Old Drugs, New Tricks
Cholesterol and cancer drugs may fight Alzheimer's

Context: Often a drug that treats one disease works for another, apparently unrelated disease. Two early antidepressants began their careers as an antibiotic (iproniazid) and an antihistamine (imipramine). The impotence drug Viagra was designed to prevent heart failure. Now, two recent papers report that drugs already on the market may help prevent Alz­heimer's disease.

Methods and Results: Some studies have found that patients taking statins, a class of cholesterol-lowering drugs, are less likely to develop Alzheimer's disease. A team led by Sam Gandy at the Farber Institute for Neurosciences at Thomas Jefferson University in Philadelphia sought an explanation of this finding. It turns out that when statins are added to cultures of neurons, the neurons more quickly destroy a precursor of the protein amyloid that goes on to form the plaques characteristic of Alz­heimer's. To determine exactly what statins do in neurons, Gandy's team both blocked and mimicked their effects by manipulating proteins—and so showed which proteins the statins affect.