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TREATMENT STRATEGIES OF ALZHEIMER’S DISEASE: DRUGS TO IMPROVE MENTAL FUNCTIONINGThe discovery that the brain lacks adequate quantities of important chemicals such as the neurotransmitter acetyl choline resulted in a search for medication that would rectify either the deficiencies concerned or the results of these deficiencies. Traditionally there are three approaches to trying to deal with a situation in which a chemical is missing from the brain. The first approach is to give the body more of the chemical in the hope that it will be passed to the brain, where it can carry out its normal function, or to provide the brain with other substances that it may be able to convert into the missing chemical. This approach has been tried for Parkinson’s disease and has been very effective in treating the symptoms in many people, although it doesn’t prevent the progress of the disease. For the treatment of Alzheimer’s disease, however, the results have been disappointing. Perhaps the best-known substance to have been tried is lecithin for which there have been many trials, some attempting to show an improvement in intellectual function and others with the more modest objective of showing that it might prevent or slow down further deterioration. There has however been very little evidence that lecithin and similar compounds have been beneficial. A second approach to help the brain cope with a reduction in the level of an essential substance is to try to ensure that the little that is available lasts for as long as possible. Like most tissues in the body, the brain has the chemical processes to enable it to destroy most chemicals it is designed also to produce. This is essential in biological systems where a balance between production and destruction has to be maintained. We know that there are some drugs that slow down the destruction of acetyl choline and similar compounds, and it was hoped that the administration of these might result in a prolonged life for the small amounts of neurotransmitter produced, with an improvement in intellectual function. Until recently this technique also seemed to be disappointing, but a new substance called tetrahydroaminoacridine (THA) has proved worthy of further evaluation. Significant improvements in intellectual ability were originally claimed for THA, but although these have failed to be substantiated by subsequent trials, it is beginning to look as if a proportion of patients with Alzheimer’s disease, but not other dementias, may acquire modest improvements in ability and behaviour with this drug. It is, unfortunately, a drug that produces many side-effects which may preclude its ever being generally available on prescription. It may, however, show us the way to development of more effective and safer drugs. Perhaps we have our feet one or two rungs up from the bottom of the long ladder of drug development for Alzheimer’s disease. The third approach to dealing with a reduction in the amount of a neurotransmitter in the brain is to try to make the brain structures that are switched on by the depleted chemical more sensitive to the reduced amounts available. Although this approach is used in other neurological diseases with a modest degree of success, it has so far failed to be of much benefit to people with Alzheimer’s disease. Since approaches aimed directly at affecting the missing chemicals have been unsatisfactory, although as mentioned THA is under further evaluation, researchers have turned to other methods of trying to improve brain function. One of the most exciting of these is the attempt to prevent or slow down the rate of cell death of the factory cells that produce the neurotransmitter chemicals. In other words, rather than trying to replenish the brain’s level of neurotransmitters by using tablets or injections that contain the missing chemicals or those that can be made into them, an attempt is being made to see whether it is possible to discover why the factory cells are dying or not working properly, in the hope that they can be made to fulfil their normal function once again. A modest degree of success has been achieved in understanding what is happening to these factory cells although it is not yet known whether this knowledge can be translated into an effective therapy. It seems as if some of the cells in the brain that make neurotransmitters need substances called trophic factors in order to carry out their normal functions and there is a suggestion that in some degenerative diseases of the brain, including Alzheimer’s disease, these trophic substances may be missing. It is hoped that it may be possible to supply the appropriate trophic factors to enable the cells to work properly, so that they in turn may produce the neurotransmitters that are required for normal brain functioning. Although this field of research holds great promise, it is too early yet to know whether it will be an effective form of treatment. As well as the specific attempts to try to put right the biochemical abnormalities that occur in the brain in Alzheimer’s disease, there have been many other, rather more general approaches to developing drug treatments that may improve dementia, almost irrespective of the underlying cause. All sorts of drugs have been tried. Many of them were originally developed as vasodilators — medicines that would cause dilation of the blood vessels thereby improving the blood circulation to the brain. It is now known that this type of approach is unlikely to be of any benefit since it does not improve any of the conditions that cause dementia. Other drugs were thought to improve the metabolism — the biochemical processes — within cells and these too have proved disappointing. Many other methods have been tried, but so far, with the exception of people who have a treatable cause for their dementia such as a vitamin deficiency, there is no evidence that any medicine that is generally available is of any benefit in improving intellectual performance. This situation may change, however, within the next two or three years. *111\138\2* Related Posts:Tags: General Health Leave OneYou must be logged in to post a comment. |
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