By: Dr. Karin Schon, CCAD 2013 Participant, as taken from her blog ‘Exercise and the Brain’ (http://exerciseandthebrain.wordpress.com/). View original post.
Scenes from the inspirational documentary “Herbstgold” (Autumn Gold) about five senior athletes aged between 80 and 100 years
According to a 2013 report by the Alzheimer’s Association in 2011 new criteria and guidelines for the diagnosis of Alzheimer’s disease were proposed. These changes were suggested, because new research has led to new potential biomarkers. These biomarkers may soon reliably detect brain changes associated with Alzheimer’s disease, especially amyloid beta plaques and neurofibrillary tangles (see my previous post), before symptoms, such as memory problems, are even noticeable. The proposed changes are about two things: 1) three new stages of Alzheimer’s disease and 2) new biomarker tests.
Three proposed stages of Alzheimer’s disease
The first stage, a preclinical or pre-symptomatic stage, is a stage at which pathology in the brain can already be detected before any symptoms (memory loss, language difficulties, etc.) are evident. Think about it this way: supposedly, you’re at risk of developing heart disease, because you have high blood pressure, are obese, have diabetes. What does your doctor recommend? Your doctor suggests treating these symptoms so that you will hopefully never be diagnosed with heart disease in the future. Wouldn’t it be great if it were the same way with Alzheimer’s disease? If we were able to detect those plaques and tangles in thepreclinical stage? If there were a treatment available to reduce, let’s say, the amount of amyloid beta in your brain, wouldn’t this perhaps mean that someday in the future it may be possible to prevent Alzheimer’s disease? Unfortunately, we’re not there yet, but these are exciting times! The second proposed stage is one where mild cognitive changes are apparent – the affected individual would complain about memory changes, and an increase in memory lapses is noticeable to loved ones. But these changes are not so severe yet that activities of daily living (anything from balancing the checkbook to bathing) become very difficult or impossible to do. The third and final stage in then the Alzheimer’s disease stage. Together, these three stages cover the whole continuum of the development of Alzheimer’s disease.
Because we cannot easily check if there are amyloid beta plaques or signs of injured brain cells in the living human brain, biomarkers are currently being developed to see if it is possible to detect these in other, less invasive, ways, for example in a blood sample or in cebrebro-spinal fluid, the fluid that surrounds your brain and spinal cord. The exciting thing is that new neuroimaging tools have been developed that allow one to look for markers of amyloid beta in the living human. One of these techniques, called “Pittsburgh Compound B Imaging” or short “PiBImaging” can visualize a patient’s amyloid burden. The picture shows low levels of amyloid in the healthy brain (Control) shown in cold colors, but large amounts of amyloid in the brain of a patient withAlzheimer’s disease (AD) shown in red and yellow.
So what is the billion dollar question?
The 2013 report from the Alzheimer’s Association (download report here) states that currently an estimated 5.2 million Americans have Alzheimer’s Disease. This number is expected to rise to a whopping 13.8 million by 2050. In terms of economic costs this translates to:
- 17.5 billion hours of unpaid care primarily by immediate family members thought to be valued at 216 billion dollars
- 9.1 billion dollars in health care costs in the U.S. for caregivers because of the high physical and emotional impact of caring for someone with Alzheimer’s disease
- Caregivers‘ lost hours of work due to care-giving
- 203 billion dollars of payments for health care, long-term care and hospice per year
The billion dollar question of Alzheimer’s disease research is about finding so-called disease-modifying therapies. Targeted at the preclinical stage of Alzheimer’s disease these therapies should be able to prevent and/or reduce the accumulation of amyloid beta plaques and neurofibrillary tangles in the brain long before Alzheimer’s disease is diagnosed. Even if we cannot cure Alzheimer’s disease, if we can at least slow down progression, the huge economic burden placed on society and the physical and emotional burden placed on caregivers could potentially be dramatically reduced.
Why write this story for a blog on exercise and the brain?
In a previous post I already discussed exercise as a potential strategy to reduce the risk of developing Alzheimer’s disease (link). Here, I’m going one step further: could aerobic exercise, when targeted at the preclinical stage, e.g. during midlife, potentially reduce the brain pathology associated with Alzheimer’s disease? While studies on this topic are currently in the planning stage or ongoing , we’re a long way from knowing the answer. Research using animal models of Alzheimer’s disease is promising, however. Most likely, studies will use PiB Imaging in combination with putative biomarkers, structural brain imaging and cognitive testing to figure out the role of exercise as a potential disease-modifying treatment. These are exciting times for Alzheimer’s research and its translation to clinical care. For now though, let’s stay positive, and, most of all, healthy! It’s never too late to start exercising and eat healthy!