Studies Find Signs of Alzheimer's Decades Before Symptoms
The Lancet Neurology recently published two new studies that suggested increasing levels of a specific brain protein in the blood and spinal fluid might be the earliest signs of diseases such as Alzheimer's and Huntington's, according to the Wall Street Journal.
The brain protein is called the neurofilament light chain (Nfl) and is released following brain cell damage. Researchers believe that it could be the earliest sign for neurodegenerative diseases, including Alzheimer's, Huntington's, ALS, and Parkinson's. Scientists believe that the cell deterioration associated with these diseases occurs years or decades before symptoms begin. Once symptoms do appear, the effects are almost irreparable and have high mortality rates. The ability to find these diseases at their earliest points would give medical care professionals time to treat the disease before it accelerates.
The study on Nfl levels in cerebrospinal fluid was conducted by an international team of researchers using 64 subjects all carrying the Huntington's gene mutation. They found that they could detect Huntington's at least 24 years before symptoms began. “Other studies have found that subtle cognitive, motor and neuropsychiatric impairments can appear 10-15 years before disease onset,” said researcher, Rachael Scahill. “We suspect that initiating treatment even earlier, just before any changes begin in the brain, could be ideal, but there may be a complex trade-off between the benefits of slowing the disease at that point and any negative effects of long-term treatment.”
This research would be a breakthrough for the medical community and would allow new preventative treatments to be tested before any irreparable damage was caused by the disease. “We have found what could be the earliest Huntington’s-related changes, in a measure which could be used to monitor and gauge effectiveness of future treatments in gene carriers without symptoms,” says researcher Paul Zeun.
Another study showed that examine Nfl levels for Alzheimer's disease was more effective in the blood. "We wanted to determine the earliest age at which plasma NfL levels could distinguish individuals at high risk of Alzheimer's," said Yakeel Quiroz, from Harvard Medical School. The study was conducted with 1,000 subjects who were at high risk of developing Alzheimer's aged between 8 and 75 years old. The researchers found that increasing Nfl levels could be detected as early as age 22. The onset of symptoms for Alzheimer's usually begins around age 44, but finding the disease would give the patient a 22-year head start.
"Our findings add to the growing evidence that blood-based NfL can be useful in detecting neurodegeneration, starting with very early, subtle elevations way before the onset of clinical symptoms,” said Quiroz. “We need more studies to further explore NfL as a way to inform prognosis and evaluate treatments in Alzheimer's disease.”
Neither test is clinically available right now. Additional testing and work must be conducted to determine if Nfl is effective in determine the earliest stages of neurodegenerative diseases.