A groundbreaking scientific advancement is offering fresh insights into Alzheimer’s disease, with researchers identifying a specific type of brain cell that appears to play a critical role in the disease’s development. The discovery, stemming from a study conducted by researchers at the French National Institute of Health and Medical Research (Inserm), University of Lille, and Lille University Hospital, centers on the function of specialized cells and their connection to the buildup of tau protein – a key biological marker associated with Alzheimer’s. This research offers a potential new avenue for understanding and ultimately treating this devastating neurodegenerative condition.
Alzheimer’s disease is a leading cause of dementia worldwide, characterized by a progressive decline in memory and cognitive abilities, impacting decision-making, reasoning, and spatial orientation. The disease’s progression involves the gradual deterioration of neurons, beginning in the hippocampus – the brain region crucial for memory – and spreading to other areas. A hallmark of Alzheimer’s is the abnormal accumulation of tau protein within neurons, disrupting their normal function. Understanding how and why this accumulation occurs is central to developing effective therapies.
In a healthy brain, neurons produce limited amounts of tau protein, which is then released into the cerebrospinal fluid – the fluid surrounding the brain and spinal cord – and eventually cleared through the bloodstream. But, in individuals with Alzheimer’s, the structure of tau protein changes, preventing it from fulfilling its normal role and leading to its pathological buildup within neurons, ultimately causing neuronal dysfunction and cognitive decline. Researchers are now focusing on the mechanisms that govern this process, and the role specific brain cells play in it.
The new study focuses on a type of brain cell called “tanycytes,” located near the brain’s ventricles. These cells are known to regulate the exchange between the blood and cerebrospinal fluid. For over two decades, the research team, led by Vincent Prévot, has studied tanycytes, recognizing their role in transporting hormones like leptin, which regulates appetite and energy balance. Now, they’ve discovered that these cells also directly transport tau protein from the brain to the blood, a finding published in the journal Cell Press Blue [1].
To reach this conclusion, researchers injected tau protein into the cerebrospinal fluid of animal models and tracked its movement using fluorescent imaging techniques. The results showed that tanycytes capture tau protein from the cerebrospinal fluid and transport it along their extensions to capillaries, where it’s released into the bloodstream. This led researchers to hypothesize that tanycytes form a primary pathway for removing tau protein from the brain.
To test this hypothesis, the team genetically modified tanycytes to produce botulinum toxin, effectively disabling their function. This disruption halted the transport of tau protein from the cerebrospinal fluid to the blood, resulting in its accumulation within the brain. Notably, mice with disabled tanycytes exhibited early signs of dementia compared to control groups. These findings strongly suggest that functional tanycytes are essential for maintaining healthy tau protein levels.
Further validating these findings, the researchers examined brain tissue from individuals who had died from Alzheimer’s disease. Analysis revealed the presence of tau protein within tanycytes, and significant damage to these cells. Their cellular extensions were fragmented and broken, disrupting the normal pathway for protein transport. Importantly, this damage was not observed in the brains of individuals with other forms of dementia, suggesting it may be specific to Alzheimer’s disease [1].
This discovery opens new avenues for developing Alzheimer’s treatments. If maintaining the health of tanycytes proves crucial in preventing tau protein accumulation, these cells could become a new therapeutic target. Researchers are now investigating ways to protect and restore tanycyte function in individuals at risk of or already diagnosed with Alzheimer’s disease.
The research builds on existing knowledge of Alzheimer’s disease, which currently affects an estimated 900,000 people in France, with 225,000 new cases diagnosed each year [3]. Globally, over 35 million people are living with the condition. Even as the disease is rare before age 65, its incidence increases significantly with age, affecting over 15% of individuals over 80 [3].
Looking ahead, further research will focus on understanding the specific mechanisms that cause tanycyte dysfunction in Alzheimer’s disease and exploring potential therapeutic interventions. A six-year risk assessment study published in April 2025 also highlights the potential of plasma-based biomarkers for early detection of Alzheimer’s risk [4]. These advancements, combined with a deeper understanding of cellular processes like those involving tanycytes, offer hope for more effective diagnosis and treatment strategies in the future.
This research represents a significant step forward in unraveling the complexities of Alzheimer’s disease. Continued investigation into the role of tanycytes and other cellular mechanisms will be crucial in the ongoing effort to combat this devastating illness.
Disclaimer: The information provided in this article is for general knowledge and informational purposes only, and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
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