The brain is an incredible machine, but also a black box full of mysteries. One of the most stubborn concerns Alzheimer's and the proteins that seem to dominate its development. At the top of the list is often the tau protein. We've seen it as the "bad guy," the misfolded protein that creates havoc. But science, every now and then, tells you: "look closer."
And looking more closely, in the brains of newborns, we discover that the tau protein is there, and in industrial quantities, and it is not destroying anything at all. On the contrary. It is as if we had found the antidote in the place where we thought the poison was born. A perspective to say the least… disorienting.
Tau Protein in Newborns: A Mystery in the Cradle
For years, as mentioned, we have had a “bad guy” to fight. The tau protein (or rather, its modified form, p-tau) and amyloid are the usual suspects when it comes to Alzheimer's. They accumulate, form clumps (the infamous 'tangles') and off begins the cascade that leads to dementia that devastates so many, too many lives. It is a consolidated narrative, that of the progressive damage caused by these “toxic proteins”.
But then come scientists like Rahul Sidhu, a PhD student in neuroscience at theSheffield University, and his colleagues, and in this new study show us something that doesn't add up. Take a healthy newborn. No amyloid buildup, brain in full and wonderful construction. And yet? Levels of a specific form of tau protein, the p-tau217, are very high, well beyond those we see in a patient with full-blown Alzheimer's.
You got it right? The protein we associate with neurodegenerative disaster is present in enormous quantities in the brain that is functioning best, that of a newborn baby. And it's not doing any harm. In fact, it must be doing something. Useful. This discovery, the discovery of these 'very high' levels in healthy newborns, calls into question the idea that amyloid is always the trigger that makes tau go haywire. It suggests that these proteins may act independently, at least at certain stages of life, and that other biological processes constantly regulate tau.
The Tau Protein: When the Defender Becomes the Enemy
This is not an isolated discovery, born by chance. It aligns with previous studies on animal models (like mice, poor things, always at the forefront of science) and fetal neurons. These studies had already noted that levels of tau protein tend to peak during the early stages of development and then decline dramatically. A trend that, it seems, is reflected in humans.
So, if p-tau217 is so important and, presumably, useful for normal brain development early in life, what happens later? What changes? What flips the switch that turns a potential ally into a declared enemy? This is the real enigma. Understanding this shift (from the protective to the destructive role) could open up completely new avenues. Not only to treat Alzheimer's when it occurs, but perhaps, with a bit of luck and a lot of research, to to prevent that the switch trips.
Alzheimer's research has focused for decades on the damage caused by proteins behaving badly. This study, however, turns the tables a bit. It shows that one of these “toxic proteins” could play a vital and healthy role at the beginning of our journey. How a study revealed a novel protective role. We basically only studied a machine when it was broken, without ever asking how it worked perfectly when new.
Hope in the cradle
Learning the secrets of how a newborn’s brain manages tau and keeps it under control despite elevated levels could be the key to preserving cognitive function even in old age. It’s a bit like looking for the perfect instruction manual in its original state, rather than trying to repair the torn and stained manual. Understanding whether tau is an enemy or an ally has become crucial. And perhaps, understanding p-tau217 in newborns could actually stop the disease in adults.
It would radically change our approach to what is, let’s face it, one of the most daunting medical challenges. We’ve spent years trying to clean up the mess of accumulated proteins, untangling the tangles, plugging the damage. What if the solution was to figure out how to prevent the mess from starting? What if that knowledge was already there, silent, in the first months of life? As I wrote to you in this article, sometimes the most surprising solutions are hidden in the least expected places.
Perhaps the answer to one of the worst nightmares of adulthood is not in some hyper-technological laboratory, or in miracle drugs yet to be invented, but is written from birth, in the minds of those who are just discovering the world. A lesson in humility from the cradle. Who knows if we will be able to read it, that lesson. Or if we will continue to look for the key under the wrong street lamp.
