Research led by New York University Grossman School of Medicine and the Institute of Medical Biochemistry Leopoldo de Meis in Brazil has identified two biomarkers in the blood that decrease as cognitive decline and Alzheimer’s disease progresses.
The researchers found that the protein acetyl-L-carnitine was reduced in both men and women with mild cognitive impairment or early-stage Alzheimer’s and that free carnitine, a byproduct of acetyl-L-carnitine was reduced in women but not men with these conditions.
If validated, these findings could lead to an early blood test for the disease. “A major challenge in the development of more effective therapeutic strategies for Alzheimer’s disease is the identification of molecular mechanisms linked to specific pathophysiological features of the disease,” explain co-lead authors Mychael Lourenco, PhD, Institute of Medical Biochemistry Leopoldo de Meis, and Carla Nasca, PhD, New York University Grossman School of Medicine, in the journal Molecular Psychiatry.
A long phase of amnestic mild-cognitive impairment, essentially an early stage of Alzheimer’s, can be difficult to identify in those affected. If distinctive diagnostic biomarkers can be reliably identified and tested for using a simple blood test this would be a big step forward to help clinicians treat this difficult condition at an early stage.
In this study, 125 individuals from two independent study groups in the U.S. and Brazil were included to assess levels of acetyl-L-carnitine and free-carnitine. The biomarkers had previously been identified as being linked to neurodegenerative disease in a rodent model. In the two groups, some individuals had amnestic mild-cognitive impairment and some more advanced cognitive impairment and Alzheimer’s disease.
The researchers found that acetyl-L-carnitine levels were reduced in correlation with the level of cognitive impairment of those tested with the lowest levels seen in those with the most advanced disease. This also seemed to correlate with the level of amyloid beta and tau tangles seen in the brains of these individuals. Notably, the same correlation was seen with free carnitine in women in the study, but not men.
“Our findings offer the strongest evidence to date that decreased blood levels of acetyl-L-carnitine and free carnitine could act as blood biomarkers for identifying those who have Alzheimer’s disease, and potentially those who are at greater risk of developing early dementia,” said first author Betty Bigio, PhD, New York University Grossman School of Medicine, in a press statement.
“The results also might explain the differences by sex in Alzheimer’s disease, with more women than men having dementia,” she added.
The research is early and needs further validation, but the investigators think it could lead to a blood test to diagnose and follow the progression of Alzheimer’s disease. They also now want to do more research into how acetyl-L-carnitine is linked with cognitive decline and Alzheimer’s disease.
