How Eating Brains Revealed A Clue Toward Fighting Dementia
Among all the potential things you may guess could reveal resistance to dementia, cannibalism is likely not one of them. Yet by studying a Papua New Guinea tribe called Fore, scientists have hopefully revealed another clue in the development of resistance to a deadly neurological disease called kuru, a very rare form of dementia.
Throughout history humans have developed resistance to a variety of conditions through natural selection. In some ways, this is no different. But what makes this example interesting is specifically the unique aspect of the Fore culture—eating the brains of their dead. While it's not possible for scientists to confirm with certainty that this was responsible for their protective mutation, the research is compelling—shedding new light on how the body insulates itself from disease.
Kuru itself is a prion-based (nervous system) disease, a deadly class of infectious neurological illness that may lead to death, even in otherwise healthy adults. Although prion diseases have a variety of causes, kuru is typically contracted from eating human brains, which was once common amongst certain cannibalistic tribes of Papua New Guinea.
The disease is rare in the developed world and likely poses little direct threat to you. However, Creutzfeldt-Jakob Disease (CJD), another prion-based disorder, is much more common. In fact, just recently, 15 patients were exposed to contaminated surgical instruments at a hospital in the northeast.
Prion diseases are associated with the accumulation of an abnormally folded protein, which can either be sporadic, as is the case in some instances of CJD, or acquired, as in kuru. Other more recognizable examples of prion disease include Mad Cow Disease, seen in cattle, and scrapie, seen in sheep.
The term “sporadic” indicates that the patient had no previously known risk factors, and that the disease was caused by a spontaneous event. Of all the reported cases of CJD, 85-95 percent are thought to be sporadic. CJD is the most frequent of the human prion diseases, although it is still rare with approximately one case per 1,000,000 per year worldwide. The average age of onset is between 57 to 62 years of age.
Researchers have identified some of the main risk factors of CJD, including administration of cadaveric hormones, dural graft transplants, and the use of contaminated surgical instruments—the majority of which follow surgery. It is common for hospitals to borrow expensive systems and sterilize them thoroughly, but with CJD, routine sterilization isn’t enough. There are special protocols that must be employed to make the operating room safe after a CJD exposure.
So what’s the prognosis for patients who may have been unwittingly exposed to this nefarious protein? If by chance CJD was contracted, there is unfortunately no effective treatment, and the disease is considered uniformly fatal. The incubation period for CJD ranges from 5 to 30 years; however, death usually occurs between six months to one year from the onset of symptoms. On the bright side, the odds that the at risk patients contracted CJD are very low.
That brings us back to the people of Papua New Guinea, who are resistant to this class of disease. This discovery may serve as the catalyst that enables scientist to better understand the molecular causes and possible treatments of prion based diseases, such as kuru and CJD. Scientists are on the verge of demonstrating that a single change in DNA may confer complete resistance to a fatal disease.
Better yet, Parkinson’s and Alzheimer’s are thought to harbor similar mechanisms and what is learned from CJD will almost certainly help other dementia patients.
While it may be too early to call this a breakthrough, these findings have the potential to help us more effectively understand prions, vaccines, immunotherapy, and the underlying cause of a family of deadly diseases. We are closer today than we where yesterday.