Sleep deprivation linked to Alzheimer’s

Chronic lack of sleep may promote the development of Alzheimer's disease. Researchers monitored the levels of amyloid beta, a protein fragment linked to the disease, in the brains of sleep-deprived mice with symptoms of Alzheimer's.

They found that preventing the mice from sleeping caused a 25 per cent increase in levels of the peptide, which builds up in the brains of Alzheimer's sufferers to form damaging plaques.

Amyloid beta levels were generally higher when mice were active and those that stayed awake longer had higher amounts. Separate research linked the finding to human beings, showing amyloid beta levels in the spinal fluid of volunteers increased when they were awake and lowered during sleep.

Professor David Holtzman, from the Barnes-Jewish Hospital in St Louis, Missouri, where both studies were carried out, said: "The results suggest that we may need to prioritise treating sleep disorders."

The scientists also found a link with orexin, a protein involved in regulating the sleep cycle. When it was injected into the brains of mice, they stayed awake longer and their amyloid beta levels increased. A drug that blocked orexin's action led to a reduction in amyloid beta levels and caused mice to be awake less.

Professor Holtzman's research is published today in the journal Science.