Urinary ELISA Kit Developed for Alzheimer's Disease Diagnosis

By LabMedica International staff writers
Posted on 02 Aug 2016

Alzheimer's disease is the most common form of dementia, a general term for memory loss and other intellectual abilities serious enough to interfere with daily life and Alzheimer's disease (AD) accounts for 60% to 80% of dementia cases.

Early, accurate diagnosis of AD is beneficial for several reasons as beginning treatment early in the disease process may help preserve daily functioning for some time, even though the underlying Alzheimer’s process cannot be stopped or reversed.

$Image: A histopathology section of brain tissue from an Alzheimer\'s patient showing neurofibrillary tangle and neuritic plaque (Photo courtesy of Dr. Dimitri P. Agamanolis, MD).$

Image: A histopathology section of brain tissue from an Alzheimer\'s patient showing neurofibrillary tangle and neuritic plaque (Photo courtesy of Dr. Dimitri P. Agamanolis, MD).

Scientists at the Capital Medical University (Beijing, China) have developed noninvasive and simple method for early detection of AD, which will be extremely important for the diagnosis and prognosis of AD. They aimed to develop an enzyme-linked immunosorbent assay (ELISA) kit to detect urine Alzheimer-associated neuronal thread protein (AD7C-NTP), and to evaluate its clinical value for the diagnosis of AD.

The scientists collected the first morning urine specimens of 121 AD patients and 118 age-matched controls, and the urine AD7C-NTP levels were detected by the ELISA kit. The team synthesized immunogenic AD7C-NTP peptide fragments by the solid-phase method and used for immunizing mice or rabbits to generate anti-AD7C-NTP antibodies. The urine AD7C-NTP ELISA kit was then established; the generated mouse anti-AD7C-NTP antibody was used as a capture antibody, the biotin-labeled rabbit anti-AD7C-NTP antibody was used as a detection antibody, and avidin labeled by horseradish peroxidase was used as a substrate.

The investigators reported that mouse and rabbit anti-AD7C-NTP antibody ELISA titer was found to be 1:8,000 and 1:32,000, respectively. A single band with a relative molecular mass of 41 kDa was found in human brain specimens by Western blot assay, which was identified as AD7C-NTP antibody. The urine AD7C-NTP concentration of the AD patients was higher than that of the age-matched controls, the sensitivity was 89.3% and the specificity was 84.7%.

The authors concluded that they had successfully demonstrated that their newly developed urine AD7C-NTP ELISA kit has suggested potential for diagnosing AD in a Chinese population, suggesting it may be a useful diagnostic kit for detecting early AD. The study was published in the July 2016 issue of the Journal of Clinical Laboratory Analysis.

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Capital Medical University