Alzheimer’s Disease
Along with the development of modern technologies, going to the moon and other exciting developments humans face the threat of diseases that affect the process of life and can be lethal in some cases. One of the illnesses that have a great affect on people’s behavior is Alzheimer’s disease (AD). Alzheimer’s disease is the degenerative disease of the brain among old people from which there is no recovery. Slowly the disease attacks the brain cells in all parts of the brain and some surrounding structures, so the an ill person loses the previous abilities to govern emotions, understand mistakes, coordinate his movements and finally a person loses all of his memory and ability to mentally function (B. Heights 2002).
AD is named after German doctor Alois Alzheimer. Dr. Alzheimer noticed changes in the brain tissue of a woman that died of an unusual mental illness. He found abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary tangles). Today, these plaques and tangles in the brain are considered hallmarks of AD. Many scientists have found other brain changes in people with AD. There is a loss of nerve cells in areas of the brain that are vital to memory and other mental abilities. There also are lower levels of chemicals in the brain that carry complex messages back and forth between nerve cells. AD may disrupt normal thinking and memory by blocking these messages between nerve cells (H. Simon).
Scientists are finding specific biologic factors (Peter, Konrad, and Ballenger 2000) involved with the AD. Different environmental and genetic aspects take part in causing AD. However, the actual cause of the disease is still unknown. The greatest known risk factors for late-onset Alzheimer’s are increasing age and a family history of AD. Researches all over the world are trying to find other factors that can cause AD.
AD is nowadays the fourth leading cause of death among the adults. Nearly four million Americans have it. The number doubles every five years in people over sixty five years old. By the age of eighty five almost half of Americans have AD. Some studies show that women have much higher risk of being affected by the AD than men (most of these studies were conducted on European and Asian populations, the U.S. studies, however, found no major differences). If there is a gender difference, then it is because of estrogen which is the main female’s hormone that is responsible for protecting against memory losses and normal mental functioning as compared to normal age. When a female gets older, the drop of estrogen level takes place after menopause and that could explain the higher risk of AD for older women than for men. From the other side, some of testosterone, male hormone, converts into estrogen and that could protect men. People that have a family history of the disease are above the average risk level for AD. Researchers have found that ApoE4 gene could be responsible for late and early onset cases. Some studies discovered that African Americans and Hispanics are at higher risk than Caucasian Americans, AD happens less often in Native Americans Crees and Cherokees and in Asians than in regular American population. Genes may have dissimilar effects in different populations (Tanzi and Ann B. 2000).
High blood pressure and high cholesterol levels can be in fact even more risky than ApoE4. At a very high risk are also people that inherit the Down syndrome. Some other risk factors are: 1) lower education and economic groups, 2) small head size, 3) Depression, 4) head injury.
A very dangerous thing about AD is that brain is being damaged for years before even the symptoms appear. The early symptoms that appear might be so mild that people could hardly notice them. The first one could be forgetfulness. People with AD may have troubles with recalling names of people that they know or remember latest events or solve simple math problems. As the disease progresses people may face
• Unreasonable weight losses
• Incontinence
• Changes in sexuality
• Difficulties in walking
• Depression, apathy, irritability
Half of all patients that have AD face the psychotic problems that can include hallucinations, visions. It is a complex form of the disease that is probably based in the genetic level. Many other medical conditions have similar to Alzheimer’s symptoms. It is crucially important to identify the right disease to succeed in future treatments of it. However, we have not yet developed a test that would diagnose AD with the hundred percent guarantee. So, right now diagnosis involves ruling out other disorders the following questions about the state of a patient:
• Do psychologist tests indicate dementia?
• Does the patient have problems with using language, walking, perception?
• Has memory gotten greatly worse?
• Is the patient over 40?
• Does his/her behavior changes daily?
• Does the patient have a family history of AD?
• Are there other symptoms like depression, weight loss, hallucinations?
Other steps that are involved in making a decision involve laboratory tests (EEG and tests to rule out other diseases) and psychological testing to determine the presence of dementia.
There is no guarantee that some life styles will prevent AD, however, studies show that particular life styles can play very important role in preventing AD. It is crucial to prevent heart diseases. Calcium – Channel Blocker and other Anti – Hypertensive Agents can be used to protect the heart and consequently the brain. Statins which are the common drugs to lower the cholesterol level can also be used to lower the risk for AD. Another method that is used to prevent AD is the Hormone Replacement Therapy. Because of the difference in AD rates among different populations, researches are looking at dietary factors as a protection. In China and Nigeria where fat consumption is much lower than in the U.S. the risk for AD at the age of sixty five is only 1% compared to 5% in the U.S. Studies in Netherlands reported the relationship between dementia and cholesterol levels. Eating a lot of dark colored fruits and vegetables may slow the brain degradation. Blueberries are found to be the most helpful. In any case dark colored fruits and vegetables are good for health. Other studies showed that soy has estrogen which is thought to protect the memory. Some reported that small consumption of alcohol can be effective in stopping the brain aging. Not everybody agrees though. Caffeine has a good effect on women in terms of mental functioning. Much research on AD has showed that oxidation may have an impact in the disease process. Vitamin E may protect from mental decline. Other health behaviors like aerobic exercises or jogging are important in stopping the mental decline. The more person exercise the better. Another aspects that play role in the prevention of mental decline is lifelong learning and stress reduction.
