Could a new blood test identify kidney damage earlier?
New research has been published in Nature Communications, led by Dr Matthew Butler, Professor Simon Satchell and their team at the University of Bristol. The study, funded by Kidney Research UK and the Medical Research Council, shows a blood test could detect damage to the tiny blood vessels of the kidneys. These tiny blood vessels become damaged at the early stages of certain diseases, including some types of vascular and kidney disease.
Blood vessel health is linked to kidney disease
Our blood vessels are lined by a thin, gel-like layer, called the glycocalyx. In the kidney, the glycocalyx forms part of the network that filters blood. This filtration process allows us to keep useful substances in our blood and get rid of waste in the urine. The glycocalyx is damaged in some diseases that affect the kidneys, such as diabetes. This damage causes the tiny blood vessel filters to become leaky, and the kidneys function less well, allowing substances usually kept in the blood, such as protein, escape into the urine
Could a blood test tell us about blood vessel health in the kidneys?
Our blood contains red blood cells which transport oxygen and waste products such as carbon dioxide around our body. Red blood cells also have a glycocalyx on their surface. Matthew, Simon and the team studied the glycocalyx on red blood cells and compared this to the glycocalyx of the blood vessels in the kidneys in a laboratory model and in human kidney biopsy samples. Damage and thinning of the glycocalyx was shown in the tiny kidney blood vessels in certain diseases affecting the kidneys, such as diabetes. This thinning of the glycocalyx was mirrored on the red blood cells.
Matthew, Simon and the team then looked at whether a blood test could be used to predict the health of the tiny blood vessels in patients. In a group of pregnant patients, who donated blood samples and had a test to measure the glycocalyx thickness of their blood vessels, they again found the thickness of the glycocalyx was mirrored between the red blood cells and blood vessels.
To look at why the glycocalyx health was similar between the tiny blood vessels and red blood cells, the team studied the components of the glycocalyx. They found that some components, such as certain sugars, were exchanged between the red blood cells and cells lining blood vessels when they came into contact. Therefore, damage to the glycocalyx of our blood vessels is reflected on the red cells in our blood.
A blood test could detect early damage to tiny blood vessels in kidney disease
Damage to the glycocalyx of the tiny blood vessels in the kidney happens in the early stages of certain diseases, such as diabetes. This research could provide a new way of assessing the health of the kidneys using a blood test. Identifying kidney disease sooner is key to earlier interventions and treatments to protect the kidneys and improve outcomes for patients.
Hear from the researchers
“We know the microscopic kidney blood vessels are damaged in the earliest stages in some kidney diseases, but they are largely inaccessible to us clinically. Detecting damage to these tiny blood vessels using a blood test would allow us to identify signs of kidney disease earlier than ever before.” Dr Matthew Butler
“These results show a blood test could be used to identify signs of disease affecting the kidneys at a much earlier stage. Earlier identification is key to making proactive interventions to protect kidney health and improving outcomes for patients.” Professor Simon Satchell
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