First testing on pigs, then using human subjects, researchers discovered that some metals found in urine samples can help determine whether there is a risk of acute kidney injury (AKI) and expedite treatment.
Researchers have found that certain metals found in people’s urine could potentially point to acute kidney injury (AKI), acting as biomarkers for early detection.
Led by experts from the University of Nottingham’s School of Veterinary Medicine and Science, the study conducted along with clinicians at Nottingham University Hospitals NHS Trust was published in Kidney International Reports.
Acute Kidney Injury (AKI) occurs when kidney function deteriorates rapidly in a matter of hours or perhaps days. It plagues 10 to 20 percent of patients admitted to hospital, while AKI occurrence is much higher in intensive care patients, about 50 percent.
Acute Kidney Injury has many origins, anywhere from serious illness to major operations, from trauma and by medication such as chemotherapy. It affects patients dramatically, increasing their risk of death and chronic disease. A news release puts the cost of AKI to the UK’s NHS (National Health Service) at 1 billion pounds ($1.24 billion) a year.
Doctors agree that one of the main ongoing problems in managing AKI is that it often eludes detection early on at its onset. Many cases of AKI, a news release notes, “are potentially avoidable, or the severity of consequences might be ameliorated with early detection.”
At the moment, doctors diagnose AKI through a blood test that shows an increased amount of serum creatinine, or through observation – patients’ urine output is reduced. These detection methods work; however, they may take more than 24 hours to alert doctors that there is a problem, after which the disease process “might be more difficult to manage.”
Because the detection of AKI is often delayed, and because it is seen in a large population of hospitalised patients, medical companies and doctors have been trying to develop better tests for early detection.
The researchers write that “Various urine and blood biomarkers of early AKI have been described, but none has all characteristics of an ideal biomarker—rapid, easy, and cheap testing; high sensitivity and specificity; and ability to risk stratify and predict clinical outcomes. There remains need for a cost-effective biomarker for early detection of AKI in at-risk patients.”
The research team have previously worked with animals, inducing kidney injury on a group of pigs to test their theory. This model allowed them to identify for the first time “urinary Cd (cadmium), Cu (copper), and iron (Fe) as early biomarkers of AKI.”
The research team worked with patients who were at risk for developing AKI. What they discovered was akin to the animal study: concentrations of the metals rose in urine from AKI patients within an hour after heart surgery, and were higher than they should be on admission in intensive care (ICU) patients.
The research team investigated cadmium and copper in two studies of patients at high risk of AKI: 151 adults undergoing cardiac surgery and 150 adults admitted to general ICU. They also identified zinc as a further AKI biomarker and investigated it similarly.
The press release notes that the biomarkers – alone, or in combination – “had good sensitivity for early identification of patients at risk of moderate to severe AKI and particularly high negative predictive value, suggesting additional efficacy in identifying patients at low risk of AKI.”
Urinary cadmium, copper and zinc offer better clinical and economic options as previously used AKI biomarkers, usually proteins. They can be tested using cheap screen-printed electrodes as opposed to protein assays. They are stable in urine at room temperature, and do not require refrigeration or special storage directions, meaning they can easily be used anywhere in the world, even in places without the highest technology.
“This study is the culmination of 10 years work at Nottingham and is an example of how collaboration between animal scientists, clinicians and local companies can each utilise their expertise to make new and unique discoveries,” says David Gardner, Professor of Physiology at the University of Nottingham. “It is our hope that the research can now be developed further by industry to truly move these discoveries from lab bench to bedside.”
“Acute kidney injury is a common and serious problem in hospitalised patients,” Mark Devonald, consultant nephrologist formerly NUH, currently at Liverpool University Hospitals NHS Foundation Trust, adds.
“Early detection is critical to improving patients’ outcomes. We hope that our findings will help the wellbeing of the many patients at risk of AKI and we are grateful to NIHR and the University of Nottingham for funding our work.”
Source: TRTWorld and agencies