23/06/2026
This is important:
The beta-amyloid plaque hypothesis:
The Lesné Scandal
The amyloid hypothesis — that amyloid-beta plaque accumulation is the primary driver of Alzheimer’s — was first championed in 1992. By the early 2000s it was facing growing scepticism, as multiple experimental drugs targeting plaques had failed to slow cognitive decline.
Then in 2006, Sylvain Lesné published what appeared to be a landmark paper in Nature claiming to show the first tangible evidence of a cause-effect relationship between amyloid plaques and memory impairment.  His team claimed to have identified Aβ*56, a specific amyloid-beta protein assembly, as the agent responsible for memory loss in aging mice, even in the absence of the neuron death typically associated with Alzheimer’s. The paper was hailed as landmark science and cited hundreds of times. 
Failures to replicate the results were ignored, and Lesné was continuously awarded coveted multi-million dollar NIH grants. Annual NIH support for studies with the keywords “amyloid, oligomer, and Alzheimer’s” skyrocketed to nearly $300 million in 2021. 
In 2022, neuroscientist Matthew Schrag raised the alarm. Investigators discovered that Lesné had systematically manipulated images, duplicated data, and fabricated results across multiple publications spanning over 15 years.  Specifically, image forensics experts found evidence of selective editing in Western blot images — the visual readouts used to show protein presence and quantity. 
The 2006 Nature paper was ultimately retracted in 2024. According to Retraction Watch, it is the second most highly cited paper ever retracted.  In December 2025, a further related paper in Science Signaling was also retracted after a University of Minnesota investigation found the concerns about manipulated images were valid.  Lesné has since resigned.
Was It Wider Than One Paper?
Yes. Investigative journalist Charles Piller — who broke the original story — subsequently published a book titled Doctored: Fraud, Arrogance, and Tragedy in the Quest to Cure Alzheimer’s, revealing systemic issues that have plagued the field for decades. Beyond Lesné, he uncovered manipulated data from Cassava Biosciences and other researchers, with figures at institutions including the NIH implicated — their manipulated data having “supported” various patent filings and clinical trials. 
Does This Invalidate the Amyloid Hypothesis Entirely?
This is where it gets nuanced. Most scientists argue: not entirely. Some researchers at the time noted that the Lesné/Ashe paper had far less effect on the direction of the field than the Science exposé implied, and that the amyloid-beta oligomer work was just one paper among many others claiming that Aβ oligomers are the key toxic species in AD pathogenesis — meaning the field would not necessarily have developed differently without it. 
The broader amyloid hypothesis still has independent support from genetics (mutations in APP and related genes reliably cause early-onset Alzheimer’s), from autopsy data, and from the modest but real clinical effects of the recently approved drugs lecanemab and donanemab. However, the scandal has justifiably intensified debate about whether the field over-invested in a single hypothesis for too long, and at enormous cost to patients and public funds.
In short: the fraud was real, significant, and had cascading consequences for research funding and drug development. But it targeted a specific sub-hypothesis (Aβ*56 oligomers) rather than the entire amyloid framework — which remains contested but not wholly discredited.
