Scientists Identify Toxicity Mechanism for Lewy Bodies

People with Lewy body disease and Parkinson's disease have Lewy bodies in the cells of their brain. (Lewy bodies are microscopic protein deposits found in deteriorating nerve cells.) The presence of Lewy bodies suggests underlying problems in protein recycling and waste disposal, but it was not known how disrupting those processes kills brain cells. Researchers at Emory University School of Medicine have now discovered what could be an important pathway for controlling cell loss and survival.

The main component of Lewy bodies is a protein called alpha-synuclein. An accumulation of alpha-synuclein is toxic to cells. The researchers have now found that alpha-synuclein disrupts a cell survival circuit known as MEF2D. An accumulation of alpha-synuclein interferes with the cell's recycling of MEF2D, leading to cell death.

The hope is that further research could identify drugs to regulate MEF2D, allowing brain cells to survive toxic stresses that impair protein recycling.

For more information, see the press release about this research. The research was published in Science on January 2, 2009; see the abstract online.

Sleep Disorder May Indicate Dementia Risk

As we reported previously, people with a kind of extreme sleep disorder have a high risk of developing LBD or Parkinson's disease. A new study has supported the relationship. The sleep disorder is called REM sleep behavior disorder. People with the disorder do not have the normal lack of muscle tone that occurs during REM sleep (the dream stage of sleep). Instead, they punch, kick, or cry out, essentially acting out their dreams.

The study followed 93 people with this type of sleep disorder who had no signs of a neurodegenerative disease, such as dementia or Parkinson's disease. Within five years, 26 of the people developed a neurodegenerative disease.

For more information, see the press release. The research was published in Neurology on December 24, 2008; see the abstract online.