Preventing Alzheimers

The Search for AD Prevention Strategies continued...

Examining nonsteroidal anti-inflammatory drugs (NSAIDs). Inflammation of tissues in the brain is a common feature of AD, but it is not clear whether it is a cause or effect of the disease.
Some population studies suggest an association between a reduced risk of AD and commonly used NSAIDs, such as ibuprofen, naproxen, and indomethacin.

Clinical trials thus far have not demonstrated a benefit for AD from these drugs or from the newer cyclooxygenase-2 (COX-2) inhibitors, such as rofecoxib and celecoxib. A trial testing whether
naproxen or celecoxib could prevent AD in healthy older people at risk of the disease has been halted, but investigators are continuing to conduct follow-up examinations with participants and to examine data about cognitive changes and possible cardiovascular risk. Scientists continue to look for ways to test how antiinflammatory drugs targeting particular pathways might affect the development or progression of AD.

Learning about antioxidants and other interventions. Another promising area of research focuses on highly active molecules called free radicals. Damage from these free radicals during aging can build up in nerve cells and result in a loss of cell function, which could contribute to AD. Some population and laboratory
studies suggest that antioxidants from dietary supplements or food may provide some protection against this damage (called oxidative damage), but other studies show no effect.

Clinical trials may provide some answers. Several trials are investigating whether two antioxidants¡ªvitamins E and C¡ªcan slow cognitive decline and development of AD in healthy older individuals. The NIA is conducting a clinical trial that will examine whether taking vitamin E and/or selenium supplements over a period of 7 to 12 years can help prevent memory loss and dementia. This trial has been added on to a prostate cancer prevention
clinical trial funded by the National Cancer Institute. The NIA is also conducting a clinical trial to determine whether antioxidant supplements can prevent cognitive decline in healthy older women or older women at increased risk of dementia.

Another just-completed study focused on the use of vitamin E supplements in people with MCI. This NIA study, the Memory Impairment Study, compared donepezil (Aricept), vitamin E
supplements, or placebo (an inactive substance) in participants with MCI to see whether the drugs might delay or prevent progression to AD. The study found that taking the vitamin E had no effect on progression to AD at any time in the study when compared with placebo. It may be that this antioxidant may not help after memory declines have already started. Donepezil, however, did seem to delay progression to AD over the first year of treatment. Interestingly, there seemed to be an interaction between the genetic makeup of
participants and their response to treatment: People carrying the risk factor APOE e4 allele delayed the risk of developing AD for the 3 years of the trial. Scientists caution, however, that people with MCI should not be tested to see whether they carry the APOE-e4 allele because more research is still needed to understand how the drug works in the body and to answer other questions.

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