A connection between Neurofilament light (NfL) levels present in the blood and Alzheimers disease was recently made in a study released by the JAMA Network. This discovery could lead to a simple blood test that has the ability to detect the levels of conditions associated with cognitive impairment.  This early testing is an incredible breakthrough because, for starters, to be forewarned is to be forearmed. 

The study 

Nikalas Mattsson, MD, PhD, of Lund University in Sweden, led his colleagues in a cohort study of 1,583 individuals in the multicenter Alzheimers Disease Neuroimaging Initiative study from September 2005 through June 2016. Of the total individuals studied, 45% were women with a mean age of about 73. No cognitive impairment was evident in 401 people (control group), 855 showed mild cognitive impairment, while 327 were exhibiting dementia due to Alzheimers disease. As reported in JAMA Neurology, Longitudinal NfL levels were linked to baseline cerebrospinal fluid (CSF) biomarkers, MRI measures, PET imaging, and poor cognitive performance among Alzheimers Disease Neuroimaging Initiative Study (ADNI) participants. We could detect significant longitudinal changes in plasma NfL and these correlated with other changes related to Alzheimers disease, Mattsson reported. 

Back up. What are Neurofilament light (NfL) levels? 

When brain neurons are damaged or dying, they release NfL protein that leaks into the cerebral spinal fluid (CSF) and blood. Rising levels of NfL in CSF signal neuron loss that has occurred in stroke, traumatic brain injury, Alzheimers disease, multiple sclerosis, and other neurologic conditions. 

NfL levels in the final report 

In this study, baseline mean NfL levels were higher in patients with mild cognitive impairment (37.9 ng/L) and Alzheimers dementia (45.9 ng/L) than in the control group that was cognitively unimpaired (32.1 ng/L). Serum NfL levels increased significantly in all groups, but rates were greatest among patients with Alzheimers dementia.  

Overall, faster increases in NfL levels correlated with faster increases in CSF biomarkers of neuronal injury. This resulted in increased rates of cerebral atrophy and hypometabolism, and faster worsening in overall cognition. 

Promising Biomarker 

In the instance of studying Alzheimers disease, biomarkers are a measurable substance whose presence indicates a worsening of cognition.  Blood-based biomarkers like NfL can make it possible to detect and monitor biological changes in Alzheimers disease with non-invasive methods, Mattsson explains. New evidence indicates that blood-based FfL levels may be a promising biomarker of Alzheimers disease neurodegeneration.  

For example, in a study reported by MedToday that examined individuals with a rare form of familial Alzheimers disease, serum NfL predicted disease progression and brain neurodegeneration at very early stages, before symptoms even began to develop.  

Non-Invasive Testing Methods 

Blood-based biomarkers like NfL can make it possible to detect and monitor biological changes in Alzheimers disease with non-invasive methods, Mattsson noted. In the future, this test may be used together with plasma measures of beta-amyloid and tau for a comprehensive work-up of Alzheimers disease and other dementias, he reported to MedPage Today.   

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