Boffins look to diagnose Alzheimer's earlier

Using one of the latest advances in sub-atomic technology, scientists at Lancaster University have developed a technique which could potentially allow the early diagnosis of diseases such as Alzheimer's and Parkinson's.

By the time such diseases are diagnosed conventionally, significant brain damage has already occurred. But more advanced drug treatments are likely to be increasingly effective if the disease can be diagnosed earlier.

The breakthrough technique also allows scientists to monitor the effectiveness of drugs and other inhibitors on the aggregation of key proteins that accumulate in the brain in Alzheimer's and related disorders.

The process involves monitoring protein aggregation in vitro and is non-invasive. It can generate results rapidly, potentially speeding up the drug discovery process. The research was partly funded by the Alzheimer's Society.

Central to the success of the breakthrough was protein measuring equipment from UK company Farfield Scientific. This uses a laser-based technology known as dual polarisation interferometry to detect and study the structure and aggregation of disease-related proteins.

Using Fairfield's equipment, the researchers at Lancaster University can precisely measure in vitro the protein interactions that lead to aggregation in real time.

"The technique can be used to gain a better understanding of many diseases at a molecular level," said Professor David Allsop of Lancaster University.

"This is done by measuring protein structures as they interact with each other, with other proteins or with candidate drug molecules."

The technique can detect these interactions at a very early stage, when aggregation of proteins is thought to be most toxic to brain cells and which leads to the rapid progress of the disease.

The Farfield equipment is capable of recording changes smaller than 0.1 angstroms (one hundredth of a nanometre or 0.00000001mm) which is considerably smaller than the protein molecules.

Proteins are very large complex molecules that can fold into a variety of different shapes. This 3D shape is extremely important and can radically affect the protein's properties.

Misfolded proteins are also the source of prion-based diseases, the suspected infective agent for diseases such as BSE in cows and Creutzfeldt-Jakob disease in humans.

How these 'rogue' proteins behave at a molecular level is a key to understanding the mechanisms of these diseases.

This dual polarisation interferometry technique behind the breakthrough uses the principle of optical interference, where two light sources are made to interact (or interfere) with each other to produce a 'fringe' pattern demonstrating the wave-like nature of light.

The Farfield system employs two waveguides with a laser light source. A waveguide is an optical structure that guides light.

The changes in the behaviour of light passing through the device enable parameters such as the size, density and mass of molecules attached to the sample surface to be determined extremely accurately.