Credit: Acris antibodies, Autotaxin protein at cytoplasm
An enzyme found in the fluid around the brain and the spine is giving researchers a snapshot of what happens inside the minds of Alzheimer’s patients how that relates to cognitive decline. The researchers say higher levels of the enzyme, autotaxin, significantly predict memory impairment and Type 2 diabetes. Just a one-point difference in autotaxin levels - for example, going from a level of two to a three - is equal to a 3.5 to 5 times increase in the odds of being diagnosed with some form of memory loss.
Autotaxin, often studied in cancer research, is an even stronger indicator of Type 2 diabetes. A single point increase reflects a 300 percent greater likelihood of having the disease or pre-diabetes. The discovery is found to be important because of autotaxin’s proximity to the brain. This specific group of scientists have been looking for metabolic markers which are closer to the brain. They also seek markers that reliably scale up with the disease and have consistently higher levels across the Alzheimer's spectrum which is as directly inside of the brain as we can get without pinching is tissue biopsy.
In a previous research, it was found that a strong association between insulin resistance and memory decline and detrimental brain outcomes, increasing the risk for Alzheimer's disease (AD).
Insulin resistance is a good indicator but it has limitations which do not consistently translate any change in the body to the brain. Therefore, the correlation with this new enzyme found in the cerebrospinal fluid is so important with regards to this study. “It has a higher predictive rate for having AD” said a research involved in the study. “We also found correlations with worse memory function, brain volume loss and the brain using less blood sugar, which have also been shown with insulin resistance, but autotaxin has a higher predictive value.”
The fact that autotaxin is a strong predictor of Type 2 diabetes and memory decline emphasizes the importance of good physical health. Researchers say people with higher levels of autotaxin are more likely to be obese, which often causes an increase in insulin resistance.
autotaxin levels can determine the amount of energy the brain is using in areas affected by AD. People with higher autotaxin levels had fewer and smaller brain cells in the frontal and temporal lobes, areas of the brain associated with memory and executive function. As a result, they had lower scores for memory and tests related to reasoning and multitasking.
Autotaxin is related to less real estate in the brain, and smaller brain regions in AD mean they are less able to carry out their functions, said a researcher. Similar applies to blood sugar. If the brain is using less blood sugar, neurons have less fuel and start making mistakes and in general do not process information as quickly.
Researchers analyzed data from 287 adults collected through the Alzheimer's Disease Neuroimaging Initiative, a public-private partnership working to determine whether MRI and PET scans as well as biological markers can measure the progression of cognitive impairment and AD. The data came from adults ranging in age from 56 to 89 years old. Study participants completed various tests to measure cognitive function. This included repeating a list of words over various time increments.