Similarly, nerve cell loss from the retina in Alzheimer's disease has been proven time and time again. However, it can often not be said with certainty that the loss is exclusively related to Alzheimer's disease. It may also be involved in other age-related diseases, such as diabetes, cataracts or macular degeneration.
In any case, Jochen Herms of the German Center for Neurodegenerative Diseases in Munich concluded on the theme "retina". A few years ago, as part of a project in collaboration with Zeiss, Herm's team attempted to develop a diagnostic tool based on the beta-amyloid and tau molecules in the retina. "What worked well in experiments on mice did not succeed in humans," Herms says. The scientific community is diverted from the majority of the eye diagnosis approach, so Herms.
Blood instead of cerebrospinal fluid
In the meantime, careful examination of the cerebrospinal fluid has been attempted for many years with an unnecessary blood test. This would also be suitable for routine examinations. "Until now, no blood test close to the brain's sensitivity to the examination of brain water has been developed," Oliver Peters explains of Charity. Blood contains many other proteins than CSF, which makes it difficult to detect and falsify the result.
Nevertheless, researchers are trying to detect suspicious signals, such as proteins, metabolites, RNA molecules or DNA. Yanfeng Jiang and colleagues at Fudan University in Shanghai, in a recent study, believe that blood tests will predict the course of dementia or identify people at high risk of dementia in the future. Researchers, for example, suggest a combined measure of different hormones, lipids, amino acids, and metabolites. However, it is still unclear which "models" are typical of Alzheimer's dementia (nascent).
The immune cells of patients with Alzheimer's disease behave differently at an early stage compared to those of healthy subjects.
Max Holzer of the Paul Flechsig Institute for Brain Research at the University of Leipzig focuses on the informative value of immune cells for the diagnosis of Alzheimer's disease. "There is a dialogue between the immune system and the brain, Alzheimer's leaving traces in the immune system," says Holzer. The immune cells of patients with Alzheimer's disease already behave at an early stage of the disease, while patients show only mild symptoms, unlike those of healthy subjects. When immune cells isolated from the blood are activated in the laboratory, those of patients with Alzheimer's disease carry less of a particular molecule, called CD69, on the surface of their cells. That they do it, well before the disease becomes visible, remains unknown. The University of Leipzig has just sold a license for further development of the test to an American biotechnology company. If and if so, what test for early detection will race once, you can not even estimate, says Max Holzer.
Research on biomarkers is hampered by the fact that not all tired patients are necessarily affected by Alzheimer's disease. Mental capacity can also decrease with age or other illnesses. In addition, we usually meet people who already have cognitive deficits (at least slight). After all, healthy people do not go to doctors' offices or clinics.
Mathias Jucker has found a solution to this problem. He is primarily looking for people likely to contract Alzheimer's disease at almost 100% because of a genetic modification, he says. These women and men are about the same age as their parents with Alzheimer's disease, usually between 40 and 50 years old. Since the genetic variant of Alzheimer's is very rare, the families affected in the world are summarized in a research community called DIAN (Eng. Predominantly hereditary Alzheimer's network) together. "This is a special opportunity to study biomarkers and clinical evolution well before the onset of symptoms," says Johannes Levin of the Center's Studies Center. Munich from the DIAN study at the Munich LMU.
Already 10 to 15 years before the onset of the disease, one can detect the death of the first brain cells with the help of a blood test.
For the first time in this group of people, the disease began to appear 20 years before the onset of symptoms, said Mathias Jucker. And now, thanks to the sampling equipment of the affected people, another breakthrough has been achieved: already 10 to 15 years before the onset of the disease, the death of the first brain cells can be proven to help of a blood test. "Our blood test does not measure amyloid, but what it does in the brain, namely the death of nerve cells," Jucker says. The blood test detects a small fragment of what is called "neurofilament," or NfL. It is a component of the internal skeleton of nerve cells, which is relatively resistant to the processes of degradation in the blood. Obviously, this tiny fragment is very well suited to measure the extent of damage in the brain. The amount of NfL detected in the blood and cerebrospinal fluid may be related to the degradation of brain tissue: the greater the degradation, the higher the rates are.
The blood test is promising, but needs to be clarified before routine application, which may distort the NfL value. This can also be increased in other diseases of the brain and kidneys, said journalist Hildegard Kaulen in the "Frankfurter Allgemeine Zeitung". "Jucker and his colleagues also need to clarify whether the blood test has the same predictive value in sporadic Alzheimer's disease as it does in DIAN families," Kaulen continues.
Early detection – why?
"Before having drugs to treat Alzheimer's disease, early detection makes no sense," says Mathias Jucker. However, it takes biomarkers for the development of the drug itself, which can be used to test whether a drug tested is effective or not, says Jucker. His colleague Frank Jessen of the clinic and the polyclinic of psychiatry and psychotherapy of the University of Cologne does not currently organize screening for people with no symptoms.
On the other hand, in the case of patients with mild cognitive impairment, things are different. "I think the disease should be detected and diagnosed quickly by biomarkers, so you can have early intervention," says Jessen. Oliver Peters, head of memory consulting at Berlin Charity, also believes that an early diagnosis is important. Patients diagnosed with Alzheimer's disease at an early age might receive important advice, such as advice to dispense with general anesthesia when needed. Stress and other physical stresses such as anesthesia can lead to a sudden worsening of the neurodegenerative disease. "What's the use of a new hip joint if I can walk better after surgery, but I can not orient myself," Peters explains. Perhaps you could also influence the course of the disease. A study of more than 1,000 participants suggested that dementia can improve if you eat healthier and move more.
It may be that the tests reveal that it is not Alzheimer's disease, but memory, language and orientation problems have another cause that can be treated, such as that which is not the case. thyroid dysfunction or vitamin deficiency. "When symptoms appear, always specify where they come from.Sometimes you can correct the causes and your memory will improve," says Jochen Herms.
Anyone who fears that something is wrong with himself or a close family member should go to a memory consultation, advises Herms. "The psychological tests done there are very good at seeing changes in brain performance." Such a study is logical in all cases, even if no anomaly has been found. Because every human brain has completely individual abilities. In order to quickly detect a mental deterioration, ideally, at least two tests, which are performed in a (higher) time interval, are required. "Changes in brain performance are much easier to master when there are preliminary examinations," says Herms.