On 21 January, a large group of scientists published findings on a new potential marker of disease progression for people with early-onset Alzheimer’s disease (AD) in the journal Nature medicine. Previous research showed that a blood test for the protein neurofilament light chain (NfL) might be a useful marker of disease progression in different diseases of the brain. Since research on AD is focusing more and more on accurate ways to predict disease progression, the team looked at potentials in using this relatively novel technique in AD as well.
The researchers included samples from 405 people who participated in the Dominantly Inherited Alzheimer Network study. This study involves people who carry one of the gene mutations (Presenilin1, Presenilin2 or APP) that are known to cause “dominantly inherited AD” which is also referred to as “familial Alzheimer’s disease”. Looking at different factors, the scientists found that on one hand the levels of NfL in the fluid of the spinal cord (using 187 samples) and the serum in the blood (using 405 samples) corresponded to each other. This is especially interesting since many patients and research participants consider the extraction of spinal cord fluid much more unpleasant than the collection of blood. Furthermore, results showed that NfL levels of people with familial AD are elevated in stages before symptoms appear.
Further analyses following up on the same participants (196) showed that the rate of NfL in the serum also peaked in those who developed symptoms over time and that this came along with “cortical thinning”, a thinning of the brains outer layer (monitored with a brain imaging technique). The team also reported that they were able to predict the rate of cortical thinning as well as changes in thinking performance (assessed with a pen and paper test) based on the measured NfL rate in the serum. Based on these results, the researchers concluded that measuring NfL dynamics in the serum might be useful as a clinical biomarker, although noting that further research is needed to determine if this research can also be translated to other forms of AD such as sporadic AD.
