New evidence is suggesting an existing generic drug could prevent the development of Alzheimer’s disease — but only if a person takes the medication long before symptoms of Alzheimer’s take hold.

Alzheimer’s Disease

Alzheimer’s disease is the most common form of dementia.  According to the Centers for Disease Control and Prevention (CDC), approximately 5.7 million adults in the United States live with this condition.  Today there is no known cure for Alzheimer’s.  Following the onset of Alzheimer’s symptoms tend to worsen progressively.

Alzheimer’s Prevention

Consequently, the question, “Can specialists prevent the disease in people deemed at increased risk?” is quite important.  The authors of a new study, from the University of Virginia in Charlottesville, are seeking to answer just this question.  Their recent research suggests that memantine – an available generic drug currently used to manage Alzheimer’s symptoms – may help prevent the disease.  The preventative effect of memantine, might only happen if a person takes the drug before the symptoms of Alzehiemer’s set in.  “Based on what we’ve learned so far, it is my opinion that we will never be able to cure Alzheimer’s disease by treating patients once they become symptomatic,” says Prof. George Bloom, of the University of Virginia, who oversaw the study.  “The best hope for conquering this disease is to first recognize patients who are at risk, and begin treating them preventatively with new drugs and perhaps lifestyle adjustments that would reduce the rate at which the silent phase of the disease progresses,” he says, adding, “Ideally, we would prevent it from starting in the first place.”

The journal Alzheimer’s & Dementia has now published the team’s findings.

The Science

The researchers explain that Alzheimer’s disease actually begins up to a decade before symptoms start to show.  One key characteristic of Alzheimer’s is that, once affected by the disease, brain cells attempt to divide — possibly in order to balance out the death of other brain cells — only to die, anyway.  In any case, this division of brain cells is unusual and does not happen in a healthy brain. The attempt at cell division is called the “cell cycle re-entry process.  The researchers note that as much as 90 percent of brain cell death that occurs in the Alzheimer’s brain follows this cell cycle re-entry process.  Once a patient has severe Alzheimer’s they will have lost about 30 percent of the neurons in the frontal lobes of the brain (the part of the brain that controls behavior, learning, personality, and voluntary movement).

Study co-author Erin Kodis has developed a hypothesis about what triggers this unusual cell division.  She believes that excess calcium enters brain cells through special receptors called NMDA receptors. This drives brain cells to start dividing.  Kodis confirmed that her hypothesis was correct. This excess calcium seems to be related to the formation of the brain plaques that are characteristic of Alzheimer’s disease.

How does Memantine work?

Kodis saw that NMDA receptors on brain cells, in the early stages of Alzheimer’s before plaque buildup starts, open to receive the excess calcium that ultimately leads to their destruction.  But then Kodis made another discovery: the drug memantine prevented cell cycle re-entry by closing the NMDA receptors on the surface of neurons.  Kodis’s experiments suggest that memantine might have potent disease-modifying properties if it could be administered to patients long before they have become symptomatic and diagnosed with Alzheimer’s disease.  These findings are particularly promising as memantine has few known side effects, and those that have been reported are rare and do not have a major impact on an individual’s well-being. In addition, memantine is already generic and relatively inexpensive.

In the future, if this research continues down this positive path a preventive approach might be to screen people for Alzheimer’s risk as early as possible.  Then those patients found to be at high risk could be prescribed drugs like memantine.  Alzheimer’s could become a chronic disease like hypertension, allowing people to live full lives.  Currently, Bloom and his colleagues are planning a clinical trial to test the preventive strategy that they outlined in the study.

Fingers crossed.