Study: Nicotine increases brain tangles in Alzheimer's disease

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Nicotine does not help Alzheimer's disease, a new study shows.

While earlier research suggested nicotine decreases the brain plaque associated with the disease, a new mouse study found that nicotine actually increases fibrous brain tangles, another sign of the disease.

"It is possible that nicotine might have a beneficial effect on plaque but a worsening effect on the tangles, so you would essentially convert the disease from one form to another," a lead researcher said. Findings are reported in last week's issue of the Proceedings of the National Academy of Sciences.

Two different pathologies are at work in the brain in Alzheimer's. These are amyloid plaques caused by beta-amyloid protein deposits and neurofibrillary tangles containing clumps of altered tau proteins.

Researchers wanted to see if nicotine had a beneficial effect on both plaque and tangle accumulation. The researchers gave nicotine to mice genetically engineered to develop both of these neurological markers of Alzheimer's disease. Nicotine increased the effect of altered tau proteins, causing brain tangles to develop sooner.