Alzheimer's patients have a molecular blockade that could be potentially broken to reverse the disease after researchers showed Wednesday that removing the blockade improved cognition in mice with Alzheimer's-like disease.

Researchers injected mice with a molecule that stops overproduction of a protein called HDAC2. High levels of HDAC2 are found in Alzheimer's patients and overexpression of the HDAC2 gene causes Alzheimer's-like symptoms in mice.

The mice regained their cognitive abilities when researchers reduced the buildup of the protein, suggestive that neurodegenerative conditions such as Alzheimer's are reversible.

Researchers warned that any drug is at least five to 10 years away from human trials and would only treat the symptoms of Alzheimer's, not the root cause. However, the researchers said simply proving the disease is potentially reversible is a huge step forward.

If your memory is everything that you know written in a book, then in order to have access, you have to open the book and to turn the pages, Johannes Graff, lead researcher and a postdoctoral researcher at Massachusetts Institute of Technology, told HealthDay. Buildup of the protein makes the pages inaccessible, Graff said.

We are proposing to reopen the book and allow it to be more easily read, Graff told HealthDay.

Nature published the study online Wednesday.

Alzheimer's is the most common form of dementia in the United States, affecting more than 5 million people, according to the Centers for Disease Control and Prevention. The number of people who suffer from the disease is expected to double every 20 years.

Symptoms of Alzheimer's include memory loss, confusion, difficulty completing familiar tasks, decreased judgment and problems speaking or writing.

Healthcare costs related to Alzheimer's disease totaled almost $8 billion in 2010, according to the Alzheimer's Association, a nonprofit organization that advocates for Alzheimer's patients in the federal and state governments.

There is as yet no cure or successful treatment for Alzheimer's disease. The Obama administration set a goal of 2025 to find an effective treatment and pledged to spend an additional $50 million on dementia research on top of the $450 million the government spends annually until a treatment is found.