When it comes to Alzheimer’s disease, an early diagnosis – one made well before signs of irreversible dementia are apparent – is key to providing effective intervention and treatment. Now early detection might be as simple as a urine test, allowing for wide-scale and early screening across large populations of the elderly.
A collaboration of researchers in China investigated urine samples for biomarkers from a large group of patients with varying severity of Alzheimer’s disease, comparing them with healthy controls.
A compound known as formic acid (which is also produced by some ant and bee species) was a particularly sensitive marker for cognitive decline associated with Alzheimer’s disease. Significant increases in urinary formic acid levels were found in all samples from Alzheimer’s sufferers (including those with only early-stage subjective cognitive decline) as compared with those from the healthy controls.
“Alzheimer’s disease is a continuous and concealed chronic disease, meaning that it can develop and last for many years before obvious cognitive impairment emerges,” say the authors. “The early stages of the disease occur before the irreversible dementia stage, and this is the golden window for intervention and treatment.”
When blood samples of the participants were analysed for Alzheimer’s biomarkers in combination with the urinary formic acid level, the researchers were able to predict to what stage of the disease the patient had progressed. Their report is in Frontiers in Ageing.
Other methods currently used to diagnose Alzheimer’s disease, such as positron emission tomography brain scans, invasive blood draws and lumbar punctures, tend to be costly and invasive. Although other urinary biomarkers for Alzheimer’s disease have been found, none have been able to detect the disease at its earliest stages.
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The links between urinary formic acid and Alzheimer’s disease are still not fully understood, but this research is an important step towards developing tools to diagnose and treat this debilitating condition amongst a vulnerable group in society.
“Urinary formic acid showed an excellent sensitivity for early Alzheimer’s screening,” said the authors. “The detection of urine biomarkers of Alzheimer’s is convenient and cost-effective, and it should be performed during routine physical examinations of the elderly.”