The irregular buildup of tau protein in the brain can form “tangles,” which researchers link to several brain disorders, including Alzheimer’s disease. This may have implications for detecting and treating Alzheimer’s.

Each year, millions of people worldwide receive a diagnosis of Alzheimer’s disease. Although this condition has no cure, researchers are making important strides in understanding how it develops.

Scientists who study the brains of people with Alzheimer’s document the location and amount of abnormal tau protein clusters. This article explores what we currently know about tau and its role in Alzheimer’s disease.

Tau proteins are a structural component of all cells, including nervous system cells called neurons. Tau proteins bind to long, hollow fibers called microtubules to stabilize them.

Microtubules are crisscrossed in a lattice-like structure within the outer part of a neuron. They allow the neuron to maintain its shape. They also help with nutrient transport and cell division.

Scientists have linked Alzheimer’s disease to tau protein irregularities in the brain. These irregularities cause tau to detach from microtubules, which then become weak and collapse.

This abnormal tau clumps together to form dense clumps of fibers known as neurofibrillary tangles. Neurofibrillary tangles block a neuron’s ability to communicate with other neurons.

According to a 2022 literature review, research shows that the presence of tau neurofibrillary tangles is positively correlated to signs of Alzheimer’s. In other words, more tau tangles usually mean more symptoms.

But Alzheimer’s disease is complex, and abnormal tau isn’t the only observable brain change. Deposits of beta-amyloid protein, known as plaques, are another hallmark.

Researchers are currently investigating how these two proteins interact to lead to the development of Alzheimer’s. One emerging theory suggests that beta-amyloid plaques trigger tau tangles to spread throughout the brain.

Is tau protein linked to other types of dementia?

Research has linked tau protein to several other illnesses that cause dementia. Tauopathies are a category of neurodegenerative disorders associated with abnormal tau.

Some known tauopathies include:

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Experts believe certain molecular changes play a role in Alzheimer’s-related tau buildup.

One such process is called phosphorylation. During tau phosphorylation, enzymes help phosphate molecules bind to tau.

Studies show a link between increased tau phosphorylation (hyperphosphorylation) and tau tangles in the brains of people with Alzheimer’s. However, tau hyperphosphorylation doesn’t always cause tau buildup.

In addition, it’s not entirely clear what triggers tau hyperphosphorylation. One hypothesis suggests that chronic inflammation plays a role.

Doctors use two tests to measure tau buildup in the brain.

PET scans are a type of brain imaging technique. Known as a tau-PET, this imaging test uses a special dye to help doctors visualize tau tangles in the brain.

Doctors can also measure tau protein levels by testing the cerebrospinal fluid surrounding the brain. They can extract this fluid via a lumbar puncture, also known as a spinal tap.

Researchers are also exploring the possibility of using a blood-based marker of tau buildup called p-tau. In other words, detecting tau may soon be possible using a simple blood test.

Alzheimer’s treatments that stop tau hyperphosphorylation and the formation of tangles are currently in development. Some are even undergoing clinical trials.

One therapy is a vaccine designed to train your immune system to destroy abnormal tau before it affects neurons. AADvac1 has the potential to slow the progression of Alzheimer’s disease. It’s currently undergoing clinical trials.

Other potential therapies include protein kinase inhibitors (PKIs) and protein phosphatase 2A (PP2A) activators, which reduce tau hyperphosphorylation.

A 2023 systematic review found that additional clinical studies are needed to show whether this approach is effective.

Healthy tau serves many important functions within cells all over the body.

However, the following lifestyle and diet strategies might help prevent toxic tau buildup:

  • Dietary strategies: Following the MIND diet, which combines aspects of the Mediterranean and DASH diets, may help improve cognitive function.
  • Exercise regularly: Consistent exercise has been shown to prevent Alzheimer’s and slow the disease’s progression.
  • Reduce your risk factors: Although Alzheimer’s disease has a significant genetic component, research has shown that certain behaviors — such as reducing stress, managing blood pressure, and staying mentally active — can reduce your risk.

Tau protein is an important component of all cells, including brain cells. Healthy tau acts as a stabilizer for microtubules, which form lattices that help cells keep their shape.

But research links tau phosphorylation and buildup in the brain to dementia, particularly Alzheimer’s disease. Doctors often measure tau levels when diagnosing Alzheimer’s.

Many current studies explore the role of tau in Alzheimer’s disease. In addition, several therapies to stop or slow tau phosphorylation and accumulation are in development.

To learn more about experimental therapies, talk with a healthcare professional or visit ClinicialTrials.gov.