Potential early indicator of kidney injury identified
Dr. Ganesan Ramesh is a kidney pathologist in the Vascular Biology Center at the Medical College of Georgia at Georgia Regents University. Credit: Phil Jones
A guidance cue that helps kidneys form may also be a red flag that they are in danger, researchers report.
Acute kidney injury, a common and serious complication of hospitalization, is on the increase worldwide, affecting an estimated 6 percent of all hospitalized patients and 30-40 percent of adults and children having cardiopulmonary bypass surgery.
About 10-15 percent of acute injuries translate to chronic kidney damage or failure that may require dialysis or a kidney transplant, said Dr. Ganesan Ramesh, kidney pathologist in the Vascular Biology Center at the Medical College of Georgia at Georgia Regents University.
Now, animal and human studies have shown that within a few hours of injury, a significant amount of the protein semaphorin 3A is detectable in the urine, Ramesh and his colleagues report in the journal PLOS ONE.
"Semaphorin 3A appears to be a sensitive biomarker that we believe will give physicians an early and accurate heads-up that their patient's kidneys have been injured so that damage can be minimized and potentially reversed with rapid intervention," said Ramesh, the study's corresponding author.
The protein, which is not usually measurable in urine, was quickly detected in a group of 60 pediatric patients following cardiopulmonary bypass surgery at Cincinnati's Children's Hospital. High levels of the protein were about 90 percent accurate at identifying the 26 children with acute kidney injury. In those patients, urine levels were high within two hours, peaked at six hours and essentially normalized 12 hours after surgery.
Probably because of the kidney's significant reserve capacity, it's more like 48 hours before the current biomarker creatinine, a byproduct of muscle metabolism typically excreted by the kidneys, is elevated in the blood. By then, it's often too late for strategies such as massive fluid volumes, antibiotics and other interventions to yield significant improvement, he said
In the study group, creatinine levels were essentially the same in all 60 children for 24 hours. By 48 hours, levels were significantly elevated in the acute kidney injury group and stayed up for five days.
The researchers initially identified semaphorin 3A in an animal model of temporarily compromised oxygen levels, or ischemia, to the kidneys. When they eliminated the protein's expression in a mouse, it reduced ischemia-related kidney damage.
The hard-working, high-energy kidneys are particularly vulnerable to any decreases in the usual oxygen levels that may result from life-saving strategies such as cardiopulmonary bypass and mechanical ventilation, Ramesh said. Over the course of the day, the kidneys filter the body's total blood volume several times, resorbing needed components like nutrients and eliminating toxins, excess sodium and more. When they stop filtering properly, the body starts dumping both good and bad products into the urine.
Children with congenital heart defects who need multiple surgeries to repair their hearts may be at particular risk for acute kidney injury. In the study, children who developed the injury spent the longest time on bypass and in the hospital.
Many unknowns persist about semaphorin 3A including the role of the guidance cue in the healthy developed kidney and why it's levels shoot up then drop down so dramatically with injury. He notes that there is fairly significant cell turnover in the kidneys so it may have a role in regeneration. Ramesh has already worked with Japanese physicians to look at the levels in 350 older patients in intensive care for a variety of maladies. He's also working on an antibody that will screen specifically for semaphorin 3A.
Journal reference: PLoS ONE
Provided by Medical College of Georgia
- Warning signs predict kidney injury after surgery Aug 12, 2011 | not rated yet | 0
- Markers warn of progressive kidney problems after heart surgery Mar 01, 2012 | not rated yet | 0
- New lab test predicts risk of kidney injury after surgery Mar 12, 2008 | not rated yet | 0
- New kidney protein speeds/improves the diagnosis of failing kidneys Jun 03, 2008 | not rated yet | 0
- Researchers find pet kidney injuries are similar to human kidney injuries Dec 19, 2011 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
Gourmands and foodies everywhere have long recognized ginger as a great way to add a little peppery zing to both sweet and savory dishes; now, a study from researchers at Columbia University shows purified components of the ...
Diseases, Conditions, Syndromes 5 hours ago | not rated yet | 0
There are significant cost and risk factors associated with two procedures commonly used to diagnose or treat gastrointestinal problems, according to research presented at Digestive Disease Week (DDW).
Diseases, Conditions, Syndromes 18 hours ago | not rated yet | 0
Regular consumption of coffee is associated with a reduced risk of primary sclerosing cholangitis (PSC), an autoimmune liver disease, Mayo Clinic research shows. The findings were being presented at the Digestive Disease ...
Diseases, Conditions, Syndromes 18 hours ago | not rated yet | 0 |
A new case of the deadly coronavirus has been detected in Saudi Arabia where 15 people have already died after contracting it, the health ministry announced on Saturday on its Internet website.
Diseases, Conditions, Syndromes May 18, 2013 | not rated yet | 0
(HealthDay)—Few randomized clinical trials have been done to assess clinical prediction rules for patients with lower back pain, and the trials that have been done are of low quality and do not provide ...
Diseases, Conditions, Syndromes May 17, 2013 | not rated yet | 0 |
Researchers at the University of Wisconsin have identified a potential new risk factor for obstructive sleep apnea: asthma. Using data from the National Institutes of Health (Heart, Lung, and Blood Institute)-funded Wisconsin ...
5 hours ago | not rated yet | 0 |
A new study looking at sleep-disordered breathing (SDB) and markers for Alzheimer's disease (AD) risk in cerebrospinal fluid (CSF) and neuroimaging adds to the growing body of research linking the two.
6 hours ago | 5 / 5 (1) | 0 |
In their quest to learn more about the variability of cells between and within tissues, biomedical scientists have devised tools capable of simultaneously measuring dozens of characteristics of individual ...
6 hours ago | 5 / 5 (1) | 0 |
Scientists at Johns Hopkins have turned their view of osteoarthritis (OA) inside out. Literally. Instead of seeing the painful degenerative disease as a problem primarily of the cartilage that cushions joints, ...
6 hours ago | 5 / 5 (2) | 0 |
The hunt for an HIV vaccine has gobbled up $8 billion in the past decade, and the failure of the most recent efficacy trial has delivered yet another setback to 26 years of efforts.
10 hours ago | not rated yet | 0
The devastating effect of Alzheimer's disease on bilingual people has been thrown into focus in Canada, where the sudden loss of a second language can leave sufferers feeling like strangers in their own country.
8 hours ago | not rated yet | 0