Leading To Dementia

"If that [transmission] is shown in just one case ... public-health thinking would need to rise to meet that challenge."
"It's very important to get ahead as far as you can of something that may be an issue in even a few cases. You're always looking for things that might be coming. Precaution has become part of the basic name of the game in public health."
Dr. Michael Coulthart, scientist, Public Health Agency of Canada

David Paul Morris/The Brain Observatory    Researchers will examine preserved brains, like the one in this file photo, from Canadians diagnosed with an ailment similar to mad cow disease in a quest for the cause of Alzheimer's disease

Decades ago when horrible news items were front and centre in the media coming out of Great Britain over Creutzfeldt-Jakob disease (CJD), transmitted from affected animals (mad-cow disease) to people unknowingly consuming other animals which had been fed the entrails of sick cows, the world was transfixed with fear and revulsion.

I had a friend in Atlanta, Georgia where I lived at the time, who had undergone breast removal surgery for cancer, and she was recovering from that ordeal well enough, a single mother of a teen-age girl. Then she became mysteriously ill, felt weak and, not in control of her movements, very shaky and insecure, but she kept coming to work because she had to live. She would ask me to accompany her, so she could lean on me when she took public transit when I was doing the same.

None of us thought much of it, because we almost thought she was simply being theatrical, perhaps suffering a bit of self-doubt about herself after undergoing her mastectomy and that this would pass. And then, after awhile, she really was unable to function, and shortly afterward went into a coma, was hospitalized and lay for months, comatose, unaware of anything, until she finally died. Word came to us that she had died of something we'd never before heard of: Creutzfeldt-Jakob.

The surgical instruments used in her medical procedure had been infected, and not adequately sterilized, and the result was that this woman died a puzzling, dreadful lingering death. People began avoiding eating beef in the full-scale public fear of contracting this dreadful disease, and it is a dreadful disease. But then, so is a more common one that we're more familiar with, that afflicts  hundreds of thousands of people, though its cause seems more 'natural', in that is is linked to ageing.

Alzheimer's, or frontal lobe dementia, or any other type of dementia that haunts society has more victims than we can imagine, and represents the dread of the elderly, although it can affect people in  younger age groups in their mature years as well. We're told by researchers to keep our brains actively challenged, to exercise our bodies, the two cautions that are likeliest to help in ensuring our brains remain intact.

But now another complication has surfaced, the realization that people who have had certain transplants to address a medical condition may have received more than medical science realized at the time. That, for example, the use of cadaver transplants of brain material may lead to the transmission of Alzheimer's disease.

Evidently, the proteins called prions, described as "misfolded" which infected surgical instruments despite best-practise sterilization methods, set a similar pattern for the transmission of Alzheimer's. The three scientists who have alerted the medical community to this emerging problem caution that the evidence of transmissibility is not yet definitive, and that where they suspect this has occurred has been on rare occasions.

The number of Canadians living with Alzheimer's -- until they no longer do -- is expected to double in fifteen years' time from the current 750,000. Canada's is a rapidly ageing population. But the possibility rears it ugly head that, just like mad-cow (CJD) disease that can be transmitted by eating infected meat, by treatment with contaminated brain tissue or through blood transfusions, so too can Alzheimer's.

In Britain it was discovered five months ago that eight fairly young patients had contracted and died from CJD after receiving growth hormone from the pituitary glands of dead people. It was discovered by researchers that half of those afflicted had Alzheimer's-related amyloid plaque in their brains and blood vessels. And a month ago Swiss researchers found similar situations arising from seven people whose grafts from cadavers of the membrane that covers the brain and spinal cord had resulted in CJD.

Dr. Coulthart, who is director of CJD surveillance for the Public Health Agency and his colleagues believe that four Canadians acquired Creutzfeldt-Jakob from grafts they had received of that same dura mater (brain membrane) which led to their deaths from 1998 to 2003. There is skepticism among experts that Alzheimer's could be transmissible. Some of them point out that other elements must be taken into account; cardio-vascular health, ageing, environment and genetics.

"It's really complex, this business of trying to find the causal change that leads to dementia", noted Dr. Larry Chambers, a University of Ottawa professor, and scientific adviser to the Alzheimer's Society of Canada. Who repeats the advice of due diligence to one's ongoing health; that evidence exists that consuming a heart-healthy diet and regular exercise still is recognized as the most effective way to lower dementia risk, as well as risk of acquiring other chronic diseases.

"I wouldn't become anxious about it", advised Dr. Paul Verhoeff, a psychiatrist and dementia expert at Toronto's Baycrest Health Sciences. Two things at least has been removed from the list of potential transmission in that growth hormone now is produced synthetically, and dura mater grafts are no longer part of the medical protocol.

Between 1958 and 1985, a number of individuals with short stature received shots of human growth hormone extracted from the pituitary glands of cadavers. The gland is a pea-sized structure that sits at the base of the brain. Some of these samples were contaminated with prions that caused certain patients to develop Creutzfeldt-Jakob disease (CJD), a rare and fatal brain disorder. Treatments ceased once these reports came to light, but by that time an estimated 30,000 people had already received the injections. As of 2012, researchers have identified 450 cases of CJD worldwide that are the result of these growth hormone injections and other medical procedures, including neurosurgery and transplants.
Misfolding of the amyloid-beta proteins is a hallmark of Alzheimer’s. Previous studies have shown that minute amounts of amyloid-beta injected into animals such as mice or monkeys act as seeds that initiate a chain reaction of protein misfolding that resembles the pathology of Alzheimer’s. However, until now, no studies have found evidence that this process occurs in humans.
Scientific American