Novo-Nordisk makes the FlexPen, a pre-filled insulin delivery device that eliminates the step of loading insulin into the delivery system.
Neuroscientist William Klein of Northwestern University in Chicago says that insulin helps the brain break down waste that interferes with its ability to function. One bit of junk can be especially troubling - a tiny, soluble molecule he describes as a precursor to amyloid beta, a protein fragment and the notorious sticky building-block of brain plaques.
According to Dr. Klein, these molecules, known as A-beta derived diffusible ligands and called ADDLs for short, float around the brain and gum up insulin receptors. When the brain has enough insulin, they disappear before they can stick to nerve cells and cause damage. But when it doesn't - as in some aging brains, for example - the shortage triggers a vicious circle: ADDLs build up, insulin levels decline further, more ADDLs stick around, even less insulin is produced. "Then," says Dr. Klein, "the brain can't stop the next round of ADDLs." Eventually, these molecules clump together to form plaque.
To develop treatments that preserve insulin in the brain, Dr. Klein and his colleagues formed a biotech company, which has licensed an antibody to fight ADDLs that pharmaceutical giant Merck is now testing.
But nothing is straightforward. Dr. Klein also says that not everyone develops ADDLs as they age - and, in some cases, the plaques play a protective role because the dangerous precursor molecules stick to them instead of damaging nerve cells. This, he says, explains why some people with plaques suffer from no dementia at all.
Yet not all ADDLs stick to plaques, and the more that drift freely, the more they can damage brain cells, suggesting that all people with plaques would develop Alzheimer's if they live long enough.
Meanwhile, research from the University of California at Irvine suggests that ADDLs look a lot like prions, the mysterious molecules linked to such deadly afflictions as bovine spongiform encephalopathy, or "mad cow disease."