The art and science of profiling is a process of learning about someone or something based on what is already known.
For example, if you watch any of the popular crime shows on TV you’re familiar with psychological profiling, also known as criminal profiling, where a character uses behavioral and criminal clues to put together a “snapshot” of the suspect at large in order to better understand and, eventually, arrest him (or her).
Alzheimer’s disease and dementia researchers are using a type of profiling similar to this; called metabolic profiling, in order to better understand that thief of memory and independence.
So far, they’ve uncovered three distinct subtypes of Alzheimer’s disease using this process, helping to explain the variations in the way this neurological condition first shows itself and how it affects the brain.
Read on to discover these subtypes, and what they mean for the future of Alzheimer’s disease treatment.
Researchers are profiling the metabolic process in the body much like an FBI officer profiles a suspect.
The researchers analyze metabolites, small molecules created in the chemical reactions of metabolism, in body fluids such as blood, plasma and urine to get a snapshot of the health of the body.
Each cellular process in the body leaves a unique “chemical fingerprint” that can be used to identify diseases and other problems before they start showing up in full-blown symptoms, such as memory loss.
In a study performed at the University of California‒Los Angeles (UCLA) and published in the August 2015 issue of the journal Aging, researchers took the metabolic profile of 50 people and measured the baseline against their conditions two years later.
Using this information they then determined three unique subtypes of Alzheimer’s disease.(1)
Each subtype affects different parts of the brain and exhibits specific kinds of symptoms.
This discovery could lead to earlier detection and more personalized treatment options in the future.
Subtype #1: Inflammatory
Not surprisingly, one type of Alzheimer’s disease is inflammatory, characterized by markers such as increased high-sensitivity C-reactive protein (hs-CRP) and a higher ratio of globulin to albumin.
hs-CRP is an acute-phase inflammatory reactant, meaning it occurs after the body has been inflamed.
Globulin and albumin are important proteins, and elevated ratios also indicate the presence of inflammation in the body.
In a 2002 study, researcher found that people with hs-CRP levels in the highest 3 quartiles were found to have a three-fold increased risk for dementia compared to those in the lowest quartile.(2)
We’ve known for a while that inflammation is a major precursor to all kinds of diseases, including Alzheimer’s disease, and here’s physical proof of that.
And by being able to detect the effect inflammation is having early on via metabolic profiling, there’s hope in the earliest of early detections.
Subtype #2: Non-inflammatory
The second subtype is called non-inflammatory, in which the inflammation markers are unaffected but other metabolic abnormalities are present. These include
- Insulin resistance
- Vitamin D deficiency (to learn more about vitamin D and brain health see Issue #179)
- Hyper-homocysteinemia (elevated homocysteine levels, an amino acid that can damage arterial walls and cause clotting when there’s too much in the body)
- Hormonal loss associated with early oophorectomy (removal of the ovaries)
Managing the first three markers can be done through diet and exercise, as a diet high in fruits and vegetables can rid the body of homocysteine and balance insulin, and getting outside provides vitamin D.
Subtype #3: Cortical
The third subtype is rather distinct from the first two in that it affects relatively young individuals and extends beyond the typical Alzheimer’s disease initial distribution to affect the cortex (hence the name, “cortical”), the outer layer of the cerebrum that’s responsible for memory formation and storage as well as solving problems and planning.
Cortical Alzheimer’s disease is often characterized by symptoms not related to memory loss, such as severe difficulty in understanding and calculating numbers, the inability to see and understand words and losing the ability to understand or express speech.
The researchers in the Aging study noted that the cortical subtype is often misdiagnosed or labeled atypical Alzheimer’s disease (also known as hippocampal sparing AD).
This particular subtype tends to afflict ApoE4-negative people (ApoE4 is the gene mutation associated with Alzheimer’s disease) and is also associated with zinc deficiency.(1)
To learn more about the importance of zinc for brain health see Issue #143.
As researchers continue to compile a profile of Alzheimer’s disease, we begin to see why a variety of things influence its development in different ways, such as vitamin D and zinc deficiency, overall diet and exercise regimen and inflammation.
As scientists get a clearer picture of this “criminal” we get closer to arresting it, for good.
- Metabolic profiling distinguishes three subtypes of Alzheimer’s disease. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4586104/
- High-sensitivity C-reactive protein: An early marker of Alzheimer’s? http://www.jwatch.org/jn200210110000003/2002/10/11/high-sensitivity-c-reactive-protein-early-marker#sthash.iAm6PAXx.dpuf