Scientists at Berlex Pharmaceuticals, the US subsidiary of Germany's Schering, have identified a biologic marker for Alzheimer's disease that could provide a simple diagnostic for the condition and allow its progression to be monitored.
They have found a receptor called CCR1 - usually found on white blood cells - is also present in the brains of patients with Alzheimer's. The protein is not normally seen in healthy brain tissue, and increasing concentrations appear to correlate with the advancement of the disease.
"Our research has demonstrated that CCR1 is evident in the brains of patients very early in the disease process, even in patients with mild cognitive impairment," said Meredith Halks-Miller, head of pharmacopathology at Berlex and the study's lead investigator.
This suggests that a test to detect CCR1 in the central nervous system could be used to develop a radioimaging test that would detect Alzheimer's at an early stage and allow treatment to be initiated promptly. It would also be a valuable tool for the development of new drugs to treat the disease.
The researchers report that CCR1 is present in swollen nerve fibres that are associated with a molecule called amyloid beta 1-42 (Abeta42), a peptide that accumulates and creates the senile plaques that are one of the characteristic hallmarks of Alzheimer's. As the disease progresses, the number of abnormal CCR1-containing neuronal fibres also increases.
Schering has initiated a clinical study to determine if targeting CCR1 with a radiolabelled, small molecule CCR1-antagonist - called BX471 - has potential as a brain-imaging biomarker. The Phase I/II study, which will validate the safety and utility of the diagnostic agent, is being conducted at the University of Dresden in Germany. Preliminary results of the study should be available in 2004.
The findings are due to be published in the November issue of the Annals of Neurology.