Alzheimer’s disease, a condition affecting over six million Americans—most of them women—progressively erodes memory, thinking, and daily functioning. Now, a groundbreaking study offers new insights into why women may be more susceptible and highlights potential blood markers that could help diagnose and track the disease.
Researchers at NYU Langone Health and collaborators in the U.S. and Brazil discovered that declining blood levels of two natural molecules, acetyl-L-carnitine and free carnitine, closely correlate with the severity of Alzheimer’s, particularly in women.
These molecules are essential for brain function and energy regulation, and their depletion was observed across various stages of cognitive decline, from mild impairment to severe Alzheimer’s.
Differences Between Women and Men
The study revealed that both men and women with cognitive impairment or Alzheimer’s had lower levels of acetyl-L-carnitine in their blood.
However, only women showed significant declines in free carnitine, suggesting a potential explanation for their higher risk of developing the disease. These findings highlight a critical sex difference in how Alzheimer’s progresses, shedding light on why more women are affected.
A Link to Known Alzheimer’s Markers
Using blood samples from 93 volunteers with cognitive impairment and 32 healthy participants, the researchers found that the levels of acetyl-L-carnitine and free carnitine mirrored the amount of amyloid beta and tau proteins—well-known markers of Alzheimer’s severity.
Combining these blood markers with traditional protein measures improved diagnostic accuracy from 80% to 93%, underscoring their potential value in identifying and tracking the disease.
“Our findings offer the strongest evidence yet that declines in these molecules could act as blood biomarkers for Alzheimer’s and even for predicting early dementia,” said study lead investigator Dr. Betty Bigio.
The Promise of a Noninvasive Blood Test
Current methods for tracking Alzheimer’s involve spinal taps, which are invasive, painful, and carry risks. A blood test would offer a simpler, safer alternative for diagnosing and monitoring the disease. It could also serve as an objective tool for measuring disease progression or evaluating the effectiveness of new treatments.
Dr. Carla Nasca, senior investigator of the study, noted that the findings could lead to better therapeutic strategies. By understanding how acetyl-L-carnitine and free carnitine are produced and their role in brain health, researchers hope to identify ways to intervene before irreversible damage occurs.
Why These Molecules Matter
Acetyl-L-carnitine and free carnitine play vital roles in brain energy metabolism and cell repair. Past research by Nasca’s team has shown that acetyl-L-carnitine helps regulate genes involved in producing glutamate, a neurotransmitter essential for memory and nerve cell repair.
Damage to these processes is particularly significant in the hippocampus, the brain region responsible for memory and one of the first areas affected by Alzheimer’s.
Interestingly, acetyl-L-carnitine deficiencies have also been linked to mood disorders and depression—conditions closely tied to Alzheimer’s. This overlap raises questions about whether addressing these deficiencies could prevent depression from progressing to dementia, a topic for future research.
Next Steps
The study’s findings, published in Molecular Psychiatry, provide a solid foundation for further investigations. Researchers aim to explore the molecular pathways that control acetyl-L-carnitine production and its impact on brain chemistry.
Confirming these results in larger studies could pave the way for developing a widely available blood test for Alzheimer’s.
Such a test would not only simplify diagnosis but could also help predict the success of emerging treatments aimed at slowing or preventing the disease. With these insights, scientists are closer to understanding the complex biological processes underlying Alzheimer’s and finding ways to protect brain health.
If you care about Alzheimer’s, please read studies about the likely cause of Alzheimer’s disease , and new non-drug treatment that could help prevent Alzheimer’s.
For more information about brain health, please see recent studies about diet that may help prevent Alzheimer’s, and results showing some dementia cases could be prevented by changing these 12 things.
The research findings can be found in Molecular Psychiatry.
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