by Christian Behl

Almost everybody wants to grow old, but who wants to be old? The demand for the maximum life span, for anti-aging strategies and the ageless body are main topics of our current society. The whole discussion on the "obsession of youth", "anti-aging", or "lifestyle," and now the almost obvious possibilities to restore body tissue from hair to skin, or the exchange of organs has forgotten something important: Our nervous system, especially our nerve system, the brain, is also exposed to the aging process. But the brain cannot be lifted like the face - it is not exchangeable.

Forgetfulness caused by old age is often confused with Alzheimer's related dementia, which is the most well-known form of dementia exhibited by people. Yet, while a little forgetfulness must be allowed for the elderly, Alzheimer's disease-dementia is a rapidly progressive, neurodegenerative, fatal disease. First described 100 years ago by Aloys Alzheimer, Alzheimer's disease is one of the most researched medical problems of man today and the subject of many research projects in medical laboratories and the pharmaceutical industry worldwide. The hope of molecular science is to heal people from this disease by relatively simple biochemical procedures. After 100 years of research on Alzheimer's, unfortunately only a slight reduction of the symptoms is possible through therapy so far. A causative therapy is not in sight today.

Alzheimer's disease – an epidemiological problem

Against the backdrop of the continually growing life expectancy of man, it is assumed there is a remarkable movement in the former age pyramid towards older age groups. Age-related diseases like adult onset diabetes, arteriosclerosis, cancer and especially diseases of the nervous system like Alzheimer's disease, become a burden of the aging society. The need for a causal therapy will become even more urgent than it is today. Today there are  around 24 million Alzheimer's patients worldwide. During the coming decades a sharp increase in the disease is expected - especially among the present developing countries. In Germany alone there are currently about 1 million people suffering from Alzheimer's, the estimated number of unreported cases is certainly very high. Every year, 200,000 new cases are registered.

Possible causes of Alzheimer's disease

The fundamental medical research, which deals with the defintion of complex diseases, often tries to draw conclusions from the basis of hereditary diseases to the biochemical origin of this suffering. This also applies to the Alzheimer's disease, which also can be seen as a result of genetic transformation (mutation). These genes and their genetic products, certain proteins, are now known, though, only approximately five percent of all Alzheimer's patients suffer from this genetic form of the disease ("Amyloidhypothese"). The vast majority suffers from a sporadic type without a concrete, clearly defined genetic background. In the last century, through the help of a few known genetic cases, a multitude of molecular steps have been gathered related to the development of Alzheimer's disease. These mechanisms cannot be transferred strictly to the cases that are caused by age, which is the reason for the disease in the majority of patients. For those, age and age related molecular and cellular transformations, as well one’s previous history (for example previous illnesses, comorbidity), are the only reproducible and confirmed risk factors.

Several different hypotheses are discussed based on molecular causes. For instance, the influence of the deposit of proteins consisting of an adhesive "amyloid protein" or the hardening inside of neurons, which are composed of so-called "Tau proteins". Other possibilities are vascular changes due to the failure of the lipid metabolism. Further hypotheses are presently being worked on. The aim of most research driven approaches is to prevent the formation and deposit of amyloid protein, for instance, by blocking the enzymes that are responsible for the formation of amyloid or by removing the protein aggregates that have already formed through an induced reaction by an injected vaccination. However, these approaches are still in the early stages. Until now, it is unclear if they can be transferred through casual therapy to the large number of Alzheimer's patients.

What can be done today?

Since the possible therapeutic approaches are primarily concentrating on the strengthening of signal conductions between the neurons (neurotransmission), for example, during memory formation, and therefore can only cure symptoms, prevention gains particular relevance. In this respect, diet plays a central role. It is advisable to have a sufficient amount of vitamins and an equally well-balanced fat and cholesterol intake. These are the same provisions recommended to patients for the prevention of atherosclerotic changes. Additionally, there is much discussion about the English saying, "use it or lose it," on the constant use of the brain and training in terms of "brain jogging," which also might have a strong preventive effect. In fact, several observations have shown that elderly people who spend time on complex texts and memory tasks (such as crosswords, chess and so on) have a considerably lower risk of having Alzheimer's than people who are not as mentally active. Likewise, the integration of old people in the social environment and the avoidance of isolation, for example, in nursing homes, are essential for the prevention of forms of dementia.

Old Age – The Main Reason for Dementia