The new discovery raises hope that Alzheimer’s can be diagnosed years before symptoms appear, which could make medications or lifestyle changes more effective in preventing the disease’s complications.
A definitive diagnosis of Alzheimer’s was not possible until someone had died, but recent biomarker research has led to the development of imaging techniques and cerebrospinal fluid tests for those who are still alive.
However, tests can only track severe disease and distinguish advanced Alzheimer’s disease from similar disorders.
According to ACS Chemical Neuroscience, researchers have identified a biomarker that could help doctors diagnose Alzheimer’s disease early, when a patient develops mild cognitive impairment (MCI), an early sign of the disease.
In the search for biomarkers for Alzheimer’s disease, some researchers have turned to studying subtle changes in a protein called tau. These changes or alterations may increase the likelihood of tau accumulation, leading to neuronal loss and memory impairment.
Two of these modifications involve the phosphorylation of tau at certain amino acids, resulting in transcripts called p-tau181 and p-tau217. These biomarkers have been shown to effectively distinguish tissues from people with Alzheimer’s disease from those from people with other neurodegenerative diseases.
Because it is useful to have multiple biomarkers in the hands of clinicians, Ben Xu, Jerry Wang and their colleagues have been looking for additional biomarkers for p-tau that could be effective in diagnosing Alzheimer’s disease, or possibly identifying early stages of Alzheimer’s disease. .
Using post-mortem brain tissue from patients with Alzheimer’s disease and without ADZ, the researchers identified several p-tau biomarkers that are selectively associated with tau protein aggregation. Like p-tau181 and p-tau217, some of these biomarkers distinguished tissues from Alzheimer’s patients from healthy controls. p-tau198, in particular, distinguishes Alzheimer’s disease from two other neurodegenerative diseases in which tau is known to be deposited.
Further experiments showed that p-tau198 was as effective as p-tau181 and p-tau217 in these tests. Importantly, both p-tau 198 and p-tau217 can also differentiate the brain tissue of patients with mild cognitive impairment, an early hallmark of Alzheimer’s disease, from older adults who do not. According to the researchers, there are currently no well-established biomarkers that could diagnose mild cognitive impairment.
Thus, p-tau198 and p-tau217 may help clinicians intervene early, when new treatments become available, before significant neurological damage occurs.
In addition, the researchers say the method could be used to search for tau biomarkers with modifications other than phosphorylation.
Source: Medical Express