The Alzheimer disease It is the most frequent type of dementia associated with aging. Unfortunately, to this day there is no therapy or treatment that can cure it, but there are some drugs available on the market that can help alleviate some symptoms. Especially if they are administered before these are severe.
That is one of the reasons why early diagnosis of the disease has become a priority. But in addition, detecting it in time improves the quality of life of patients. To which is added that early diagnosis would also allow them to participate in clinical trials with a greater probability of success.
Typically, this dementia is diagnosed through a complete clinical evaluation by a neurologist or gerontologist, including neurological, neuropsychological, brain imaging, and, in certain cases, genetic testing.
However, recently different tests are being developed for the analysis of biological samplessuch as blood, which would allow earlier, more accurate and cheaper detection.
Memories and resonances to detect Alzheimer’s
The neurological examination includes a complete physical examination to assess brain function, reflexes, and coordination, while the neuropsychological evaluation consists of a series of tests designed to analyze memory, language, learning and reasoning ability, and other cognitive functions. . Among them are the MoCA test and the minimental.
On the other hand, brain images such as those provided by positron emission tomography (PET) can show accumulations of toxic proteins associated with Alzheimer’s, such as amyloid plaques and the neurofibrillary tangles. In addition, magnetic resonance imaging (MRI) makes it possible to broadly assess the state of the brain, making it possible to identify atrophies (reduction in size) of regions associated with cognitive functions such as memory. However, these tests are often expensive and are not always used.
In addition to this, the analysis of cerebrospinal fluid (which bathes, surrounds and cleanses our central nervous system) can detect biomarkers associated with Alzheimer’s such as beta amyloid and hyperphosphorylated tau protein. Both can accumulate in the brain 10 to 20 years before clinical symptoms appear, and their early detection is a very reliable indicator that the disease has begun to develop. The negative point is that, to obtain these samples, it is necessary to perform an invasive lumbar puncture.
The genetic clues to Alzheimer’s
On certain occasions, genetic tests can provide information about the origin of the disease. Today, more than 70 DNA regions are known that can predispose us to developing this dementia. However, these tests are not routinely performed at this time.
Specifically, in a small percentage of cases (less than 1%) there are mutations in one of the three known genes, called APP, PSEN1 and PSEN2, which cause the onset of familial Alzheimer’s. This is characterized by starting before the age of 65 and usually affects several members of the same family.
In rare (most) cases, genetic testing can provide information about whether a person has certain genes that increase the risk of developing Alzheimer’s, including the ApoE4 isoform.
A routine blood test will put us on notice
Toxic proteins present in the brains of Alzheimer’s patients have also been found in small amounts in blood samples from patients. This is explained because, after cleaning the brain, the cerebrospinal fluid is poured into the blood so that waste can be removed from the body. And that opens the doors to a minimally invasive and inexpensive way to diagnose and follow the evolution of this dementia.
Currently, there is no blood test that can definitively diagnose Alzheimer’s disease, but there are multiple ongoing investigations. In addition to beta amyloid and tau protein, other biomarkers have been identified that may also be useful for early diagnosis of the disease, such as amyloid precursor protein (APP), glial fibrillary acidic protein (GFAP) and protein the neurofilament light chain (NfL). The detection of these markers would not only indicate the presence of a neurodegenerative disease: since their quantity varies according to severity, analyzing them also allows us to know the progress and severity of the disease.
Specifically, the GFAP It is a protein present inside astrocytes, one of the main cells of the brain’s immune system. Its presence in the blood indicates that the brain is undergoing a chronic inflammatory process that could be related to a neurodegenerative disease.
Similarly, C-reactive protein (CRP) is a non-specific marker of inflammation and has been shown to increase both in the brain and in the blood serum of people with Alzheimer’s. and can indicate a higher prevalence of suffering from it.
Refering to NfL presence in blood, also alerts that a neurodegenerative process is taking place in the brain, with neuronal death.
Therefore, early diagnosis could consist of a combination of routine blood tests to detect toxic proteins, but also biomarkers of neuronal death and brain inflammation, which would add to current detection methods.
This non-invasive, rapid, and low-cost method of detection would greatly improve the diagnosis of Alzheimer’s disease. And everything indicates that they could be available in primary care in at least ten years, although their routine use could take longer to be implemented.
Ines Moreno GonzalezRamón y Cajal Professor and Researcher in Neurodegenerative Diseases, CIBERNED, IBIMA, Malaga University
This article was originally published on The Conversation. read the original.
