From: hounddog23x@gmail.com   
      
   What can beagles teach us about Alzheimer's disease?   
      
   AUTHOR   
      
    Elizabeth Head   
   Associate Professor at University of Kentucky   
   DISCLOSURE STATEMENT   
      
   Elizabeth Head receives funding from the National Institutes on Aging.   
      
      
   Keep your brain active. Dog via Soloviova Liudmyla/Shutterstock   
   Every 67 seconds someone in the United States is diagnosed with Alzheimer's   
   disease and new estimates suggest that it may be the third leading cause of   
   death of older people.   
      
   Alzheimer's disease is associated with losses in memory in older people that   
   become severe enough over time to interfere with normal daily functions. Other   
   signs of Alzheimer's include changes in the ability to communicate, losses in   
   language, decreased    
   ability to focus and to pay attention, impairments in judgment and other   
   behavioral changes.   
      
   People with Alzheimer's disease experience changes in their brains (which we   
   can see in autopsies). Over the course of the disease, clumps of protein   
   (called senile plaques) and tangles in neurons (called neurofibrillary   
   tangles) accumulate. These    
   plaques and tangles interfere with how the brain works and disrupt connections   
   that are important for intact learning and memory ability.   
      
   The majority of studies to develop treatments for Alzheimer's disease use mice   
   that are genetically modified to produce human proteins with mutations. But   
   these mutations are usually present in less than 5% of people with Alzheimer's   
   disease. This    
   limitation can make it difficult to translate benefits of a treatment tested   
   in mouse studies to people. However, there are several animals that naturally   
   develop human-like brain changes that look much like Alzheimer's disease,   
   including dogs.   
      
   Old dogs, new research tricks   
      
   Old dogs may teach us a great deal about aging. As dogs get older, some   
   develop learning and memory problems, much like we do. And like people, not   
   all old dogs become impaired. Indeed, some old dogs remain bright and able to   
   learn just as well as    
   younger dogs, although they may be a little slower in reaching high levels of   
   performance.   
      
   When an older dog has cognitive problems, we may see them as changes in   
   behavior that can be disruptive to the relationship between owners and pets.   
   For example, an old dog with cognitive problems may forget to signal to go   
   outside, may be up at night    
   and sleep all day, or have trouble recognizing people or other pets in the   
   family. This is similar to a person with Alzheimer's disease who may have   
   difficulty communicating, disrupted sleep/wake cycles and trouble remembering   
   family and friends.   
      
      
   Staying sharp.  Soloviova Liudmyla/Shutterstock   
   When aged dogs show cognitive changes not caused by other systemic illnesses,   
   they are related to brain changes that are strikingly similar to people. For   
   example, old dogs develop senile plaques in their brains that are made of a   
   protein that is    
   identical to one that humans produce. This protein, called beta-amyloid, is   
   toxic to cells in the brain.   
      
   Unlike mice and rats, old dogs naturally develop significant brain pathology   
   like we see in people. In this way, aging dogs may resemble aging humans in a   
   more natural or realistic way than mice with genetic mutations.   
      
   There are many other changes in the brains of people with Alzheimer's disease   
   that are similar in aging dogs. These include changes in the blood vessels of   
   the brain, the accumulation of damaged proteins and losses in cells, and   
   chemicals that support    
   cells in the brain. These changes may be modified by lifestyle factors.   
      
   Healthy living, healthy aging   
      
   There are many reports of how our lifestyle can be good or bad for aging. The   
   food we eat can be a potent contributor to how our brains age. For example,   
   several studies in people show that antioxidant-enriched diets (including lots   
   of fruits and    
   vegetables) and the Mediterranean diet are associated with healthier brain   
   aging.   
      
   Physical exercise and good cardiovascular health also appear to be associated   
   with a lower risk of developing Alzheimer's disease and cerebrovascular   
   disease, which is a cause of dementia. Keeping your brain active and   
   challenged with puzzles, brain    
   games and an engaging social life, are all linked to better memory and less   
   risk of disease and studies are ongoing in people to measure the effects   
   systematically.   
      
      
   Eat well.  Nicki Mannix, CC BY   
   Beagles and the brain   
      
   Dogs may be very well suited to help us understand how these lifestyle factors   
   help our brains as we get older. Our lab initially began studying beagles in   
   the early 1990s as there was interest in developing a drug to treat "dog   
   dementia" based on pet    
   owners observations of changes in behavior in their older dogs. At that time,   
   little was known about learning and memory changes in aging dogs (beagles over   
   eight years of age) and our earliest research was designed to find ways to   
   systematically measure    
   these changes.   
      
   The first step in doing this was to teach dogs to look at different objects   
   (for example a Lego block or a toy truck) and learn that one of the two always   
   hid a food reward. When we switched the food reward to the object that was   
   previously not rewarded,    
   older dogs kept choosing the wrong object. Young dogs very quickly switched   
   over to the new object.   
      
   When we counted the number of errors dogs make to learn the problem, old dogs   
   made many more errors overall. Interestingly, not all old dogs were impaired.   
   Another subset of old dogs showed significant losses in their ability to   
   remember information and    
   some showed changes in their ability to be "flexible" in changing behaviors.   
      
   This is very similar to people. Not everyone ages in the same way - some   
   people remain sharp as tacks well into their older years. After measuring   
   learning and memory changes in dogs, we next studied the brain changes that   
   were most strongly linked to    
   these cognitive losses. We found that senile plaques in the brains of old dogs   
   were more frequent in the animals that had learning and memory problems. In   
   our more recent studies, we have been seeking ways to improve brain health in   
   old dogs with the    
   hope that these approaches can translate to healthy aging in people.   
      
      
   Keep running.  Marco Bellucci, CC BY   
   For instance, in several studies of aging in beagles, we have found that a   
   diet rich in antioxidants that includes vitamins E and C, and importantly,   
   fruits and vegetables, can lead to wonderful benefits in learning and memory   
   ability that can be    
   maintained for years.   
      
      
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