Researchers have now found an important factor that determines how Alzheimer's disease progresses.

Researchers from the University of Florida used mice models to understand how the disease develops. It is known that a kind of lesion triggers the formation of another lesion that leads to the progression of the disease.

According to National Institute on Aging, Alzheimer's disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills and, eventually even the ability to carry out the simplest tasks of daily living. In most people with Alzheimer's, symptoms first appear after the age 60.

The first kind of lesion is due to the incorrect folding of a protein and is called amyloid plaque. But, the presence of this lesion doesn't lead to the progression of the disease. People who have Alzheimer's disease have the second type of lesion that's called neurofibrillary tangle.

"Understanding how this sequence of events works is thought to be critical and could lead to new therapeutic approaches," said Borchelt, director of the SantaFe HealthCare Alzheimer's Disease Research Center at UF and the McKnight Brain Institute.

Proteins are complex structures that need to be properly folded to carry out a function. Cells spend a lot of energy getting the proteins folded the right way and removing all incorrectly folded proteins. The latest study shows that the amyloid plaques interfere with the cell's ability to maintain the proper structure of the proteins.  

"This deficiency in cell function could set the stage for allowing the formation of the neurofibrillary tangles that seem to be the key pathology to symptoms," Borchelt added in a news release.

The tangles in the brain are a result of a protein folding incorrectly and forming clumps with other tau proteins. Many pharmaceutical companies are now trying to find drugs that could stop this incorrect folding of proteins in the brain. Researchers in the present study say that more research is required to understand how these tangles affect the disease progression.

The study is published in the journal Human Molecular Genetics.

According to Alzheimer's disease Facts and Figures, an estimated 5.4 million people have Alzheimer's disease, meaning that one out of every eight older Americans suffers from the condition.