Nature, the British scientific journal
founded in 1869, is not in the business of fear-mongering. But its March cover
story may have raised some eyebrows about the nature of Alzheimer’s disease. The
article, written by Allison Abbott, considers the notion that, under very
specific conditions, Alzheimer’s could be transmitted to other people.
How could this occur? A key element is human growth
hormone, which is produced naturally by the pituitary gland and governs growth.
For many decades, pituitary glands have been salvaged from cadavers for the hormone
that can be used to address growth-related problems. I first learned about HGH
in the sports pages. After decades of allegations that many baseball players
and other athletes were using steroids to gain a competitive advantage, major
league baseball belatedly cracked down on the practice. But as steroid use declined,
human growth hormone gained in popularity.
How could human growth hormone transmit Alzheimer’s?
Abbott interviewed John Collinge, who has been examining human brains for the
past quarter-century. While studying the brains of people who at some point had
been injected with growth hormone, “It turned out that some of the preparations
were contaminated with a misfolded protein—a prion—that causes a rare but deadly
condition,” Creutzfeldt-Jakob
disease. Unlike Alzheimer’s, which often takes at least a decade to do its
dirty work, Creutzfeldt-Jakob typically kills within a single year.
For Collinge, according to Abbott, “the reason that these
brains looked extraordinary was not the damage wrought from a prion disease,
such as Alzheimer’s; it was they were scarred in another way. It was very clear
that something was there beyond what you would expect,” Collinge was quoted as
saying. “The brains were spotted with the whitish plaques typical of people
with Alzheimer’s disease.”
Collinge, Abbott wrote, was disturbed by the implications:
“That the plaques might have been transmitted from one person to another. If
true, they could have far-reaching implications: the possibility that the seeds
of the amyloid-β protein involved in Alzheimer’s could be transferred during
other procedures from one person to another,” through common medical procedures
such as blood tranfusions and organ transplants.
Not surprisingly, the news caused a stir, particularly in
Britain, where the tabloid Daily Mail featured
the headline, “Can you CATCH Alzheimer’s?”
Should the U.S. public be alarmed? Abbot suggests not,
though she poses a range of questions that researchers are trying to answer. “Could
seeds of amyloid-β proteins really be transmitted and, if so, are they
harmless or do they cause disease? And could seeds of other related diseases
involving misfolded proteins be transmitted in a similar way? In the past
decade or so, evidence has been mounting for a controversial theory that rogue
proteins, known collectively as amyloids and associated with diverse
neurodegenerative diseases,” including
Alzheimer’s, “that might share some properties of prions, including their
transmissibility.”
My takeaway is this: It’s always good policy to take
precautions in a timely fashion. But, at this point, the odds of any one person
being afflicted by this disease is exceedingly small.