Unfortunately, today we can only try to prevent AD and have no cures. However, there are drugs under investigation that are aimed to slow the progression of the AD. The bad thing is that improvements from some of these drugs can so little that a patient or his/her family would not even notice. The good thing is that even these drugs will help to postpone the necessity of taking a patient to a nursing home (Alzheimer’s Association). The only agents that are approved called selective Acetylcholinesterase inhibitors. They are designed to protect the cholinergic system which is responsible for memory and learning and is destroyed in AD. We have the following:
• Donepezil. Donepezil (Aricept) is taken once a day and has only modest benefits but it helps to slow loss of function and reduce caregiver burden. It works equally in patients with or without ApoE4. It may even have some advantage for patients with moderate to severe Alzheimer’s disease.
• Rivastigmine. Rivastigmine (Exelon) targets two enzymes (the major one, acetylcholinesterase, and butyrylcholinesterase). It is taken twice a day. This agent may be particularly beneficial for patients with rapidly progressing disease. This drug has slowed or slightly improved disease status even in patients with advanced disease. (Rivastigmine may cause significantly more side effects than donepezil, including nausea, vomiting, and headache.) As with all anticholinergics, the drug is not a cure.
• Galantamine (Reminyl). Galantamine not only protects the cholinergic system but also acts on nicotine receptors, which are also depleted during Alzheimer’s Studies report that it improves daily living, behavior, and mental functioning, including in patients with mild to advanced−moderate Alzheimer’s disease and those with a mix of Alzheimer’s disease and vascular dementia. Some studies have suggested that the effects of galantamine may persist for a year or longer and even strengthen over time.
• Tacrine. Tacrine (Cognex) was the first cholinergic protective drug. It needs to be taken four times a day, has only modest benefits, and has no benefits for patients who carry the ApoE4 gene. In high doses, it can also injure the liver. In general, newer cholinergic protective drugs that do not pose as great a risk for the liver are now used for Alzheimer’s (Castleman, Gallagher-Thompson, and Naythons 2000).
Half of the patients that have mild to moderate disease show sight improvement. Latest studies, however, show little difference in effectiveness among them. All these drugs have gastrointestinal side effects, including nausea. Anyway, these drugs still have some effect. Some researchers found that some patient could have no reactions to one particular drug, in this case the drug should be switched and there is actually a chance that it will work. There are also some alternative treatments that are being studied right now. One of them is Gingko Biloba. It is a common herb that increases blood flow to the brain. Its extract Egb 761 may slightly improve the memory of patients that have mild to moderate AD. Gingko Biloba has only minimal side effects. Turmeric also has properties that may protect from AD. Turmeric is a spice that has curcumin as one of its components which is thought to protect from AD. Studies have also found that melatonin, the natural hormone that has to do with sleep regulation, could break down beta amyloid, and it is able to pass through the blood – brain barrier. Studies reported that melatonin improves the sleep, and in some cases even slows the mental regression (H. Simon).
A number of other medical treatments are being investigated and show promise in early or late trials. Researches are focusing on agents that can prevent the build-up of beta amyloid, its toxic effects on nerve cells, or other mechanisms of the disease process. Among them are the following:
• N−methyl−D−aspartate (NMDA) blockers. NMDA blockers, such as memantine (Ebixa), bind to glutamate, an amino acid that excites nerves and, in excess, is a powerful nerve−cell killer. Memantine has shown some to be somewhat effective in improving symptoms and is being considered for approval in Europe and the US.
• Growth factors that stimulate nerve activity in the brain. Cerebrolysin (Cere) is an example of such drugs and is showing promise in clinical trials in improving mental function and other symptoms, with sustained effects even after the drug has been stopped. Leteprinim potassium (Neotrofin) activates genes that produce nerve−growth factor in the brain. Early human trials are suggesting that it may have positive effects on memory and behavior. Insulin and insulin growth factors may prevent beta amyloid accumulation.
• Antioxidants. Indole−3−propionic acid, or IPA (Oxigon), is a natural agent that may interfere with enzymes that contribute to the Alzheimer’s disease process.
• Huperzine alpha, another acetylcholinesterase inhibitor, improved mental function, behavior, and mood in Alzheimer’s disease patients in one Chinese study. Other research also suggests some benefits.
• Piracetam is a nerve protective agent called a nootropic. It has undergone a number of small studies, with few significant results. More research is needed to determine any benefits.
• Researchers are investigating immunotherapies that include vaccines, which use molecules in beta amyloid as targets for the body’s immune system, and antibodies that block proteins called CD40−CD40L, which are involved in amyloid deposition.
• Tetracyclines. Antibiotics known as tetracyclines, such as tetracycline itself, doxycycline, and minocycline, have anti−inflammatory properties that are now being investigated in a number of chronic inflammatory conditions (such as periodontal disease). They also may have activity against beta amyloid in the brain (H. Simon).
The worst thing about Alzheimer’s disease is that it is not fully investigated yet. None of the doctors can surely diagnose it. And what is even worse none can cure it. The worst thing is that AD lethal in all case. Using all the treatments that have been or are still being studied can only postpone the need for the nursing home (Terry, Katzman, Bick, Sisodia 1999).
The issue of Alzheimer’s disease is crucially important to me and should be to everyone. Mainly, because nobody is insured from getting AD and there is no certain way to escape it. Our modern medicine has been developing through ages and now it cures many dangerous diseases; however, it is simply helpless against the Alzheimer’s. If scholars completely investigate AD it will help to understand the brain and its impact on people’s behavior. Using that knowledge it would be possible to impact the brain and its functions. Unfortunately, all the studies that were conducted about AD and were presented above can not state something about AD with a hundred percent certainty. All the medications that are listed above do not stop AD; they can even hardly slow it. It is very unpleasing fact that mankind has greatly developed ways to make the brain progress but have not yet found any way to stop the regression of the brain.
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