In Alzheimer's disease, a degenerative neurological disorder associated with memory loss, plaque forms in the hippocampus, the brain's main center for the storage of sensory information for the short term and the formation of long-term memories. In the early stages, Alzheimer's disease affects declarative memory, the ability to remember past events and facts. In later stages, it also induces memory scramble, a condition where old memories are interpreted as recent ones. There are a variety of treatments that may alleviate memory loss symptoms in Alzheimer's.
Acetylcholine Agonists
Several acetylcholine agonists are FDA-approved for the treatment of Alzheimer's, including galantamine, tacrine, rivastigmine and donepezil. This class of drugs increases the available amounts of the neurotransmitter acetylcholine in the brain. As reported by a study published in the November 2006 issue of "Neurobiology of Learning and Memory," Alzheimer's disease is significantly correlated with a breakdown of acetylcholine, which causes cell death via the glutamate pathway. As acetylcholine stimulants raise the brain's levels of acetylcholine, this class of drugs may have a positive effect on the memory decline found in Alzheimer's.
Selective Serotonine Reuptake Inhibitors
Selective serotonin reuptake inhibitors, or SSRIs, are primarily prescribed for major depression and generalized anxiety disorder. They work by preventing the serotonin transporter from transporting serotonin back into the brain's neurons. Serotonin down-regulates fear processing in the amygdala, and the secretion of adrenaline and noradrenaline from the adrenal glands. Down-regulation of these chemicals can alleviate symptoms of depression and anxiety.
According to a study published in the February 2010 issue of "Archives of General Psychiatry," SSRIs also have positive effects on the memory and cognition. The researchers found that SSRIs assist in generating new neurons. As the main cause of memory loss is a breakdown of neurons in the hippocampus, SSRIs may be able to halt the progression of memory loss in Alzheimer's.
Statins
Statins are a range of cholesterol-lowering drugs. They block an enzyme crucial to the production of the "bad" cholesterol known as low-densitity lipoprotein, or LDL, cholesterol. Blocking this enzyme inhibits the synthesis of LDL cholesterol, and promotes the generation of cholesterol receptors which can help to remove cholesterol from the blood.
According to a study published in the July 2008 issue of "Neurology," statins may halt the progression of Alzheimer's, but the results are controversial. Other studies have shown evidence of a direct correlation between statins and memory loss.
Vaccines
One of the newest potential treatments of Alzheimer's is a vaccine that cleans out the plaques from the hippocampus, reports researchers in the April 2008 issue of "Journal of Neuroscience." The vaccine contains the beta-amyloid protein that causes plaque formations. The protein available in the vaccine stimulates the immune system to produce antibodies that attack the plaque formations in the hippocampus. Though the vaccine cannot reverse cell damage that has already occurred, it can slow down the progression of the disease. As of August 2010, the treatment still needs to be tested in humans.
Vitamin E
High doses of alpha-tocopherol, or vitamin E, may slow down the progression of Alzheimer's, report researchers from the VA Bedford Medical Center, Massachusetts General Hospital and Harvard Medical School. The researchers compared the cognitive function of 208 Alzheimer's patients to a control group over three years and found that the debilitating disease progressed slower in patients who took vitamin E. The findings were presented at the 2009 meeting of The American Geriatrics Society.
References
- "Neurobiology of Learning and Memory"; Rapid Induction of Specific Associative Behavioral Memory By Stimulation of the Nucleus Basalis in the Rat; Miasnikov, et al.; November 2006
- "Archives of General Psychiatry"; Escitalopram and Enhancement of Cognitive Recovery Following Stroke; Ricardo E. Jorge; February 2010
- "Neurology"; Use of Statins and Incidence of Dementia and Cognitive Impairment Without Dementia in a Cohort Study; C. Cramer, et al.; July 2008
- "Journal of Neuroscience"; A Two-Year Study with Fibrillar β-Amyloid (Aβ) Immunization in Aged Canines: Effects on Cognitive Function and Brain Aβ; Elizabeth Head, et al.; April 2008
- Reuters: Vitamin E May Slow Alzheimer's Disease
