In a study published in the international journal Brain entitled Brain-derived tau: a novel blood-based biomarker for Alzheimer-s disease-type neurodegeneration, scientists from the University of Gothenburg and other institutions have developed a new detection technique that may detect neuromarkers of Alzheimer's disease in patients' blood samples. This named brain derived tau protein (BD-tau) biomarkers due to the current clinical used to detect Alzheimer's disease related neurodegenerative lesions of blood diagnosis technology, for Alzheimer's disease has a certain specificity, but also with cerebrospinal fluid Alzheimer neurodegenerative disease biomarkers has a good correlation.
The diagnosis of Alzheimer's disease currently requires neuroimaging, and these tests are very expensive and often take a long time to perform, and even in the United States, many patients do not have the opportunity to use MRI and PET scans, and the accessibility of these imaging techniques is a major issue, researcher Thomas Karikari said. Therefore, to diagnose Alzheimer's disease, clinical researchers used guidelines developed by the National Institute on Aging and the Alzheimer's Disease Association in 2011. The guidelines, called the AT (N) framework, require detecting three different components of Alzheimer's disease pathology, the presence of amyloid plaques, the presence of tau tangles, and neurodegenerative lesions in the brain, through imaging or analysis of cerebrospinal fluid samples from the patient's body.
Unfortunately, these methods have some economic and practical limitations, urging scientists to develop convenient and reliable AT (N) biomarker tests for blood samples that can collect blood samples with the least invasive means and require relatively little data. The researchers suggest that developing simple tools to detect signs of Alzheimer's disease in the blood without affecting the quality may be an important step toward improving technology accessibility. The most important use of blood biomarkers is to make people live better and improve clinical confidence and risk prediction of Alzheimer's diagnosis, said researcher Karikari.
Current blood diagnosis method can accurately detect β amyloid in plasma and abnormalities in the form of tau protein, which can achieve the diagnosis of Alzheimer's two of the three necessary checkpoints, but the AT (N) framework applied to blood samples the biggest obstacle is that scientists are difficult to detect for the brain very special neurodegeneration markers, but also not affected by the body of other potentially misleading pollutants. For example, the levels of neurocellulose (a protein marker of nerve cell damage) increase in Alzheimer's disease, Parkinson's disease and other dementia, making researchers less useful when trying to distinguish between Alzheimer's disease and other neurodegenerative diseases; in contrast, testing the total blood tau is less valuable than monitoring its levels in the cerebrospinal fluid.
By applying molecular biology and biochemistry to tau in different tissues (such as the brain), the researchers have developed a special technique that selectively detects BD-tau, while also avoiding the free-floating "big tau" protein produced by unexpected cells in the brain. To do this, the researchers designed a special antibody that selectively binds BD-tau, making it easier to detect in the blood. They also subsequently confirmed their trial with over 600 patients from five independent study cohorts, including those diagnosed with Alzheimer's disease after death and those with early Alzheimer's disease with memory deficits. The results showed that the BD-tau levels in the blood samples of Alzheimer's disease can match the level of tau in CSF and reliably distinguish Alzheimer's disease from other neurodegenerative diseases. The level of BD-tau is also correlated with the severity of amyloid plaques and tau tangles in brain tissue confirmed by the analysis of brain anatomy. The investigators hope that testing blood levels in BD-tau will help improve the design of clinical trials and facilitate the screening and recruitment of populations that have not historically been included in the study cohort.
According to Karikari, there are huge diversity of research demands in clinical research, not only according to the color of skin, but also to develop better drugs, clinical trials need to recruit people from different backgrounds, not just those living near the academic medical center; blood testing is very cheap, safe and easy to manage, which can improve clinical confidence in the diagnosis of Alzheimer's disease, and does not select certain participants for research in clinical trials and disease monitoring.
Next, researchers plan to verify BD-tau in the blood on a larger scale, including those recruited from different racial and ethnic backgrounds, from memory clinics, and those recruited in the community. In addition, these studies will include older adults with no biological evidence of Alzheimer's disease and at different stages of the disease. It is important to ensure that the biomarker results are extended to people of all backgrounds, and will pave the way for the commercialization of BD-tau for widespread clinical and prognosis use.
In conclusion, the results of this study show that brain-derived tau may reveal the potential to complete AT (N) strategies in the blood, which in the future may contribute to the evaluation of Alzheimer's disease-dependent neurodegenerative processes for clinical and research purposes.
