Piecing Together the Alzheimer's Puzzle

Alzheimer’s is a disease that affects 290,000 Canadians - which is one in 20 over the age of 65 with the numbers increasing to one in four for those over 85.  But those that are younger are also at risk.  Alzheimer Society of Canada (ASC) recently stated 71,000 Canadians under the age of 65 are living with Alzheimer’s or a related dementia, of which approximately 70 percent or 50,000 are 59 or younger.  

Canadian women are particularly vulnerable and make up close to 75 percent of all diagnosed with Alzheimer’s.  The ASC believes that within 25 years, Canadians with the disease or a related dementia will more than double, bringing the total up to between 1 and 1.3 million people.We will see these numbers increase as our population ages.  

By 2050, the number of cases around the world will quadruple to around 106 million people, according to researchers at the Johns Hopkins Bloomberg School of Public Health in Baltimore.   The Asian continent is predicted to have the biggest jump from 12.6 million people currently with Alzheimer’s (half of all the cases in the world) to a staggering 62.8 million by 2050.

Alzheimer’s slowly affects how people understand, think, remember and communicate with symptoms that include memory impairment, behavioural changes and dementia.  The Alzheimer Society of Canada lists 10 warning signs on their website (http://www.alzheimer.ca/english/disease/warningsigns.htm) that outline what to look for if you suspect someone of having the disease.  

At this time, there is no cure for the Alzheimer’s; however, researchers are encouraged by the progress that has been made in understanding how the disease begins by attacking the brain years before the symptoms appear.  This will help to isolate what causes the condition and who is susceptible - key pieces to the puzzle.

According to the journal Nature Genetics, a group of Canadian researchers were able to isolate a gene that may increase the risk of Alzheimer’s.  The January 2007 report suggested that people with the disease seem to have lower levels of SORL1 in their blood cells.  When the activity of SORL1 was suppressed, cells made more of amyloid beta peptide - a substance that is suspected to play a key role in causing Alzheimer’s.

SORL1 controls the distribution of amyloid precursor protein (APP) inside nerve cells of the brain.  When SORL1 works normally it prevents APP from being degraded into A-beta as it stimulates the formation of plaques.  Then as the amyloid gathers, brain cells begin to die, resulting in disorientation and progressive memory loss.

At the current time, the only way to diagnose Alzheimer’s is through an autopsy.  But new findings in December 2006 seems to indicate that a test can help in determining if a person may develop the disease later in life.

Researchers at New York’s Weill Cornell Medical College used proteomics to examine 2,000 proteins found in the spinal fluid of 34 people who died with autopsy-proven Alzheimer’s and compared it with the spinal fluid of 34 non-demented people.  They discovered a difference of 23 proteins which together formed a fingerprint of the disease.

They continued looking for the same protein pattern in 28 other people - some had symptoms of Alzheimer’s or other dementia while others were healthy. The test identified nine out of 10 patients that doctors had suspected with Alzheimers.

In their quest for a cure, scientists from the University of Rochester Medical Center in Rochester, N.Y., found a way to halt the symptoms of Alzheimer’s.  Their study identified a protein that could be used as a “sponge” to absorb the toxic plaque (or amyloid beta) that builds in Alzheimer’s patients.  It can neutralize up to 90 per cent of the plaque and helped improve brain function.  

The protein is called soluble low-density lipoprotein receptor-related protein (or soluble LRP) and research is underway to create a form that can be tested on people.

Researchers in California recently concluded that Alzheimer’s is a disease of aging since the piece of the brain that clears away the toxic buildup of free radicals becomes less efficient and therefore, increases the susceptibility to the disease.  Our bodies use anti-oxidants in foods to neutralize the damage.

Dr. Qi Dai of Vanderbilt University Medical Center in Nashville, Tenn. said, “Fruit and vegetable juices may play an important role in delaying the onset of Alzheimer’s disease.”  By drinking three or more servings of juice per week compared to those who drank it less than once per week, researchers found the risk of developing signs of Alzheimer’s was lowered by 76 per cent.

Studies suggest it’s actually the protective polyphenols in the juice rather than the vitamins that show a strong neuroprotective effect.  It is specifically the juice that is pressed from whole, fresh fruits and vegetables since the polyphenols are found in the skin or rind.  Although encouraging, researchers caution that people should not jump the gun about the potential protective value of the juice since they are still unclear about what type of juice might help and how long it must be consumed.

The protective effect won’t necessarily stop Alzheimer’s but it reduces the chances after controlling other factors such as smoking, education, physical activity and fat intake which could also play a role.  The benefit was enhanced in people who carried a genetic marker called apolipoprotein E that is linked to late-onset Alzheimer’s, as well as those who were not physically active.

Canadian researchers are keen at looking at non-dietary strategies for curbing the nerve damage of Alzheimer’s.  

Studies have found that being bilingual all your life plays a factor in reducing your chances of developing Alzheimers.  The memory clinic at Baycrest Hospital in Toronto studied Alzheimer’s patients (two-thirds) and those that had other kinds of dementia.  Half had spoken at least two languages every day for 50 years or more.

Results indicated that people who only spoke one language had dementia symptoms show up at the age of 71 while bilingual people manifested the symptoms on average at the age of 75.  However, there is little change in the age of onset of symptoms for people who picked up the second language later in life.  

Alzheimer’s is a disease that has many unknown pieces to the puzzle.  With each research study we begin to piece together the facts to complete the full picture - one that becomes more vital each day as the number of Alzheimer’s patients increase as our population ages.  

SOURCE: "Understanding Alzheimer's" CBC News. 6 July 2009.