The discovery of Alzheimer’s disease through a simple blood test is closer than ever after many years of research, marking a revolutionary development in the field. However, patients themselves will not benefit from this unless effective treatments for the disease are made available after a long wait. Neurologist Giovanni Frisoni, one of the leading European specialists in Alzheimer’s, stated, “Blood biomarkers will change the way we diagnose [the disease].”
The method of diagnosing in this way has been a main focus of research for many years related to the disease, which is considered the most common form of dementia and irreversibly affects tens of millions of people worldwide. The idea is to provide the ability to detect through a simple blood test indicators that reveal the physiological mechanisms by which the disease begins.
Scientists have reached data concerning two main mechanisms, without fully understanding the interaction between them. The first involves the formation of what is known as amyloid protein plaques in the brain, which pressure and eventually destroy nerve cells. The second is the accumulation of another protein called tau within the nerve cells themselves.
Currently, tests are available to detect Alzheimer’s disease, one through lumbar (or spinal) puncture and the other through one of the medical imaging techniques, which is positron emission tomography (PET). However, since these tests are lengthy, burdensome, and costly, many patients settle for clinical results such as severe memory loss.
Some blood tests have previously been introduced to the market, but only a few are practically used while waiting for data on their actual utility. However, many studies have recently demonstrated the effectiveness of some blood tests in detecting internal signs of the disease. One of the most notable studies was published last January in the journal "JAMA Neurology." The study, which tracked around 800 people, concluded that the blood test could reveal an abnormal amount of amyloid or tau proteins with similar effectiveness to the currently approved tests.
Most importantly, the effectiveness of this test has been confirmed in the preclinical stage, even before the known symptoms of the disease appear. The medical community has generally expressed relief at this important advance, despite some gaps, including the need to confirm this effectiveness in practical applications, and that this test only indicates the existence of physiological mechanisms that do not systematically lead to dementia.
Neurology specialist Bart De Strooper commented through the British Science Media Centre platform that it is "an excellent study that significantly approaches the potential use of a regular blood test to monitor Alzheimer's disease." In the United Kingdom, this development has almost become a reality. A program initiated by several Alzheimer’s advocacy organizations since last year aims to test the utility of these blood tests within the British healthcare system.
However, discovering the disease at an early stage loses its significance in the absence of any effective treatment. Nevertheless, many neurologists currently hope that new drugs will achieve the desired outcome. After decades of research failing to find treatments, there appear to be two promising drugs, one from Eli Lilly and the other from Biogen, that could slow the progression of Alzheimer’s disease by targeting amyloid plaques.
Although their effectiveness is limited and their side effects are severe, many neurologists view them as a first step toward more effective treatments. In light of this, it is hoped that the ability to use a simple blood test to monitor Alzheimer’s as quickly as possible will enhance the effectiveness of any drug.
An important detail is that the blood test allowed early diagnosis in patients who already suffer from memory impairment, not in just anyone. Frisoni stated, “There is no benefit today in testing blood biomarkers in individuals who do not have cognitive impairment, as this will only lead to harm.”
So what is the benefit of discovering an increased risk of developing the disease if there are no concrete means to prevent its onset? Nevertheless, Frisoni does not rule out the possibility that Alzheimer’s testing will eventually become a reality. He said, “We are currently testing some drugs aimed at reducing the risk of Alzheimer’s dementia.” He added, “Perhaps in five or ten years, that will be a clinical practice. Then, I will be able to recommend measuring blood biomarkers (as a screening tool), but not today.”
