A study from the University of São Paulo (USP) suggests that people with Down syndrome are more prone to develop Alzheimer's disease due to early-onset neuroinflammation. The study, published in the respected journal Alzheimer's & Dementia and backed by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), points to new possibilities for researching and preventing Alzheimer's drugs, which could help slow down or stop the disease many years before symptoms show up. 

Down syndrome, a genetic disorder produced by an extra copy of chromosome 21, has long been associated with rapid ageing. According to studies, up to 90% of people with Down syndrome get Alzheimer's before the age of 70, with symptoms commonly appearing in their forties. Scientists have known for a long time that the amyloid precursor protein (APP) gene on chromosome 21 leads to too much beta-amyloid, a sticky substance that builds up between nerve cells and disrupts communication. 

However, new USP research indicates a previously overlooked player: neuroinflammation, which begins unexpectedly early. Using advanced positron emission tomography (PET) imaging, researchers discovered elevated inflammatory activity in the brains of young adults with Down syndrome, some as young as 20 years old. This inflammation showed in crucial brain regions such as the frontal, temporal, and limbic lobes, which control memory and emotion. 

The study included 29 people with Down syndrome and 35 without the disease, ranging in age from 20 to 50. PET scans showed that neuroinflammation happened before a lot of beta-amyloid plaque built up, suggesting that inflammation might start the chain of events that leads to Alzheimer's disease. 

"We found a clear relationship: the more neuroinflammation, the more beta-amyloid accumulation," explained Daniele de Paula Faria, lead researcher of USP's Nuclear Medicine Laboratory. "This process may be a key therapeutic target for Alzheimer's prevention." 

Complementary investigations in genetically engineered mice confirmed the human findings, demonstrating that inflammatory responses preceded amyloid accumulation. This dual-model approach reinforces the case for early intervention as a potential target for Alzheimer's medication development. 

The researchers discovered that microglia, the brain's immune cells, initially behave defensively but then become destructive. This biphasic inflammatory pattern shows that, while the brain attempts to repair itself initially, chronic inflammation eventually destroys neurones. "It's as if the brain's protection mechanism eventually backfires," Faria told me. 

This finding changes the way scientists think about Alzheimer's disease progression. Instead of focusing solely on plaque removal, new research lines could prioritise reducing neuroinflammation long before plaques emerge. Early-stage therapy could help to delay or prevent the disease, especially in genetically sensitive populations, such as people with Down syndrome. 

This study redefines Alzheimer's as a syndrome that begins years before memory loss by finding neuroinflammation as a biomarker that occurs before beta-amyloid deposits form. It also allows for real-time inflammation monitoring, which aids researchers in testing the efficacy of new anti-inflammatory medicines on living patients. 

This potential may allow persons with Down syndrome, who are frequently excluded from typical Alzheimer's trials, to finally engage in research that is tailored to their specific disease profile. "Detecting inflammation in living brains allows us to track treatment progress and personalise care," according to Faria. 

Despite the elusive nature of a cure, this discovery marks a significant milestone in the development of Alzheimer's medications. Scientists hope that by addressing inflammation rather than waiting for permanent brain damage, they can alter the course of one of the world's most severe neurodegenerative illnesses.