise in areas ranging from molecular- and cellular-level investigations of kidney function, to applying therapies to prevent kidney injury or the progression of kidney disease.
They are involved in a number of trials both nationally and internationally, including two large clinical studies: one looking for markers in the urine that indicate early warning of acute kidney failure; the other studying the effect of lithium - a drug commonly used to regulate mood disorders - on the kidney function.
Walker says the lithium study is important because the psychotropic drug is used widely to treat mood disorders.
"But it also affects kidney function and the way the kidney concentrates the urine," he says. "It can be quite disruptive to that person and can cause irreversible kidney damage."
By developing a better understanding of the key pathways by which lithium gets into the kidneys, they can then look at developing ways to modulate its effects.
Research into developing a tool for early diagnosis of kidney failure is being headed by Endre, who is based at the University of Otago, Christchurch.
Such a tool is of huge potential benefit because the death rate for intensive-care-unit patients with renal failure is between 50 and 80 per cent, while for patients outside the ICU the rate is between 40 and 50 per cent.
Currently they use a blood test to detect creatinine levels, a process that can take days before they can be confident intervention is needed. Often, by the time they see the evidence of renal failure, the damage has already been done.
Endre is part way through a proof-of-concept study testing a urinary biomarker they have identified which can give them a result in as little as an hour.
They are then using this early-detection ability in a world-first trial of early intervention using erythropoietin (EPO) to see if it can prevent patients from going on to develop renal failure.
EPO, better known for its use in sport as an illegal performance-enhancing drug, is already used for anaemia in patients with chronic kidney disease because of its ability to increase red blood cell levels.
Endre's group has already demonstrated that EPO works as a kidney protective agent and also prevents cell death in the kidneys.
It is also thought to stimulate release of stem cells from the bone marrow and may stimulate vascular development during the recovery phase.
Other current research within the research group includes a clinical study to assess the impact of salt intake in blood pressure control.
It's a contentious area, despite good evidence that lowering dietary salt intake is beneficial to health, so this large study, sponsored by the National Heart Foundation of New Zealand, is testing the effects of increased dietary salt intake upon blood pressure control and arterial blood vessel tone.
Participants are initially placed on a low salt diet (National Heart Foundation recommendation) and then randomly receive no added salt, medium salt (typical New Zealand intake) or high salt (typical American intake) supplementation.
"We can then measure how much added dietary salt increases blood pressure and how it changes their blood vessel tone," says Walker.
"This study is relatively simple in concept, but has never been done before."
FUNDING
Health Research Council
National Heart Foundation of New Zealand
National Kidney Foundation
Otago Medical Research Foundation
Canterbury Medical Research Foundation
University of Otago
Marsden Fund
Maurice and Phyllis Paykel Trust